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Sample records for residual method gmres

  1. Iterative methods for solving Ax=b, GMRES/FOM versus QMR/BiCG

    Energy Technology Data Exchange (ETDEWEB)

    Cullum, J. [IBM Research Division, Yorktown Heights, NY (United States)

    1996-12-31

    We study the convergence of GMRES/FOM and QMR/BiCG methods for solving nonsymmetric Ax=b. We prove that given the results of a BiCG computation on Ax=b, we can obtain a matrix B with the same eigenvalues as A and a vector c such that the residual norms generated by a FOM computation on Bx=c are identical to those generated by the BiCG computations. Using a unitary equivalence for each of these methods, we obtain test problems where we can easily vary certain spectral properties of the matrices. We use these test problems to study the effects of nonnormality on the convergence of GMRES and QMR, to study the effects of eigenvalue outliers on the convergence of QMR, and to compare the convergence of restarted GMRES, QMR, and BiCGSTAB across a family of normal and nonnormal problems. Our GMRES tests on nonnormal test matrices indicate that nonnormality can have unexpected effects upon the residual norm convergence, giving misleading indications of superior convergence over QMR when the error norms for GMRES are not significantly different from those for QMR. Our QMR tests indicate that the convergence of the QMR residual and error norms is influenced predominantly by small and large eigenvalue outliers and by the character, real, complex, or nearly real, of the outliers and the other eigenvalues. In our comparison tests QMR outperformed GMRES(10) and GMRES(20) on both the normal and nonnormal test matrices.

  2. New convergence results on the global GMRES method for diagonalizable matrices

    Science.gov (United States)

    Bellalij, M.; Jbilou, K.; Sadok, H.

    2008-10-01

    In the present paper, we give some new convergence results of the global GMRES method for multiple linear systems. In the case where the coefficient matrix A is diagonalizable, we derive new upper bounds for the Frobenius norm of the residual. We also consider the case of normal matrices and we propose new expressions for the norm of the residual.

  3. The Role Eigenvalues Play in Forming GMRES Residual Norms with Non-Normal Matrices

    Czech Academy of Sciences Publication Activity Database

    Meurant, G.; Duintjer Tebbens, Jurjen

    2015-01-01

    Roč. 68, č. 1 (2015), s. 143-165 ISSN 1017-1398 R&D Projects: GA ČR GA13-06684S Institutional support: RVO:67985807 Keywords : GMRES convergence * non-normal matrix * eigenvalues * residual norms Subject RIV: BA - General Mathematics Impact factor: 1.366, year: 2015

  4. The performances of R GPU implementations of the GMRES method

    Directory of Open Access Journals (Sweden)

    Bogdan Oancea

    2018-03-01

    Full Text Available Although the performance of commodity computers has improved drastically with the introduction of multicore processors and GPU computing, the standard R distribution is still based on single-threaded model of computation, using only a small fraction of the computational power available now for most desktops and laptops. Modern statistical software packages rely on high performance implementations of the linear algebra routines there are at the core of several important leading edge statistical methods. In this paper we present a GPU implementation of the GMRES iterative method for solving linear systems. We compare the performance of this implementation with a pure single threaded version of the CPU. We also investigate the performance of our implementation using different GPU packages available now for R such as gmatrix, gputools or gpuR which are based on CUDA or OpenCL frameworks.

  5. A block variant of the GMRES method on massively parallel processors

    Energy Technology Data Exchange (ETDEWEB)

    Li, Guangye [Cray Research, Inc., Eagan, MN (United States)

    1996-12-31

    This paper presents a block variant of the GMRES method for solving general unsymmetric linear systems. This algorithm generates a transformed Hessenberg matrix by solely using block matrix operations and block data communications. It is shown that this algorithm with block size s, denoted by BVGMRES(s,m), is theoretically equivalent to the GMRES(s*m) method. The numerical results show that this algorithm can be more efficient than the standard GMRES method on a cache based single CPU computer with optimized BLAS kernels. Furthermore, the gain in efficiency is more significant on MPPs due to both efficient block operations and efficient block data communications. Our numerical results also show that in comparison to the standard GMRES method, the more PEs that are used on an MPP, the more efficient the BVGMRES(s,m) algorithm is.

  6. Convergence of Inner-Iteration GMRES Methods for Rank-Deficient Least Squares Problems

    Czech Academy of Sciences Publication Activity Database

    Morikuni, Keiichi; Hayami, K.

    2015-01-01

    Roč. 36, č. 1 (2015), s. 225-250 ISSN 0895-4798 Institutional support: RVO:67985807 Keywords : least squares problem * iterative methods * preconditioner * inner-outer iteration * GMRES method * stationary iterative method * rank-deficient problem Subject RIV: BA - General Mathematics Impact factor: 1.883, year: 2015

  7. Some observations on weighted GMRES

    KAUST Repository

    Güttel, Stefan

    2014-01-10

    We investigate the convergence of the weighted GMRES method for solving linear systems. Two different weighting variants are compared with unweighted GMRES for three model problems, giving a phenomenological explanation of cases where weighting improves convergence, and a case where weighting has no effect on the convergence. We also present a new alternative implementation of the weighted Arnoldi algorithm which under known circumstances will be favourable in terms of computational complexity. These implementations of weighted GMRES are compared for a large number of examples. We find that weighted GMRES may outperform unweighted GMRES for some problems, but more often this method is not competitive with other Krylov subspace methods like GMRES with deflated restarting or BICGSTAB, in particular when a preconditioner is used. © 2014 Springer Science+Business Media New York.

  8. Tensor-GMRES method for large sparse systems of nonlinear equations

    Science.gov (United States)

    Feng, Dan; Pulliam, Thomas H.

    1994-01-01

    This paper introduces a tensor-Krylov method, the tensor-GMRES method, for large sparse systems of nonlinear equations. This method is a coupling of tensor model formation and solution techniques for nonlinear equations with Krylov subspace projection techniques for unsymmetric systems of linear equations. Traditional tensor methods for nonlinear equations are based on a quadratic model of the nonlinear function, a standard linear model augmented by a simple second order term. These methods are shown to be significantly more efficient than standard methods both on nonsingular problems and on problems where the Jacobian matrix at the solution is singular. A major disadvantage of the traditional tensor methods is that the solution of the tensor model requires the factorization of the Jacobian matrix, which may not be suitable for problems where the Jacobian matrix is large and has a 'bad' sparsity structure for an efficient factorization. We overcome this difficulty by forming and solving the tensor model using an extension of a Newton-GMRES scheme. Like traditional tensor methods, we show that the new tensor method has significant computational advantages over the analogous Newton counterpart. Consistent with Krylov subspace based methods, the new tensor method does not depend on the factorization of the Jacobian matrix. As a matter of fact, the Jacobian matrix is never needed explicitly.

  9. The Upper Bound for GMRES on Normal Tridiagonal Toeplitz Linear System

    Directory of Open Access Journals (Sweden)

    R. Doostaki∗

    2015-09-01

    Full Text Available The Generalized Minimal Residual method (GMRES is often used to solve a large and sparse system Ax = b. This paper establishes error bound for residuals of GMRES on solving an N × N normal tridiagonal Toeplitz linear system. This problem has been studied previously by Li [R.-C. Li, Convergence of CG and GMRES on a tridiagonal Toeplitz linear system, BIT 47 (3 (2007 577-599.], for two special right-hand sides b = e1, eN . Also, Li and Zhang [R.-C. Li, W. Zhang, The rate of convergence of GMRES on a tridiagonal Toeplitz linear system, Numer. Math. 112 (2009 267-293.] for non-symmetric matrix A, presented upper bound for GMRES residuals. But in this paper we establish the upper bound on normal tridiagonal Toeplitz linear systems for special right-hand sides b = b(lel, for 1  l  N

  10. Minimal residual method stronger than polynomial preconditioning

    Energy Technology Data Exchange (ETDEWEB)

    Faber, V.; Joubert, W.; Knill, E. [Los Alamos National Lab., NM (United States)] [and others

    1994-12-31

    Two popular methods for solving symmetric and nonsymmetric systems of equations are the minimal residual method, implemented by algorithms such as GMRES, and polynomial preconditioning methods. In this study results are given on the convergence rates of these methods for various classes of matrices. It is shown that for some matrices, such as normal matrices, the convergence rates for GMRES and for the optimal polynomial preconditioning are the same, and for other matrices such as the upper triangular Toeplitz matrices, it is at least assured that if one method converges then the other must converge. On the other hand, it is shown that matrices exist for which restarted GMRES always converges but any polynomial preconditioning of corresponding degree makes no progress toward the solution for some initial error. The implications of these results for these and other iterative methods are discussed.

  11. Properties of Worst-Case GMRES

    Czech Academy of Sciences Publication Activity Database

    Faber, V.; Liesen, J.; Tichý, Petr

    2013-01-01

    Roč. 34, č. 4 (2013), s. 1500-1519 ISSN 0895-4798 R&D Projects: GA ČR GA13-06684S Grant - others:GA AV ČR(CZ) M10041090 Institutional support: RVO:67985807 Keywords : GMRES method * worst-case convergence * ideal GMRES * matrix approximation problems * minmax Subject RIV: BA - General Mathematics Impact factor: 1.806, year: 2013

  12. GMRES and integral operators

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, C.T.; Xue, Z.Q. [North Carolina State Univ., Raleigh, NC (United States)

    1994-12-31

    Many discretizations of integral equations and compact fixed point problems are collectively compact and strongly convergent in spaces of continuous functions. These properties not only lead to stable and convergent approximations but also can be used in the construction of fast multilevel algorithms. Recently the GMRES algorithm has become a standard coarse mesh solver. The purpose of this paper is to show how the special properties of integral operators and their approximations are reflected in the performance of the GMRES iteration and how these properties can be used to strengthen the norm in which convergence takes place. The authors illustrate these ideas with composite Gauss rules for integral equations on the unit interval.

  13. On Investigating GMRES Convergence using Unitary Matrices

    Czech Academy of Sciences Publication Activity Database

    Duintjer Tebbens, Jurjen; Meurant, G.; Sadok, H.; Strakoš, Z.

    2014-01-01

    Roč. 450, 1 June (2014), s. 83-107 ISSN 0024-3795 Grant - others:GA AV ČR(CZ) M100301201; GA MŠk(CZ) LL1202 Institutional support: RVO:67985807 Keywords : GMRES convergence * unitary matrices * unitary spectra * normal matrices * Krylov residual subspace * Schur parameters Subject RIV: BA - General Mathematics Impact factor: 0.939, year: 2014

  14. Application of preconditioned GMRES to the numerical solution of the neutron transport equation

    International Nuclear Information System (INIS)

    Patton, B.W.; Holloway, J.P.

    2002-01-01

    The generalized minimal residual (GMRES) method with right preconditioning is examined as an alternative to both standard and accelerated transport sweeps for the iterative solution of the diamond differenced discrete ordinates neutron transport equation. Incomplete factorization (ILU) type preconditioners are used to determine their effectiveness in accelerating GMRES for this application. ILU(τ), which requires the specification of a dropping criteria τ, proves to be a good choice for the types of problems examined in this paper. The combination of ILU(τ) and GMRES is compared with both DSA and unaccelerated transport sweeps for several model problems. It is found that the computational workload of the ILU(τ)-GMRES combination scales nonlinearly with the number of energy groups and quadrature order, making this technique most effective for problems with a small number of groups and discrete ordinates. However, the cost of preconditioner construction can be amortized over several calculations with different source and/or boundary values. Preconditioners built upon standard transport sweep algorithms are also evaluated as to their effectiveness in accelerating the convergence of GMRES. These preconditioners show better scaling with such problem parameters as the scattering ratio, the number of discrete ordinates, and the number of spatial meshes. These sweeps based preconditioners can also be cast in a matrix free form that greatly reduces storage requirements

  15. Iterative Regularization with Minimum-Residual Methods

    DEFF Research Database (Denmark)

    Jensen, Toke Koldborg; Hansen, Per Christian

    2007-01-01

    subspaces. We provide a combination of theory and numerical examples, and our analysis confirms the experience that MINRES and MR-II can work as general regularization methods. We also demonstrate theoretically and experimentally that the same is not true, in general, for GMRES and RRGMRES their success......We study the regularization properties of iterative minimum-residual methods applied to discrete ill-posed problems. In these methods, the projection onto the underlying Krylov subspace acts as a regularizer, and the emphasis of this work is on the role played by the basis vectors of these Krylov...... as regularization methods is highly problem dependent....

  16. Iterative regularization with minimum-residual methods

    DEFF Research Database (Denmark)

    Jensen, Toke Koldborg; Hansen, Per Christian

    2006-01-01

    subspaces. We provide a combination of theory and numerical examples, and our analysis confirms the experience that MINRES and MR-II can work as general regularization methods. We also demonstrate theoretically and experimentally that the same is not true, in general, for GMRES and RRGMRES - their success......We study the regularization properties of iterative minimum-residual methods applied to discrete ill-posed problems. In these methods, the projection onto the underlying Krylov subspace acts as a regularizer, and the emphasis of this work is on the role played by the basis vectors of these Krylov...... as regularization methods is highly problem dependent....

  17. Validation of the interface-GMRES(R) solution method for fluid-structure interactions

    NARCIS (Netherlands)

    Michler, C.; Van Brummelen, E.H.; In 't Groen, R.; De Borst, R.

    2006-01-01

    The numerical solution of fluid-structure interactions with the customary subiteration method incurs numerous deficiencies. We validate a recently proposed solution method based on the conjugation of subiteration with a Newton-Krylov method, and demonstrate its superiority and beneficial

  18. Prescribing the behavior of early terminating GMRES and Arnoldi iterations

    Czech Academy of Sciences Publication Activity Database

    Duintjer Tebbens, Jurjen; Meurant, G.

    2014-01-01

    Roč. 65, č. 1 (2014), s. 69-90 ISSN 1017-1398 R&D Projects: GA AV ČR IAA100300802 Grant - others:GA AV ČR(CZ) M100301201 Institutional research plan: CEZ:AV0Z10300504 Keywords : Arnoldi process * early termination * GMRES method * prescribed GMRES convergence * Arnoldi method * prescribed Ritz values Subject RIV: BA - General Mathematics Impact factor: 1.417, year: 2014

  19. Right-Hand Side Dependent Bounds for GMRES Applied to Ill-Posed Problems

    KAUST Repository

    Pestana, Jennifer

    2014-01-01

    © IFIP International Federation for Information Processing 2014. In this paper we apply simple GMRES bounds to the nearly singular systems that arise in ill-posed problems. Our bounds depend on the eigenvalues of the coefficient matrix, the right-hand side vector and the nonnormality of the system. The bounds show that GMRES residuals initially decrease, as residual components associated with large eigenvalues are reduced, after which semi-convergence can be expected because of the effects of small eigenvalues.

  20. Smoothing-norm preconditioning for GMRES

    DEFF Research Database (Denmark)

    Hansen, Per Christian; Jensen, Toke Koldborg

    2004-01-01

    When GMRES is applied to a discrete ill-posed problem with a square matrix, then the iterates can be considered as regularized solutions. We show how to precondition GMRES in such a way that the iterations take into account a smoothing norm for the solution. This technique is well established...... for CGLS, but it does not apply directly to GMRES. We develop a similar technique that works for GMRES, without the need for modifications of the smoothing norm, and which preserves symmetry if the coefficient matrix is symmetric. We also discuss the efficient implementation of our algorithm, and we...

  1. Any Admissible Harmonic Ritz Value Set is Possible for GMRES

    Czech Academy of Sciences Publication Activity Database

    Du, K.; Duintjer Tebbens, Jurjen; Meurant, G.

    2017-01-01

    Roč. 47, September 18 (2017), s. 37-56 ISSN 1068-9613 R&D Projects: GA ČR GA13-06684S Institutional support: RVO:67985807 Keywords : Ritz values * harmonic Ritz values * GMRES convergence * prescribed residual norms * FOM convergence Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 0.925, year: 2016 http://etna.mcs.kent.edu/volumes/2011-2020/vol47/abstract.php?vol=47&pages=37-56

  2. A new adaptive GMRES algorithm for achieving high accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Sosonkina, M.; Watson, L.T.; Kapania, R.K. [Virginia Polytechnic Inst., Blacksburg, VA (United States); Walker, H.F. [Utah State Univ., Logan, UT (United States)

    1996-12-31

    GMRES(k) is widely used for solving nonsymmetric linear systems. However, it is inadequate either when it converges only for k close to the problem size or when numerical error in the modified Gram-Schmidt process used in the GMRES orthogonalization phase dramatically affects the algorithm performance. An adaptive version of GMRES (k) which tunes the restart value k based on criteria estimating the GMRES convergence rate for the given problem is proposed here. The essence of the adaptive GMRES strategy is to adapt the parameter k to the problem, similar in spirit to how a variable order ODE algorithm tunes the order k. With FORTRAN 90, which provides pointers and dynamic memory management, dealing with the variable storage requirements implied by varying k is not too difficult. The parameter k can be both increased and decreased-an increase-only strategy is described next followed by pseudocode.

  3. An efficient preconditioning technique using Krylov subspace methods for 3D characteristics solvers

    International Nuclear Information System (INIS)

    Dahmani, M.; Le Tellier, R.; Roy, R.; Hebert, A.

    2005-01-01

    The Generalized Minimal RESidual (GMRES) method, using a Krylov subspace projection, is adapted and implemented to accelerate a 3D iterative transport solver based on the characteristics method. Another acceleration technique called the self-collision rebalancing technique (SCR) can also be used to accelerate the solution or as a left preconditioner for GMRES. The GMRES method is usually used to solve a linear algebraic system (Ax=b). It uses K(r (o) ,A) as projection subspace and AK(r (o) ,A) for the orthogonalization of the residual. This paper compares the performance of these two combined methods on various problems. To implement the GMRES iterative method, the characteristics equations are derived in linear algebra formalism by using the equivalence between the method of characteristics and the method of collision probability to end up with a linear algebraic system involving fluxes and currents. Numerical results show good performance of the GMRES technique especially for the cases presenting large material heterogeneity with a scattering ratio close to 1. Similarly, the SCR preconditioning slightly increases the GMRES efficiency

  4. Any Ritz Value Behavior Is Possible for Arnoldi and for GMRES

    Czech Academy of Sciences Publication Activity Database

    Duintjer Tebbens, Jurjen; Meurant, G.

    2012-01-01

    Roč. 33, č. 3 (2012), s. 958-978 ISSN 0895-4798 R&D Projects: GA AV ČR IAA100300802 Grant - others:GA AV ČR(CZ) M100300901 Institutional research plan: CEZ:AV0Z10300504 Keywords : Ritz values * Arnoldi process * Arnoldi method * GMRES method * prescribed convergence * interlacing properties Subject RIV: BA - General Mathematics Impact factor: 1.342, year: 2012

  5. IRAM combined with multi-group GMRES for solving Matrix MOC

    International Nuclear Information System (INIS)

    Wu Wenbin; Li Qing; Wang Kan

    2014-01-01

    In the Matrix MOC, a linear algebraic equation system can be constructed by sweeping only once, and then solving the linear system takes the place of repeatedly characteristics sweeping. In neutron transport critical problems, k eff is traditionally computed by power iteration (PI), whose convergence rate is deeply dependent on the dominance ratio. Large problems of practical interest often have dominance ratios close to 1, leading to slow convergence of PI. In this study, k eff is computed by the Implicitly Restarted Arnoldi Method (IRAM) combined with multi-group GMRES, in which multi-group problems coupled by upscatter are solved directly, avoiding upscatter iteration. Numerical results of several benchmarks such as 2D C5G7 demonstrate that IRAM combined with multi-group GMRES can obtain good accuracy and higher efficiency compared with PI. (authors)

  6. Deflation of Eigenvalues for GMRES in Lattice QCD

    International Nuclear Information System (INIS)

    Morgan, Ronald B.; Wilcox, Walter

    2002-01-01

    Versions of GMRES with deflation of eigenvalues are applied to lattice QCD problems. Approximate eigenvectors corresponding to the smallest eigenvalues are generated at the same time that linear equations are solved. The eigenvectors improve convergence for the linear equations, and they help solve other right-hand sides

  7. The Cauchy method of residues

    CERN Document Server

    Mitrinović, Dragoslav S

    1993-01-01

    Volume 1, i. e. the monograph The Cauchy Method of Residues - Theory and Applications published by D. Reidel Publishing Company in 1984 is the only book that covers all known applications of the calculus of residues. They range from the theory of equations, theory of numbers, matrix analysis, evaluation of real definite integrals, summation of finite and infinite series, expansions of functions into infinite series and products, ordinary and partial differential equations, mathematical and theoretical physics, to the calculus of finite differences and difference equations. The appearance of Volume 1 was acknowledged by the mathematical community. Favourable reviews and many private communications encouraged the authors to continue their work, the result being the present book, Volume 2, a sequel to Volume 1. We mention that Volume 1 is a revised, extended and updated translation of the book Cauchyjev raeun ostataka sa primenama published in Serbian by Nau~na knjiga, Belgrade in 1978, whereas the greater part ...

  8. R3GMRES: including prior information in GMRES-type methods for discrete inverse problems

    DEFF Research Database (Denmark)

    Dong, Yiqiu; Garde, Henrik; Hansen, Per Christian

    2014-01-01

    Lothar Reichel and his collaborators proposed several iterative algorithms that augment the underlying Krylov subspace with an additional low-dimensional subspace in order to produce improved regularized solutions. We take a closer look at this approach and investigate a particular Regularized Ra...

  9. Multiple solutions to dense systems in radar scattering using a preconditioned block GMRES solver

    Energy Technology Data Exchange (ETDEWEB)

    Boyse, W.E. [Advanced Software Resources, Inc., Santa Clara, CA (United States)

    1996-12-31

    Multiple right-hand sides occur in radar scattering calculations in the computation of the simulated radar return from a body at a large number of angles. Each desired angle requires a right-hand side vector to be computed and the solution generated. These right-hand sides are naturally smooth functions of the angle parameters and this property is utilized in a novel way to compute solutions an order of magnitude faster than LINPACK The modeling technique addressed is the Method of Moments (MOM), i.e. a boundary element method for time harmonic Maxwell`s equations. Discretization by this method produces general complex dense systems of rank 100`s to 100,000`s. The usual way to produce the required multiple solutions is via LU factorization and solution routines such as found in LINPACK. Our method uses the block GMRES iterative method to directly iterate a subset of the desired solutions to convergence.

  10. Methods of measuring residual stresses in components

    International Nuclear Information System (INIS)

    Rossini, N.S.; Dassisti, M.; Benyounis, K.Y.; Olabi, A.G.

    2012-01-01

    Highlights: ► Defining the different methods of measuring residual stresses in manufactured components. ► Comprehensive study on the hole drilling, neutron diffraction and other techniques. ► Evaluating advantage and disadvantage of each method. ► Advising the reader with the appropriate method to use. -- Abstract: Residual stresses occur in many manufactured structures and components. Large number of investigations have been carried out to study this phenomenon and its effect on the mechanical characteristics of these components. Over the years, different methods have been developed to measure residual stress for different types of components in order to obtain reliable assessment. The various specific methods have evolved over several decades and their practical applications have greatly benefited from the development of complementary technologies, notably in material cutting, full-field deformation measurement techniques, numerical methods and computing power. These complementary technologies have stimulated advances not only in measurement accuracy and reliability, but also in range of application; much greater detail in residual stresses measurement is now available. This paper aims to classify the different residual stresses measurement methods and to provide an overview of some of the recent advances in this area to help researchers on selecting their techniques among destructive, semi destructive and non-destructive techniques depends on their application and the availabilities of those techniques. For each method scope, physical limitation, advantages and disadvantages are summarized. In the end this paper indicates some promising directions for future developments.

  11. Method for residual household waste composition studies.

    Science.gov (United States)

    Sahimaa, Olli; Hupponen, Mari; Horttanainen, Mika; Sorvari, Jaana

    2015-12-01

    The rising awareness of decreasing natural resources has brought forward the idea of a circular economy and resource efficiency in Europe. As a part of this movement, European countries have identified the need to monitor residual waste flows in order to make recycling more efficient. In Finland, studies on the composition of residual household waste have mostly been conducted using different methods, which makes the comparison of the results difficult. The aim of this study was to develop a reliable method for residual household waste composition studies. First, a literature review on European study methods was performed. Also, 19 Finnish waste composition studies were compared in order to identify the shortcomings of the current Finnish residual household waste composition data. Moreover, the information needs of different waste management authorities concerning residual household waste were studied through a survey and personal interviews. Stratification, sampling, the classification of fractions and statistical analysis were identified as the key factors in a residual household waste composition study. The area studied should be divided into non-overlapping strata in order to decrease the heterogeneity of waste and enable comparisons between different waste producers. A minimum of six subsamples, each 100 kg, from each stratum should be sorted. Confidence intervals for each waste category should be determined in order to evaluate the applicability of the results. A new three-level classification system was created based on Finnish stakeholders' information needs and compared to four other European waste composition study classifications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Geostatistical methods applied to field model residuals

    DEFF Research Database (Denmark)

    Maule, Fox; Mosegaard, K.; Olsen, Nils

    consists of measurement errors and unmodelled signal), and is typically assumed to be uncorrelated and Gaussian distributed. We have applied geostatistical methods to analyse the residuals of the Oersted(09d/04) field model [http://www.dsri.dk/Oersted/Field_models/IGRF_2005_candidates/], which is based......The geomagnetic field varies on a variety of time- and length scales, which are only rudimentary considered in most present field models. The part of the observed field that can not be explained by a given model, the model residuals, is often considered as an estimate of the data uncertainty (which...... on 5 years of Ørsted and CHAMP data, and includes secular variation and acceleration, as well as low-degree external (magnetospheric) and induced fields. The analysis is done in order to find the statistical behaviour of the space-time structure of the residuals, as a proxy for the data covariances...

  13. A new implementation of the CMRH method for solving dense linear systems

    Science.gov (United States)

    Heyouni, M.; Sadok, H.

    2008-04-01

    The CMRH method [H. Sadok, Methodes de projections pour les systemes lineaires et non lineaires, Habilitation thesis, University of Lille1, Lille, France, 1994; H. Sadok, CMRH: A new method for solving nonsymmetric linear systems based on the Hessenberg reduction algorithm, Numer. Algorithms 20 (1999) 303-321] is an algorithm for solving nonsymmetric linear systems in which the Arnoldi component of GMRES is replaced by the Hessenberg process, which generates Krylov basis vectors which are orthogonal to standard unit basis vectors rather than mutually orthogonal. The iterate is formed from these vectors by solving a small least squares problem involving a Hessenberg matrix. Like GMRES, this method requires one matrix-vector product per iteration. However, it can be implemented to require half as much arithmetic work and less storage. Moreover, numerical experiments show that this method performs accurately and reduces the residual about as fast as GMRES. With this new implementation, we show that the CMRH method is the only method with long-term recurrence which requires not storing at the same time the entire Krylov vectors basis and the original matrix as in the GMRES algorithmE A comparison with Gaussian elimination is provided.

  14. Residual replacement strategies for Krylov subspace iterative methods for the convergence of true residuals

    NARCIS (Netherlands)

    Vorst, H.A. van der; Ye, Q.

    1999-01-01

    In this paper, a strategy is proposed for alternative computations of the residual vectors in Krylov subspace methods, which improves the agreement of the computed residuals and the true residuals to the level of O(u)kAkkxk. Building on earlier ideas on residual replacement and on insights in

  15. Method of producing pitch (distillation residue)

    Energy Technology Data Exchange (ETDEWEB)

    Stepanenko, M.A.; Belkina, T.V.; Krysin, V.P.

    1979-08-15

    A method is proposed for producing pitch by mixing hard coal pitch with anthracene fraction and thermal treatment of the mixture. The method is distinguished in that in order to increase the quality of the pitch, the anthracene fraction is subjected to thermal treatment at 250-300/sup 0/ for 10-13 hours in the presence of air. This duration of heat treatment allows one to build up in the anthracene fraction up to 20-24% of material which is not soluble and toluene, without the formation of products which are not soluble in quinoline. The fraction prepared in this manner is inserted into the initial pitch in the ratio 1:2 up to 1:9, the mixture is subject to heat treatment at temperature 360-380/sup 0/ and air consumption 7-91/kgX hours until the production of pitch with softening temperature of 85-90/sup 0/. As the initial raw material we used pitch with softening temperature of 60/sup 0/, content of substances which are not soluble in quinoline, 2.0% which are not soluble and toluene 20.6% and coking residue of 49.2%. Example. 80 grams of anthracene fraction is added to 320 grams of pitch. The anthracene fraction is subjected previously to heat treatment at 300/sup 0/ for 13 hours in the presence of air, supplied in the amount of 9 liters per hour. As a result of the heat treatment of the content of materials which are not soluble in toluence in the anthracene fraction is 24.0%, in quinoline it is 0.1%. The ratio of a pitch and thermally treated anthracene fraction in the mixture was 4:l. The produced mixture was subjected to heat treatment at 360/sup 0/ for 1.5 hours with air supply in the amount of 7 liters/ kilograms/hours. Pitch is produced with the following characteristics: softening temperature 88/sup 0/, content of substances which are not soluble in toluene 32.5%, in quinilone, 6.0%, coking residue, 56.7%. The invention can be used in the chemical coking and petrochemical industry.

  16. The method for measuring residual stress in stainless steel pipes

    International Nuclear Information System (INIS)

    Shimov, Georgy; Rozenbaum, Mikhail; Serebryakov, Alexandr; Serebryakov, Andrey

    2016-01-01

    The main reason of appearance and growth of corrosion damages of the nuclear steam generator heat exchanger tubes is the process of stress-corrosion cracking of metal under the influence of residual tensile stress. Methods used in the production for estimating residual stresses (such as a method of ring samples) allow measuring only the average tangential stress of the pipe wall. The method of ring samples does not allow to assess the level of residual stress in the surface layer of the pipe. This paper describes an experimental method for measuring the residual stresses on the pipe surface by etching a thin surface layer of the metal. The construction and working principle of a trial installation are described. The residual stresses in the wall of the tubes 16 × 1.5 mm (steel AISI 321) for nuclear steam generators is calculated. Keywords: heat exchange pipes, stress corrosion cracking, residual stresses, stress distribution, stress measurement.

  17. Satellite Magnetic Residuals Investigated With Geostatistical Methods

    DEFF Research Database (Denmark)

    Fox Maule, Chaterine; Mosegaard, Klaus; Olsen, Nils

    2005-01-01

    The geomagnetic field varies on a variety of time- and length scales, which are only rudimentarily considered in most present field models. The part of the observed field that cannot be explained by a given model, the model residuals, is often considered as an estimate of the data uncertainty (wh...

  18. Deflation of eigenvalues for iterative methods in lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Darnell, Dean; Morgan, Ronald B.; Wilcox, Walter

    2004-03-01

    Work on generalizing the deflated, restarted GMRES algorithm, useful in lattice studies using stochastic noise methods, is reported. We first show how the multi-mass extension of deflated GMRES can be implemented. We then give a deflated GMRES method that can be used on multiple right-hand sides of A{chi} = b in an efficient manner. We also discuss and give numerical results on the possibilty of combining deflated GMRES for the first right hand side with a deflated BiCGStab algorithm for the subsequent right hand sides.

  19. Deflation of eigenvalues for iterative methods in lattice QCD

    International Nuclear Information System (INIS)

    Darnell, Dean; Morgan, Ronald B.; Wilcox, Walter

    2004-01-01

    Work on generalizing the deflated, restarted GMRES algorithm, useful in lattice studies using stochastic noise methods, is reported. We first show how the multi-mass extension of deflated GMRES can be implemented. We then give a deflated GMRES method that can be used on multiple right-hand sides of Aχ = b in an efficient manner. We also discuss and give numerical results on the possibilty of combining deflated GMRES for the first right hand side with a deflated BiCGStab algorithm for the subsequent right hand sides

  20. The new method for the residual gas density measurements

    CERN Document Server

    Anashin, V V; Krasnov, A A; Malyshev, O B; Nas'mov, V P; Pyata, E I; Shaftan, T V

    2001-01-01

    A new method of measurement for residual gas density in the vacuum chambers in presence of synchrotron radiation (SR) is described. The method is based on using a photomultiplier tube for the detection of the SR-stimulated residual gas luminescence, which is proportional to the residual gas density and SR intensity. The design of the experimental setup and results of the measurements of densities of residual gases (H sub 2 , CO sub 2 , CO, N sub 2 , Ar and O sub 2) are submitted.

  1. Preconditioned iterative methods for space-time fractional advection-diffusion equations

    Science.gov (United States)

    Zhao, Zhi; Jin, Xiao-Qing; Lin, Matthew M.

    2016-08-01

    In this paper, we propose practical numerical methods for solving a class of initial-boundary value problems of space-time fractional advection-diffusion equations. First, we propose an implicit method based on two-sided Grünwald formulae and discuss its stability and consistency. Then, we develop the preconditioned generalized minimal residual (preconditioned GMRES) method and preconditioned conjugate gradient normal residual (preconditioned CGNR) method with easily constructed preconditioners. Importantly, because resulting systems are Toeplitz-like, fast Fourier transform can be applied to significantly reduce the computational cost. We perform numerical experiments to demonstrate the efficiency of our preconditioners, even in cases with variable coefficients.

  2. Treatment Method for Fermi Barrel Sodium Metal Residues

    Energy Technology Data Exchange (ETDEWEB)

    Steven R. Sherman; Collin J. Knight

    2005-06-01

    Fermi barrels are 55-gallon drums that once contained bulk sodium metal from the shutdown Fermi 1 breeder reactor facility, and now contain residual sodium metal and other sodium/air reaction products. This report provides a residual sodium treatment method and proposed quality assurance steps that will ensure that all residual sodium is deactivated and removed from the Fermi barrels before disposal. The treatment method is the application of humidified carbon dioxide to the residual sodium followed by a water wash. The experimental application of the treatment method to six Fermi barrels is discussed, and recommendations are provided for further testing and evaluation of the method. Though more testing would allow for a greater refinement of the treatment technique, enough data has been gathered from the tests already performed to prove that 100% compliance with stated waste criteria can be achieved.

  3. A Nonlinear GMRES Optimization Algorithm for Canonical Tensor Decomposition

    OpenAIRE

    De Sterck, Hans

    2011-01-01

    A new algorithm is presented for computing a canonical rank-R tensor approximation that has minimal distance to a given tensor in the Frobenius norm, where the canonical rank-R tensor consists of the sum of R rank-one components. Each iteration of the method consists of three steps. In the first step, a tentative new iterate is generated by a stand-alone one-step process, for which we use alternating least squares (ALS). In the second step, an accelerated iterate is generated by a nonlinear g...

  4. Convergence of a residual based artificial viscosity finite element method

    KAUST Repository

    Nazarov, Murtazo

    2013-02-01

    We present a residual based artificial viscosity finite element method to solve conservation laws. The Galerkin approximation is stabilized by only residual based artificial viscosity, without any least-squares, SUPG, or streamline diffusion terms. We prove convergence of the method, applied to a scalar conservation law in two space dimensions, toward an unique entropy solution for implicit time stepping schemes. © 2012 Elsevier B.V. All rights reserved.

  5. Testing the efficiency of extraction of incurred residues from soil with optimized multi-residue method.

    Science.gov (United States)

    Suszter, Gabriella K; Ambrus, Árpád

    2017-08-03

    The reproducibility of extraction of residues from spiked soil samples and from soils containing incurred residues was tested with 14 C-labeled test compounds of different physical-chemical properties. Nearly 100% of the compounds added to the sample before extraction could be recovered with an average reproducibility relative standard deviation (CV) of 5.4%. The additional steps of the determination process (cleanup, evaporation, etc.) contributed to the major part of the variability of the results (CV = 10-20%). The incurred residues were most efficiently extracted with acetone for 30 min followed by the mixture of acetone/ethyl acetate 1:1 for additional 30 min. However, they could only be recovered at various extent (64-90% of total residues), underlying the importance of testing the efficiency of extraction. The residues were identified and quantified by gas chromatography applying thermionic detector. The performance parameters of the method complied with the international method validation guidelines, and they proved to be robust and suitable for determination of pesticide residues in soils of widely different physical-chemical properties.

  6. Residual Stress Analysis Based on Acoustic and Optical Methods

    Directory of Open Access Journals (Sweden)

    Sanichiro Yoshida

    2016-02-01

    Full Text Available Co-application of acoustoelasticity and optical interferometry to residual stress analysis is discussed. The underlying idea is to combine the advantages of both methods. Acoustoelasticity is capable of evaluating a residual stress absolutely but it is a single point measurement. Optical interferometry is able to measure deformation yielding two-dimensional, full-field data, but it is not suitable for absolute evaluation of residual stresses. By theoretically relating the deformation data to residual stresses, and calibrating it with absolute residual stress evaluated at a reference point, it is possible to measure residual stresses quantitatively, nondestructively and two-dimensionally. The feasibility of the idea has been tested with a butt-jointed dissimilar plate specimen. A steel plate 18.5 mm wide, 50 mm long and 3.37 mm thick is braze-jointed to a cemented carbide plate of the same dimension along the 18.5 mm-side. Acoustoelasticity evaluates the elastic modulus at reference points via acoustic velocity measurement. A tensile load is applied to the specimen at a constant pulling rate in a stress range substantially lower than the yield stress. Optical interferometry measures the resulting acceleration field. Based on the theory of harmonic oscillation, the acceleration field is correlated to compressive and tensile residual stresses qualitatively. The acoustic and optical results show reasonable agreement in the compressive and tensile residual stresses, indicating the feasibility of the idea.

  7. A Novel Residual Frequency Estimation Method for GNSS Receivers.

    Science.gov (United States)

    Nguyen, Tu Thi-Thanh; La, Vinh The; Ta, Tung Hai

    2018-01-04

    In Global Navigation Satellite System (GNSS) receivers, residual frequency estimation methods are traditionally applied in the synchronization block to reduce the transient time from acquisition to tracking, or they are used within the frequency estimator to improve its accuracy in open-loop architectures. There are several disadvantages in the current estimation methods, including sensitivity to noise and wide search space size. This paper proposes a new residual frequency estimation method depending on differential processing. Although the complexity of the proposed method is higher than the one of traditional methods, it can lead to more accurate estimates, without increasing the size of the search space.

  8. Application of the contour method to validate residual stress predictions

    International Nuclear Information System (INIS)

    Welding is the most widespread method employed to join metallic components in nuclear power plants. This is an aggressive process that introduces complex three-dimensional residual stresses of substantial magnitude into engineering components. For safety-critical applications it can be of crucial importance to have an accurate characterisation of the residual stress field present in order to assess plant lifetime and risk of failure. Finite element modelling approaches are being increasingly employed by engineers to predict welding residual stresses. However, such predictions are challenging owing to the innate complexity of the welding process and can give highly variable results. Therefore, it is always desirable to validate residual stress predictions by experimental data. This paper illustrates how the contour method of measuring residual stress can be applied to various weldments in order to provide high quality experimental data. The contour method results are compared with data obtained by other well-established residual stress measurement techniques such as neutron diffraction and slitting methods and show a very satisfactory correlation. (author)

  9. Detection of residues antibiotics in food using a microbiological method

    International Nuclear Information System (INIS)

    Ben Ali, Ahmed

    2007-01-01

    Antibiotics are effective therapeutic agents because of their property of selective bacterial toxicity which helps controlling infections. Animals, just like humans, can be treated with antibiotics. This use of antibiotics can lead to the development of resistance. Resistant strains may cause severe infections in humans and animals. In addition, antibiotic residues might represent a problem for human health. Our objective is to develop a microbiological method for the detection of antibiotic residues in poultry(muscle, liver,...). For this purpose, antibiotic sensitive bacteria and selective agar media were used. An inhibition growth zone surrounds each of the food samples containing antibiotic residues after a prescribed incubation time. (Author). 23 refs

  10. Parallel Jacobian-free Newton Krylov solution of the discrete ordinates method with flux limiters for 3D radiative transfer

    International Nuclear Information System (INIS)

    Godoy, William F.; Liu Xu

    2012-01-01

    The present study introduces a parallel Jacobian-free Newton Krylov (JFNK) general minimal residual (GMRES) solution for the discretized radiative transfer equation (RTE) in 3D, absorbing, emitting and scattering media. For the angular and spatial discretization of the RTE, the discrete ordinates method (DOM) and the finite volume method (FVM) including flux limiters are employed, respectively. Instead of forming and storing a large Jacobian matrix, JFNK methods allow for large memory savings as the required Jacobian-vector products are rather approximated by semiexact and numerical formulations, for which convergence and computational times are presented. Parallelization of the GMRES solution is introduced in a combined memory-shared/memory-distributed formulation that takes advantage of the fact that only large vector arrays remain in the JFNK process. Results are presented for 3D test cases including a simple homogeneous, isotropic medium and a more complex non-homogeneous, non-isothermal, absorbing–emitting and anisotropic scattering medium with collimated intensities. Additionally, convergence and stability of Gram–Schmidt and Householder orthogonalizations for the Arnoldi process in the parallel GMRES algorithms are discussed and analyzed. Overall, the introduction of JFNK methods results in a parallel, yet scalable to the tested 2048 processors, and memory affordable solution to 3D radiative transfer problems without compromising the accuracy and convergence of a Newton-like solution.

  11. FPGA Implementation of Uniform Random Number based on Residue Method

    Directory of Open Access Journals (Sweden)

    Zulfikar .

    2014-04-01

    Full Text Available This paper presents the implementation and comparisons of uniform random number on Field Programable Gate Array (FPGA. Uniform random numbers are generated based on residue method. The circuit of generating uniform random number is presented in general view. The circuit is constructed from a multiplexer, a multiplier, buffers and some basic gates. FPGA implementation of the designed circuit has been done into various Xilinx chips. Simulation results are viewed clearly in the paper. Random numbers are generated based on different parameters. Comparisons upon occupied area and maximum frequency from different Xilinx chip are examined. Virtex 7 is the fastest chip and Virtex 4 is the best choice in terms of occupied area. Finally, Uniform random numbers have been generated successfully on FPGA using residue method.Keywords: FPGA implementation, random number, uniform random number, residue method, Xilinx chips

  12. Residual-based model diagnosis methods for mixture cure models.

    Science.gov (United States)

    Peng, Yingwei; Taylor, Jeremy M G

    2017-06-01

    Model diagnosis, an important issue in statistical modeling, has not yet been addressed adequately for cure models. We focus on mixture cure models in this work and propose some residual-based methods to examine the fit of the mixture cure model, particularly the fit of the latency part of the mixture cure model. The new methods extend the classical residual-based methods to the mixture cure model. Numerical work shows that the proposed methods are capable of detecting lack-of-fit of a mixture cure model, particularly in the latency part, such as outliers, improper covariate functional form, or nonproportionality in hazards if the proportional hazards assumption is employed in the latency part. The methods are illustrated with two real data sets that were previously analyzed with mixture cure models. © 2016, The International Biometric Society.

  13. Rapid multi-residue method for the determination of pesticide ...

    African Journals Online (AJOL)

    Exposure to pesticides can represent a potential risk to humans. Agricultural workers are at risk of chronic toxicity. Hence, the evaluation of pesticide residues in their blood gives an indication about the extent of exposure and help in assessing adverse health effects. The aim of our study was to develop analytical method for ...

  14. Smoothing-Norm Preconditioning for Regularizing Minimum-Residual Methods

    DEFF Research Database (Denmark)

    Hansen, Per Christian; Jensen, Toke Koldborg

    2006-01-01

    take into account a smoothing norm for the solution. This technique is well established for CGLS, but it does not immediately carry over to minimum-residual methods when the smoothing norm is a seminorm or a Sobolev norm. We develop a new technique which works for any smoothing norm of the form $\\|L...

  15. Ceramic residue for producing cements, method for the production thereof, and cements containing same

    OpenAIRE

    Sánchez de Rojas, María Isabel; Frías, Moisés; Asensio, Eloy; Medina Martínez, César

    2014-01-01

    [EN] The invention relates to a ceramic residue produced from construction and demolition residues, as a puzzolanic component of cements. The invention also relates to a method for producing said ceramic residues and to another method of producing cements using said residues. This type of residue is collected in recycling plants, where it is managed. This invention facilitates a potential commercial launch.

  16. Prediction of residual stress using explicit finite element method

    Directory of Open Access Journals (Sweden)

    W.A. Siswanto

    2015-12-01

    Full Text Available This paper presents the residual stress behaviour under various values of friction coefficients and scratching displacement amplitudes. The investigation is based on numerical solution using explicit finite element method in quasi-static condition. Two different aeroengine materials, i.e. Super CMV (Cr-Mo-V and Titanium alloys (Ti-6Al-4V, are examined. The usage of FEM analysis in plate under normal contact is validated with Hertzian theoretical solution in terms of contact pressure distributions. The residual stress distributions along with normal and shear stresses on elastic and plastic regimes of the materials are studied for a simple cylinder-on-flat contact configuration model subjected to normal loading, scratching and followed by unloading. The investigated friction coefficients are 0.3, 0.6 and 0.9, while scratching displacement amplitudes are 0.05 mm, 0.10 mm and 0.20 mm respectively. It is found that friction coefficient of 0.6 results in higher residual stress for both materials. Meanwhile, the predicted residual stress is proportional to the scratching displacement amplitude, higher displacement amplitude, resulting in higher residual stress. It is found that less residual stress is predicted on Super CMV material compared to Ti-6Al-4V material because of its high yield stress and ultimate strength. Super CMV material with friction coefficient of 0.3 and scratching displacement amplitude of 0.10 mm is recommended to be used in contact engineering applications due to its minimum possibility of fatigue.

  17. Proficiency test on the determination of pesticide residues in grapes with multi-residue methods.

    Science.gov (United States)

    Dehouck, Pieter; Grimalt, Susana; Dabrio, Marta; Cordeiro, Fernando; Fiamegos, Yiannis; Robouch, Piotr; Fernández-Alba, Amadeo R; de la Calle, Beatriz

    2015-05-22

    This manuscript presents the results of the International Measurement Evaluation Programme 37 (IMEP-37) study, a proficiency test (PT) which was organised to assess the world-wide performance of food control laboratories on the determination of pesticide residues in grapes. This PT supports the implementation of Regulation (EC) No 396/2005 on maximum residue levels of pesticides in or on food and feed of plant and animal origin. Eighty-one participants reported results, forty from EU Member States and forty-one from outside the EU. The test item was a grape sample spiked with 20 selected pesticides. The results of the participants were rated with z- and zeta (ζ-) scores in accordance with ISO 13528 and ISO 17043. The standard deviation for the proficiency assessment, σˆ, of this PT was set at 25% for the 20 measured pesticides based on previous experience with similar measurands. The results reported to IMEP-37 showed that the participants performed satisfactorily, ranging from 81% (carbendazim) to 97% (azoxystrobin, penconazole, pyrimethanil) of the participating laboratories. However, only 30% of the participants managed to analyze all pesticides satisfactorily. Overall, the performance of the participants in this PT was good but there is room for improvement in the development of multi-residue methods for the simultaneous analysis of a large number of pesticides with an increased accuracy. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  18. Analytical Methods for Detonation Residues of Insensitive Munitions

    Science.gov (United States)

    Walsh, Marianne E.

    2016-01-01

    Analytical methods are described for the analysis of post-detonation residues from insensitive munitions. Standard methods were verified or modified to obtain the mass of residues deposited per round. In addition, a rapid chromatographic separation was developed and used to measure the mass of NTO (3-nitro-1,2,4-triazol-5-one), NQ (nitroguanidine) and DNAN (2,4-dinitroanisole). The HILIC (hydrophilic-interaction chromatography) separation described here uses a trifunctionally-bonded amide phase to retain the polar analytes. The eluent is 75/25 v/v acetonitrile/water acidified with acetic acid, which is also suitable for LC/MS applications. Analytical runtime was three minutes. Solid phase extraction and LC/MS conditions are also described.

  19. Validation of a residue method to determine pesticide residues in cucumber by using nuclear techniques

    International Nuclear Information System (INIS)

    Baysoyu, D.; Tiryaki, O.; Secer, E.; Aydin, G.

    2009-01-01

    In this study, a multi-residue method using ethyl acetate for extraction and gel permeation chromatography for clean-up was validated to determine chlorpyrifos, malathion and dichlorvos in cucumber by gas chromatography. For this purpose, homogenized cucumber samples were fortified with pesticides at 0.02 0.2, 0.8 and 1 mg/kg levels. The efficiency and repeatability of the method in extraction and cleanup steps were performed using 1 4C-carbaryl by radioisotope tracer technique. 1 4C-carbaryl recoveries after the extraction and cleanup steps were between 92.63-111.73 % with a repeatability of 4.85% (CV) and 74.83-102.22 % with a repeatability of 7.19% (CV), respectively. The homogeneity of analytical samples and the stability of pesticides during homogenization were determined using radio tracer technique and chromatographic methods, respectively.

  20. Rapid surface enhanced Raman scattering detection method for chloramphenicol residues

    Science.gov (United States)

    Ji, Wei; Yao, Weirong

    2015-06-01

    Chloramphenicol (CAP) is a widely used amide alcohol antibiotics, which has been banned from using in food producing animals in many countries. In this study, surface enhanced Raman scattering (SERS) coupled with gold colloidal nanoparticles was used for the rapid analysis of CAP. Density functional theory (DFT) calculations were conducted with Gaussian 03 at the B3LYP level using the 3-21G(d) and 6-31G(d) basis sets to analyze the assignment of vibrations. Affirmatively, the theoretical Raman spectrum of CAP was in complete agreement with the experimental spectrum. They both exhibited three strong peaks characteristic of CAP at 1104 cm-1, 1344 cm-1, 1596 cm-1, which were used for rapid qualitative analysis of CAP residues in food samples. The use of SERS as a method for the measurements of CAP was explored by comparing use of different solvents, gold colloidal nanoparticles concentration and absorption time. The method of the detection limit was determined as 0.1 μg/mL using optimum conditions. The Raman peak at 1344 cm-1 was used as the index for quantitative analysis of CAP in food samples, with a linear correlation of R2 = 0.9802. Quantitative analysis of CAP residues in foods revealed that the SERS technique with gold colloidal nanoparticles was sensitive and of a good stability and linear correlation, and suited for rapid analysis of CAP residue in a variety of food samples.

  1. Rapid Methods for detection of Veterinary Drug residues in Meat

    Directory of Open Access Journals (Sweden)

    Chandan

    2010-10-01

    Full Text Available The use of substances having hormonal or thyreostatic action as well as b-agonists is banned in many countries. However, sometimes forbidden drugs may be added to feeds for illegal administration to farm animals for promoting increased muscle development or increased water retention and thus obtain an economical benefit. The result is a fraudulent overweight of meat but, what is worse, residues of these substances may remain in meat and may pose a real threat to the consumer either through exposure to the residues, transfer of antibiotic resistance or allergy risk. This has exerted a great concern among the meat consumers. The control of the absence of these forbidden substances in animal foods and feeds is regulated in the European Union by Directive 96/23/EC on measures to monitor certain substances and residues in live animals and animal products. Analytical methodology, including criteria for identification and confirmation, for the monitoring of compliance was also given in Decisions 93/256/EEC and 93/257/EEC. More recently, Decision 2002/657/EC provided rules for the analytical methods to be used in testing of official samples. New substances with anabolic properties are being detected year by year increasing the list of forbidden compounds to be tested. Furthermore, the extended practice consisting in the use of “cocktails” (mixtures of low amounts of several substances that exert a synergistic effect to have a similar growth promotion, reduces the margin for an effective analytical detection. Thus, the evolution of the “black market” is making really difficult to have an effective analytical control of the residues of these substances in foods of animal origin. Control laboratories must face an increasing demand of analysis like the growing number of residues to be analysed in different types of samples, the strict guidelines for analytical methodologies according to the latest Directives, the increased costs of such new

  2. A review of experimental methods for determining residual creep life

    International Nuclear Information System (INIS)

    Bolton, C.J.

    1977-11-01

    Experimental methods available for determining how much creep life remains at a particular time in the high temperature service of a component are reviewed. After a brief consideration of the limitations of stress rupture extrapolation techniques, the application of post-exposure creep testing is considered. Ways of assessing the effect of microstructural degradation on residual life are then reviewed. It is pointed out that while this type of work will be useful for certain materials, there are other materials in which 'mechanical damage' such as cavitation will be more important. Cavitation measurement techniques are therefore reviewed. The report ends with a brief consideration of the use of crack growth measurements in assessing the residual life of cracked components. (author)

  3. Minimal Residual Disease Assessment in Lymphoma: Methods and Applications.

    Science.gov (United States)

    Herrera, Alex F; Armand, Philippe

    2017-12-01

    Standard methods for disease response assessment in patients with lymphoma, including positron emission tomography and computed tomography scans, are imperfect. In other hematologic malignancies, particularly leukemias, the ability to detect minimal residual disease (MRD) is increasingly influencing treatment paradigms. However, in many subtypes of lymphoma, the application of MRD assessment techniques, like flow cytometry or polymerase chain reaction-based methods, has been challenging because of the absence of readily detected circulating disease or canonic chromosomal translocations. Newer MRD detection methods that use next-generation sequencing have yielded promising results in a number of lymphoma subtypes, fueling the hope that MRD detection may soon be applicable in clinical practice for most patients with lymphoma. MRD assessment can provide real-time information about tumor burden and response to therapy, noninvasive genomic profiling, and monitoring of clonal dynamics, allowing for many possible applications that could significantly affect the care of patients with lymphoma. Further validation of MRD assessment methods, including the incorporation of MRD assessment into clinical trials in patients with lymphoma, will be critical to determine how best to deploy MRD testing in routine practice and whether MRD assessment can ultimately bring us closer to the goal of personalized lymphoma care. In this review article, we describe the methods available for detecting MRD in patients with lymphoma and their relative advantages and disadvantages. We discuss preliminary results supporting the potential applications for MRD testing in the care of patients with lymphoma and strategies for including MRD assessment in lymphoma clinical trials.

  4. Economic methods for the utilisation of logging residues

    Directory of Open Access Journals (Sweden)

    Gałęzia Tomasz

    2016-03-01

    Full Text Available There are several ways of using logging residues, and the two most common ones in the State Forests are wood chip production for energy purposes by mobile machinery and crushing by tractor-powered crushers. In this research, an economy-based approach was used to compare these methods and assess whether chip production is superior to crushing for clearing a felling area. The average revenues from the sale of wood biomass in the form of wood chips and the average costs of crushing in the Pomorze Forest District were analysed for the period from January 2012 until June 2014. Both revenues and costs (such as fuel, operator’s wage, piling costs, depreciation, insurance and garaging costs were extracted from the State Forests’ database using data-mining software.

  5. Residual-driven online generalized multiscale finite element methods

    KAUST Repository

    Chung, Eric T.

    2015-09-08

    The construction of local reduced-order models via multiscale basis functions has been an area of active research. In this paper, we propose online multiscale basis functions which are constructed using the offline space and the current residual. Online multiscale basis functions are constructed adaptively in some selected regions based on our error indicators. We derive an error estimator which shows that one needs to have an offline space with certain properties to guarantee that additional online multiscale basis function will decrease the error. This error decrease is independent of physical parameters, such as the contrast and multiple scales in the problem. The offline spaces are constructed using Generalized Multiscale Finite Element Methods (GMsFEM). We show that if one chooses a sufficient number of offline basis functions, one can guarantee that additional online multiscale basis functions will reduce the error independent of contrast. We note that the construction of online basis functions is motivated by the fact that the offline space construction does not take into account distant effects. Using the residual information, we can incorporate the distant information provided the offline approximation satisfies certain properties. In the paper, theoretical and numerical results are presented. Our numerical results show that if the offline space is sufficiently large (in terms of the dimension) such that the coarse space contains all multiscale spectral basis functions that correspond to small eigenvalues, then the error reduction by adding online multiscale basis function is independent of the contrast. We discuss various ways computing online multiscale basis functions which include a use of small dimensional offline spaces.

  6. Standard test method for determining residual stresses by the hole-drilling strain-gage method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 Residual Stress Determination: 1.1.1 This test method specifies a hole-drilling procedure for determining residual stress profiles near the surface of an isotropic linearly elastic material. The test method is applicable to residual stress profile determinations where in-plane stress gradients are small. The stresses may remain approximately constant with depth (“uniform” stresses) or they may vary significantly with depth (“non-uniform” stresses). The measured workpiece may be “thin” with thickness much less than the diameter of the drilled hole or “thick” with thickness much greater than the diameter of the drilled hole. Only uniform stress measurements are specified for thin workpieces, while both uniform and non-uniform stress measurements are specified for thick workpieces. 1.2 Stress Measurement Range: 1.2.1 The hole-drilling method can identify in-plane residual stresses near the measured surface of the workpiece material. The method gives localized measurements that indicate the...

  7. Residual stress measurement of welding area by neutron diffraction method

    International Nuclear Information System (INIS)

    Suzuki, Tamaki; Sugiyama, Masaaki; Oikawa, Hatsuhiko; Nose, Tetsuro; Imafuku, Muneyuki; Tomota, Yo; Suzuki, Hiroshi; Moriai, Atsushi

    2010-01-01

    Resistance spot welding technique is extensively applied to join the body steel sheets in the manufacturing process for the automobile industry. It is known that the fatigue crack initiates occasionally inside of the spot-welded zone in this material, which is a serious issue of the fatigue life. Although this phenomenon is supposed to be related to internal residual stress, the actual residual stress distribution inside of the spot-welded zone is not clear up to now. In this study, a neutron diffraction residual stress measurement technique with well-defined sub-mm 3 square gauge volume is applied in order to clarify the internal three dimensional residual stress distribution just below the spot-welded part of the steel sheets. (author)

  8. Three residual income valuation methods and discounted cash flow valuation

    OpenAIRE

    Fernandez, Pablo

    2003-01-01

    In this paper we show that the three residual Income models for equity valuation always yield the same value as the Discounted Cash Flow Valuation models. We use three residual income measures: Economic Profit, Economic Value Added (EVA) and Cash Value Added. We also show that economic profit and EVA are different, although Copeland, Koller and Murrin (2000, page 55) say that economic profit is a synonym of EVA. Specifically, we first show that the present value of the Economic Profit discoun...

  9. Reduction method for residual stress of welded joint using random vibration

    International Nuclear Information System (INIS)

    Aoki, Shigeru; Nishimura, Tadashi; Hiroi, Tetsumaro

    2005-01-01

    Welded joints are used for construction of many structures. Residual stress is induced near the bead caused by locally given heat. Tensile residual stress on the surface may reduce fatigue strength. In this paper, a new method for reduction of residual stress using vibration during welding is proposed. As vibrational load, random vibration, white noise and filtered white noise are used. Two thin plates are butt-welded. Residual stress is measured with a paralleled beam X-ray diffractometer with scintillation counter after removing quenched scale chemically. It is concluded that tensile residual stress near the bead is reduced by using random vibration during welding

  10. A new spectrophotometric method for determination of residual ...

    African Journals Online (AJOL)

    Polydiallyldimethylammonium chloride (polyDADMAC) is a water-soluble cationic polyelectrolyte used for water treatment. Its residues in treated water are contaminants as they react with chlorine to produce a carcinogenic compound. Commonly-used techniques for quantification of the polycation, such as colloidal and ...

  11. Several methods applied to measuring residual stress in a known specimen

    International Nuclear Information System (INIS)

    Prime, M.B.; Rangaswamy, P.; Daymond, M.R.; Abelin, T.G.

    1998-01-01

    In this study, a beam with a precisely known residual stress distribution provided a unique experimental opportunity. A plastically bent beam was carefully prepared in order to provide a specimen with a known residual stress profile. 21Cr-6Ni-9Mn austenitic stainless steel was obtained as 43 mm square forged stock. Several methods were used to determine the residual stresses, and the results were compared to the known values. Some subtleties of applying the various methods were exposed

  12. Validation of pestice multi residue analysis method on cucumber

    International Nuclear Information System (INIS)

    2011-01-01

    In this study we aimed to validate the method of multi pesticide residue analysis on cucumber. Before real sample injection, system suitability test was performed in gas chromatography (GC). For this purpose, a sensitive pesticide mixture was used for GC-NPD and estimated the performance parameters such as number of effective theoretical plates, resolution factor, asymmetry, tailing and selectivity. It was detected that the system was suitable for calibration and sample injection. Samples were fortified at the level of 0.02, 0.2, 0.8 and 1 mg/kg with mixture of dichlorvos, malathion and chloropyrifos pesticides. In the fortification step 1 4C-carbaryl was also added on homogenized analytical portions to make use of 1 4C labelled pesticides for the determining extraction efficiency. Then the basic analytical process, such as ethyl acetate extraction, filtration, evaporation and cleanup, were performed. The GPC calibration using 1 4C- carbaryl and fortification mixture (dichlorvos, malathion and chloropyrifos) showed that pesticide fraction come through the column between the 8-23 ml fractions. The recovery of 1 4C-carbaryl after the extraction and cleanup step were 92.63-111.73 % and 74.83-102.22 %, respectively. The stability of pesticides during analysis is an important factor. In this study, stability test was performed including matrix effect. Our calculation and t test results showed that above mentioned pesticides were not stabile during sample processing in our laboratory conditions and it was found that sample comminution with dry ice may improve stability. In the other part of the study, 1 4C-chloropyrifos was used to determine homogeneity of analytical portions taken from laboratory samples. Use of 1 4C labelled pesticides allows us for quick quantification analyte, even with out clean-up. The analytical results show that after sample processing with waring blender, analytical portions were homogenous. Sample processing uncertainty depending on quantity of

  13. Measurement of residual stress in textured Al alloy by neutron diffraction method

    International Nuclear Information System (INIS)

    Okido, S.; Hayashi, M.; Tanaka, K.; Akiniwa, Y.; Minakawa, N.; Morii, Y.

    1999-01-01

    Residual stress generated in a shrunken aluminum alloy specimen, which was prepared for the round robin test conducted by VAMAS (Versailles Project on Advanced Materials and Standards) TWA-20 organized for the purpose of standardizing residual stress measurement methods, was evaluated by a neutron diffraction method. The main purpose of the round robin test was to assess the reproducibility of data obtained with the measurement facilities of the participants. The general standard of the Residual Stress Analyzer (RESA) constructed in the Japan Atomic Energy Research Institute was verified from the measured residual strains, which were equivalent to the values calculated by FEM and values measured by the research facilities in North America. Residual stress was calculated from residual strain in three perpendicular directions. The diffraction intensities were dependent on measurement directions since the prepared specimen possessed texture. Diffraction profiles in directions having a weak diffraction intensity caused an inaccurate evaluation of the residual stress. To solve this problem, a new method for evaluating residual stress with respect to diffraction plane dependency of the elastic constant was applied. The diffraction plane giving the highest intensity among 110, 200, and 220 diffraction was used to evaluate the residual strain in each of three directions. The residual strain obtained on the used diffraction plane was converted to the equivalent strain for the defined diffraction plane using the ratio of elastic constants of these two planes. The developed evaluation method achieved highly accurate measurement and remarkable efficiency in the measurement process. (author)

  14. [Method of detection of residual tissues in recurrent operations on the thyroid gland].

    Science.gov (United States)

    Gostimskiĭ, A V; Romanchishen, A F; Zaĭtseva, I V; Kuznetsova, Iu V

    2014-01-01

    A search of residual tissues is complicated in recurrent operations on the thyroid gland. The Saint-Petersburg Centre of Surgery of the Endocrine System and Oncology developed the method of detection of residual tissues of the thyroid gland with the aim of preoperative chromothyroidolymphography under control of ultrasound. The method consisted of US performance during 15-20 minutes before the operation and an introduction of 1% sterile water solution of methylene blue in revealed residual tissues of the thyroid gland. The volume of injected coloring agent was 0.5-2 ml in the residual tissue volume smaller than 9 cm3 and 2-3 ml injected in case of more than 9 cm3. The residual tissues of the thyroid gland accurately visualized during the following operation. Described method gives the possibility to detect all regions of residual tissues which should be removed and at the same time it shortens a revision and surgery trauma.

  15. CSmetaPred: a consensus method for prediction of catalytic residues.

    Science.gov (United States)

    Choudhary, Preeti; Kumar, Shailesh; Bachhawat, Anand Kumar; Pandit, Shashi Bhushan

    2017-12-22

    Knowledge of catalytic residues can play an essential role in elucidating mechanistic details of an enzyme. However, experimental identification of catalytic residues is a tedious and time-consuming task, which can be expedited by computational predictions. Despite significant development in active-site prediction methods, one of the remaining issues is ranked positions of putative catalytic residues among all ranked residues. In order to improve ranking of catalytic residues and their prediction accuracy, we have developed a meta-approach based method CSmetaPred. In this approach, residues are ranked based on the mean of normalized residue scores derived from four well-known catalytic residue predictors. The mean residue score of CSmetaPred is combined with predicted pocket information to improve prediction performance in meta-predictor, CSmetaPred_poc. Both meta-predictors are evaluated on two comprehensive benchmark datasets and three legacy datasets using Receiver Operating Characteristic (ROC) and Precision Recall (PR) curves. The visual and quantitative analysis of ROC and PR curves shows that meta-predictors outperform their constituent methods and CSmetaPred_poc is the best of evaluated methods. For instance, on CSAMAC dataset CSmetaPred_poc (CSmetaPred) achieves highest Mean Average Specificity (MAS), a scalar measure for ROC curve, of 0.97 (0.96). Importantly, median predicted rank of catalytic residues is the lowest (best) for CSmetaPred_poc. Considering residues ranked ≤20 classified as true positive in binary classification, CSmetaPred_poc achieves prediction accuracy of 0.94 on CSAMAC dataset. Moreover, on the same dataset CSmetaPred_poc predicts all catalytic residues within top 20 ranks for ~73% of enzymes. Furthermore, benchmarking of prediction on comparative modelled structures showed that models result in better prediction than only sequence based predictions. These analyses suggest that CSmetaPred_poc is able to rank putative catalytic

  16. Reduction method for residual stress of welded joint using harmonic vibrational load

    International Nuclear Information System (INIS)

    Aoki, Shigeru; Nishimura, Tadashi; Hiroi, Tetsumaro; Hirai, Seiji

    2007-01-01

    Welding is widely used for construction of many structures. Since welding is a process using locally given heat, residual stress is generated near the bead. Tensile residual stress degrades fatigue strength. Some reduction methods of residual stress have been presented and, for example, heat treatment and shot peening are practically used. However, those methods need special tools and are time consuming. In this paper, a new method for reduction of residual stress using harmonic vibrational load during welding is proposed. The proposed method is examined experimentally for some conditions. Two thin plates are supported on the supporting device and butt-welded using an automatic CO 2 gas shielded arc welding machine. Residual stress in the direction of the bead is measured by using a paralleled beam X-ray diffractometer with scintillation counter after removing quenched scale chemically. First, the welding of rolled steel for general structure for some excitation frequencies is examined. Specimens are welded along the groove on both sides. For all frequencies, tensile residual stress near the bead is significantly reduced. Second, welding of the specimen made of high tensile strength steel is examined. In this case, tensile residual stress near the bead is also reduced. Finally, the proposed method is examined by an analytical method. An analytical model which consists of mass and preloaded springs with elasto-plastic characteristic is used. Reduction of residual stress is demonstrated using this model

  17. Residual Stress Analysis in Deep Drawn Twinning Induced Plasticity (TWIP) Steels Using Neutron Diffraction Method

    Science.gov (United States)

    Hong, Seokmin; Lee, Junghoon; Lee, Sunghak; Woo, Wanchuck; Kim, Sung-Kyu; Kim, Hyoung Seop

    2014-04-01

    In Twinning Induced Plasticity (TWIP) steels, delayed fracture occurs due to residual stresses induced during deep drawing. In order to investigate the relation between residual stresses and delayed fracture, in the present study, residual stresses of deep drawn TWIP steels (22Mn-0.6C and 18Mn-2Al-0.6C steels) were investigated using the finite element method (FEM) and neutron diffraction measurements. In addition, the delayed fracture properties were examined by dipping tests of cup specimens in the boiled water. In the FEM analysis, the hoop direction residual stress was highly tensile at cup edge, and the delayed fracture was initiated by the separation of hoop direction and propagated in an axial direction. According to the neutron diffraction analysis, residual stresses in 18Mn-2Al-0.6C steel were about half the residual stresses in 22Mn-0.6C steel. From the residual strain measurement using electron back-scatter diffraction, formation of deformation twins caused a lot of grain rotation and local strain at the grain boundaries and twin boundaries. These local residual strains induce residual stress at boundaries. Al addition in TWIP steels restrained the formation of deformation twins and dynamic strain aging, resulting in more homogeneous stress and strain distributions in cup specimens. Thus, in Al-added TWIP steels, residual stress of cup specimen considerably decreased, and delayed fracture resistance was remarkably improved by the addition of Al in TWIP steels.

  18. The release of 14C-chlorsulfuron bound residue by autoclaving method and its identification

    International Nuclear Information System (INIS)

    Guo Jiangfeng; Sun Jinhe; Ye Qingfu

    1999-01-01

    When individual microorganisms were used to release bound pesticide residues, it was usually not take into full account whether the autoclaving method could lead to the release of bound residues. The soil containing bound 14 C-chlorsulfuron residues was treated with an autoclave in this study. The results reveal that the bound 14 C-chlorsulfuron residue can be released from the soil when treated with the autoclave and the release rate can be remarkably enhanced by adding water into the soil when subjected to such treatment. A TLC analysis showed that the released 14 C-residue was one of the degraded products of 14 C-chlorsulfuron. After derivatization and analysis using the GC-MS, the released 14 C-residue was tentatively identified as 2-amino-4-hydroxyl-6-methyl-1,3,5-triazine

  19. Method for Reduction of Pesticide Residue Levels in Raspberry and Blackcurrant Based on Utilization of Ozone

    Directory of Open Access Journals (Sweden)

    Balawejder Maciej

    2014-12-01

    Full Text Available The method for the reduction of pesticide residues in soft fruits based on utilization of ozone was proposed. The procedure allows for effective reduction of boscalid residues by 38% in raspberries, and about 58% thiram in blackcurrants. Furthermore, it can be used on an industrial scale.

  20. Research on measurement of residual stresses of hemispherical lithium hydride by blind-hole method

    Energy Technology Data Exchange (ETDEWEB)

    Bo, Lin, E-mail: linbo@caep.cn [China Academy of Engineering Physics, P.O. Box: 919-71, Mianyang 621900, Sichuan (China); Kaihui, He [China International Nuclear Fusion Energy Program Execution Center, 15B, Fuxing Rd, 100862 Beijing (China); Dongwei, Shan; Weicai, Yang; Yonggang, Chi; Mei, Liu; Jun, Shen [China Academy of Engineering Physics, P.O. Box: 919-71, Mianyang 621900, Sichuan (China)

    2014-04-15

    Highlights: • The residual stresses of sintered and machined lithium hydride of SR40 hyper-hemispherical and SR30 inner hemispherical sample were measured by blind-hole method. • The nearly 45 degrees direction residual stresses of SR40 hyper-hemisphere and SR30 inner hemisphere are the greatest stresses on spherical surface of lithium hydride samples. • The radial residual stress σ{sub r} of SR40 hyper-hemispherical and SR30 inner hemispherical sample is compressive stress and the circumferential residual stress σ{sub t} is tensile stress. - Abstract: The released strains of sintered and machined lithium hydride of SR40 hyper-hemispherical and SR30 inner hemispherical sample could be shown in the measuring process by blind-hole method. The residual stresses of lithium hydride sample were calculated with the formulas of residual stress and released strains. The results show that the nearly 45 degrees direction residual stresses of SR40 hyper-hemisphere and SR30 inner hemisphere are the greatest stresses on spherical surface of lithium hydride samples. The radial residual stress σ{sub r} of SR40 hyper-hemispherical and SR30 inner hemispherical sample is compressive stress and the circumferential residual stress σ{sub t} is tensile stress.

  1. Measurement of capillary permeability in canine heart determined by the tissue injection, residue detection method

    DEFF Research Database (Denmark)

    Svendsen, Jesper Hastrup; Paaske, W P; Haunsø, S

    1991-01-01

    In previous studies the tissue injection, residue detection method failed to provide results of diffusional capillary permeability comparable to those of other methods. For this reason we reconsidered the kinetic theory and found that it is necessary to take into account the apparent (restricted...... (apparent) interstitial volume of distribution, tev is the mean transit time of the indicator, and klo is the recorded fractional initial washout rate constant. In experiments on open chest dog hearts we examined capillary permeability for 51Cr-EDTA and 99mTc-DTPA with the tissue injection, residue...... detection method and the single injection, residue detection method. Blood flow was measured independently with local 133Xenon washout. D and D' were measured by a true transient diffusion method. We found that the tissue injection, residue detection method gave results for capillary extraction and Pd...

  2. Measurement of capillary permeability in canine heart determined by the tissue injection, residue detection method

    DEFF Research Database (Denmark)

    Svendsen, J H; Paaske, William P; Haunsø, S

    1991-01-01

    detection method and the single injection, residue detection method. Blood flow was measured independently with local 133Xenon washout. D and D' were measured by a true transient diffusion method. We found that the tissue injection, residue detection method gave results for capillary extraction and Pd......In previous studies the tissue injection, residue detection method failed to provide results of diffusional capillary permeability comparable to those of other methods. For this reason we reconsidered the kinetic theory and found that it is necessary to take into account the apparent (restricted...... (apparent) interstitial volume of distribution, tev is the mean transit time of the indicator, and klo is the recorded fractional initial washout rate constant. In experiments on open chest dog hearts we examined capillary permeability for 51Cr-EDTA and 99mTc-DTPA with the tissue injection, residue...

  3. Chemical analysis of solid residue from liquid and solid fuel combustion: Method development and validation

    Energy Technology Data Exchange (ETDEWEB)

    Trkmic, M. [University of Zagreb, Faculty of Mechanical Engineering and Naval Architecturek Zagreb (Croatia); Curkovic, L. [University of Zagreb, Faculty of Chemical Engineering and Technology, Zagreb (Croatia); Asperger, D. [HEP-Proizvodnja, Thermal Power Plant Department, Zagreb (Croatia)

    2012-06-15

    This paper deals with the development and validation of methods for identifying the composition of solid residue after liquid and solid fuel combustion in thermal power plant furnaces. The methods were developed for energy dispersive X-ray fluorescence (EDXRF) spectrometer analysis. Due to the fuels used, the different composition and the location of creation of solid residue, it was necessary to develop two methods. The first method is used for identifying solid residue composition after fuel oil combustion (Method 1), while the second method is used for identifying solid residue composition after the combustion of solid fuels, i. e. coal (Method 2). Method calibration was performed on sets of 12 (Method 1) and 6 (Method 2) certified reference materials (CRM). CRMs and analysis test samples were prepared in pellet form using hydraulic press. For the purpose of method validation the linearity, accuracy, precision and specificity were determined, and the measurement uncertainty of methods for each analyte separately was assessed. The methods were applied in the analysis of real furnace residue samples. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. An adjoint method of sensitivity analysis for residual vibrations of structures subject to impacts

    Science.gov (United States)

    Yan, Kun; Cheng, Gengdong

    2018-03-01

    For structures subject to impact loads, the residual vibration reduction is more and more important as the machines become faster and lighter. An efficient sensitivity analysis of residual vibration with respect to structural or operational parameters is indispensable for using a gradient based optimization algorithm, which reduces the residual vibration in either active or passive way. In this paper, an integrated quadratic performance index is used as the measure of the residual vibration, since it globally measures the residual vibration response and its calculation can be simplified greatly with Lyapunov equation. Several sensitivity analysis approaches for performance index were developed based on the assumption that the initial excitations of residual vibration were given and independent of structural design. Since the resulting excitations by the impact load often depend on structural design, this paper aims to propose a new efficient sensitivity analysis method for residual vibration of structures subject to impacts to consider the dependence. The new method is developed by combining two existing methods and using adjoint variable approach. Three numerical examples are carried out and demonstrate the accuracy of the proposed method. The numerical results show that the dependence of initial excitations on structural design variables may strongly affects the accuracy of sensitivities.

  5. Evaluation of machining effect for the residual stress of SA508 by hole drilling method

    International Nuclear Information System (INIS)

    Lee, Jeong Kun; Lee, Kyoung Soo; Song, Ki O; Kim, Young Shin

    2009-01-01

    Residual stresses on a surface of the material are welcome or undesirable since it's direction, compression or tensile. But especially for the fatigue, it is not negligible effect on the material strength. These residual stresses developed during the manufacturing processes involving material deformation, heat treatment, machining. The object of this paper is verifying the effect of machining what is mostly used for SA508. For verifying the effect of machining, three different kind of machining have been achieved, milling, grinding, wire cutting. Also to measure the residual stress, hole drill method and indentation method are used.

  6. Numerical methods for calculating thermal residual stresses and hydrogen diffusion

    International Nuclear Information System (INIS)

    Leblond, J.B.; Devaux, J.; Dubois, D.

    1983-01-01

    Thermal residual stresses and hydrogen concentrations are two major factors intervening in cracking phenomena. These parameters were numerically calculated by a computer programme (TITUS) using the FEM, during the deposition of a stainless clad on a low-alloy plate. The calculation was performed with a 2-dimensional option in four successive steps: thermal transient calculation, metallurgical transient calculation (determination of the metallurgical phase proportions), elastic-plastic transient (plain strain conditions), hydrogen diffusion transient. Temperature and phase dependence of hydrogen diffusion coefficient and solubility constant. The following results were obtained: thermal calculations are very consistent with experiments at higher temperatures (due to the introduction of fusion and solidification latent heats); the consistency is not as good (by 70 degrees) for lower temperatures (below 650 degrees C); this was attributed to the non-introduction of gamma-alpha transformation latent heat. The metallurgical phase calculation indicates that the heat affected zone is almost entirely transformed into bainite after cooling down (the martensite proportion does not exceed 5%). The elastic-plastic calculations indicate that the stresses in the heat affected zone are compressive or slightly tensile; on the other hand, higher tensile stresses develop on the boundary of the heat affected zone. The transformation plasticity has a definite influence on the final stress level. The return of hydrogen to the clad during the bainitic transformation is but an incomplete phenomenon and the hydrogen concentration in the heat affected zone after cooling down to room temperature is therefore sufficient to cause cold cracking (if no heat treatment is applied). Heat treatments are efficient in lowering the hydrogen concentration. These results enable us to draw preliminary conclusions on practical means to avoid cracking. (orig.)

  7. A Multifeatures Fusion and Discrete Firefly Optimization Method for Prediction of Protein Tyrosine Sulfation Residues.

    Science.gov (United States)

    Guo, Song; Liu, Chunhua; Zhou, Peng; Li, Yanling

    2016-01-01

    Tyrosine sulfation is one of the ubiquitous protein posttranslational modifications, where some sulfate groups are added to the tyrosine residues. It plays significant roles in various physiological processes in eukaryotic cells. To explore the molecular mechanism of tyrosine sulfation, one of the prerequisites is to correctly identify possible protein tyrosine sulfation residues. In this paper, a novel method was presented to predict protein tyrosine sulfation residues from primary sequences. By means of informative feature construction and elaborate feature selection and parameter optimization scheme, the proposed predictor achieved promising results and outperformed many other state-of-the-art predictors. Using the optimal features subset, the proposed method achieved mean MCC of 94.41% on the benchmark dataset, and a MCC of 90.09% on the independent dataset. The experimental performance indicated that our new proposed method could be effective in identifying the important protein posttranslational modifications and the feature selection scheme would be powerful in protein functional residues prediction research fields.

  8. Is residual memory variance a valid method for quantifying cognitive reserve? A longitudinal application.

    Science.gov (United States)

    Zahodne, Laura B; Manly, Jennifer J; Brickman, Adam M; Narkhede, Atul; Griffith, Erica Y; Guzman, Vanessa A; Schupf, Nicole; Stern, Yaakov

    2015-10-01

    Cognitive reserve describes the mismatch between brain integrity and cognitive performance. Older adults with high cognitive reserve are more resilient to age-related brain pathology. Traditionally, cognitive reserve is indexed indirectly via static proxy variables (e.g., years of education). More recently, cross-sectional studies have suggested that reserve can be expressed as residual variance in episodic memory performance that remains after accounting for demographic factors and brain pathology (whole brain, hippocampal, and white matter hyperintensity volumes). The present study extends these methods to a longitudinal framework in a community-based cohort of 244 older adults who underwent two comprehensive neuropsychological and structural magnetic resonance imaging sessions over 4.6 years. On average, residual memory variance decreased over time, consistent with the idea that cognitive reserve is depleted over time. Individual differences in change in residual memory variance predicted incident dementia, independent of baseline residual memory variance. Multiple-group latent difference score models revealed tighter coupling between brain and language changes among individuals with decreasing residual memory variance. These results suggest that changes in residual memory variance may capture a dynamic aspect of cognitive reserve and could be a useful way to summarize individual cognitive responses to brain changes. Change in residual memory variance among initially non-demented older adults was a better predictor of incident dementia than residual memory variance measured at one time-point. Copyright © 2015. Published by Elsevier Ltd.

  9. Analysis of residual toluene in food packaging via headspace extraction method using gas chromatography

    International Nuclear Information System (INIS)

    Lim, Ying Chin; Mohd Marsin Sanagi

    2008-01-01

    Polymeric materials are used in many food contact applications as packaging material. The presence of residual toluene in this food packaging material can migrate into food and thus affect the quality of food. In this study, a manual headspace analysis was successfully designed and developed. The determination of residual toluene was carried out with standard addition method and multiple headspace extraction, MHE) method using gas chromatography-flame ionization detector, GC-FID). Identification of toluene was performed by comparison of its retention time with standard toluene and GC-MS. It was found that the suitable heating temperature was 180 degree Celsius with an optimum heating time of 10 minutes. The study also found that the concentration of residual toluene in multicolored sample was higher compared to mono colored sample whereas residual toluene in sample analyzed using standard addition method was higher compared to MHE method. However, comparison with the results obtained from De Paris laboratory, France found that MHE method gave higher accuracy for sample with low analyte concentration. On the other hand, lower accuracy was obtained for sample with high concentration of residual toluene due to systematic errors. Comparison between determination methods showed that MHE method is more precise compared to standard addition method. (author)

  10. A comparison of residual stresses in built-up steel beams using hole-drilling method

    International Nuclear Information System (INIS)

    Nawafleh, M. A.; Hunaiti, Y. M.; Younes, R. M.

    2009-01-01

    Residual stresses have a significant effect on the stability resistance of metal building systems. An experimental program was conducted to measure these stresses in built-up steel beams using incremental hole-drilling method. The experimental results reveal that the predicted residual stress type of pattern for built-up I-sections with fillet welds on one side of the web is not the same as the pattern of residual stresses in built-up I-sections with fillet welds on both sides of the web

  11. Calculation method for residual stress analysis of filament-wound spherical pressure vessels

    International Nuclear Information System (INIS)

    Knight, C.E. Jr.

    1976-01-01

    Filament wound spherical pressure vessels may be produced with very high performance factors. These performance factors are a calculation of contained pressure times enclosed volume divided by structure weight. A number of parameters are important in determining the level of performance achieved. One of these is the residual stress state in the fabricated unit. A significant level of an unfavorable residual stress state could seriously impair the performance of the vessel. Residual stresses are of more concern for vessels with relatively thick walls and/or vessels constructed with the highly anisotropic graphite or aramid fibers. A method is established for measuring these stresses. A theoretical model of the composite structure is required. Data collection procedures and techniques are developed. The data are reduced by means of the model and result in the residual stress analysis. The analysis method can be used in process parameter studies to establish the best fabrication procedures

  12. The Method of Validity Evaluation of Hard Coal Excavation in Residual Seam Parts

    Science.gov (United States)

    Wodarski, Krzysztof; Bijańska, Jolanta; Gumiński, Adam

    2017-12-01

    The excavation of residual seam parts should be justified by positive assessment of the purposefulness, technical feasibility and economic effectiveness. The results of the profitability evaluation are crucial in a decision making process. The excavation of residual seam parts, even if it is possible from a technical point of view, should not be implemented if it is economically inefficient or when accompanied by a very high risk of non-recovery of invested capital resources. The article presents the evaluation method of possibilities of excavating hard coal from residual seam parts, and the example of its use in one of collieries in the Upper Silesian Coal Basin. Working in line with the developed method, allows to indicate the variant of residual seam part exploitation, which is feasible to implement from a technical point of view, and which is characterized by the highest economic effectiveness and lowest risk.

  13. Residual stresses in LENS[reg] components using neutron diffraction and contour method

    International Nuclear Information System (INIS)

    Rangaswamy, P.; Griffith, M.L.; Prime, M.B.; Holden, T.M.; Rogge, R.B.; Edwards, J.M.; Sebring, R.J.

    2005-01-01

    During manufacturing of components by laser engineered net shaping (LENS[reg]), a solid freeform fabrication process, the introduction of residual stresses causes deformation or in the worst case, cracking. The origin is attributed to thermal transients encountered during solidification. In the absence of reliable predictive models for the residual stresses, measurements are necessary. Residual stresses were measured in LENS[reg] samples of 316 stainless steel and Inconel 718 having simple geometrical shapes by both neutron diffraction and the contour methods. The results by the two methods are compared and discussed in the context of the growth direction during the LENS[reg] process. Surprisingly, the residual stresses are practically uni-axial, with high stresses in the growth direction

  14. A Novel Method to Decrease Micro-residual Stresses of Fibrous Composites by Adding Carbon Nanotube

    Directory of Open Access Journals (Sweden)

    M. M. Shokrieh

    2013-12-01

    Full Text Available In this research, a novel method to decrease micro-residual stresses of fibrous composites by adding carbon nanotubes (CNTs is proposed in detail. The negative coefficient of thermal expansion and the high young’s modulus of CNTs can be utilized to counterbalance the process induced residual stresses in composites. To this end, first, the effects of adding CNTs to the matrix of fibrous composites in reducing the coefficient of thermal expansion (CTE and increasing of young’s modulus of matrix are studied theoretically. Then, a three phase micromechanical model (the energy method is used to model the effect of CNT in reducing the residual stresses of fibrous composites. The results show that by addition of CNTs, enhancements in properties of matrix are obtained and lead to decrease in micro-residual stresses of matrix and fiber up to 72%.

  15. Evaluation of Antibiotic Residues in Raw Meat Using Different Analytical Methods.

    Science.gov (United States)

    Ramatla, Tsepo; Ngoma, Lubanza; Adetunji, Modupeade; Mwanza, Mulunda

    2017-12-07

    Antibiotic residue in meat is a serious public health concern due to its harmful effects on consumer health. This study aimed at estimating the residue levels of four commonly used antibiotics in meat samples using three analytical methods (ELISA, TLC and HPLC). A total of 150 samples of raw meat from sales points were analysed for ciprofloxacin, streptomycin, tetracycline, and sulphanilamide residues. Overall, ELISA analysis showed that 56, 34, 18, and 25.3% of the samples tested positive for ciprofloxacin, streptomycin, sulphanilamide and tetracycline residues respectively while TLC and HPLC detected 21.4, 29.4, 92.5, and 14.6%, and 8.3, 41.1, 88.8, and 14.6% of the samples as containing the residues, with ciprofloxacin and sulphanilamide having the lowest and highest occurrence, respectively. Furthermore, the concentrations of antibiotic residues were in the ranges of 19.8-92.8, 26.6-489.1, 14.2-1280.8, and 42.6-355.6 μg/kg with ELISA, while HPLC detected concentration ranges of 20.7-82.1, 41.8-320.8, 65.2-952.2 and 32.8-95.6 μg/kg for sulphanilamide, tetracycline, streptomycin, and ciprofloxacin, respectively. Mean ciprofloxacin and streptomycin residue levels were above the Codex/SA MRL recommended limit, while 3% of the samples contained multidrug residues. Although some of the mean residues levels were below the permissible limits, the co-occurrence of multidrug residues in some of the samples calls for concern.

  16. Feasibility of ultrasonic and eddy current methods for measurement of residual stress in shot peened metals

    International Nuclear Information System (INIS)

    Lavrentyev, Anton I.; Stucky, Paul A.; Veronesi, William A.

    2000-01-01

    Shot peening is a well-known method for extending the fatigue life of metal components by introducing compressive residual stresses near their surfaces. The capability to nondestructively evaluate the near surface residual stress would greatly aid the assurance of proper fatigue life in shot-peened components. This paper presents preliminary results from a feasibility study examining the use of ultrasonic and eddy current NDE methods for residual stress measurement in components where the stress has been introduced by shot peening. With an ultrasonic method, a variation of ultrasonic surface wave speed with shot peening intensity was measured. Near surface conductivity was measured by eddy current methods. Since the effective penetration depth of both methods employed is inversely related to the excitation frequency, by making measurements at different frequencies, each method has the potential to provide the stress-depth profile. Experiments were conducted on aluminum specimens (alloy 7075-T7351) peened within the Almen peening intensity range of 4C to 16C. The experimental results obtained demonstrate a correlation between peening intensity and Rayleigh wave velocity and between peening intensity and conductivity. The data suggests either of the methods may be suitable, with limitations, for detecting unsatisfactory levels of shot peening. Several factors were found to contribute to the measured responses: surface roughness, near surface plastic deformation (cold work) and residual stress. The contribution of each factor was studied experimentally. The feasibility of residual stress determination from the measured data is discussed

  17. Residual stress measurement of large scaled welded pipe using neutron diffraction method. Effect of SCC crack propagation and repair weld on residual stress distribution

    International Nuclear Information System (INIS)

    Suzuki, Hiroshi; Katsuyama, Jinya; Tobita, Tohru; Morii, Yukio

    2011-01-01

    The RESA-1 neutron engineering diffractometer in the JRR-3 (Japan Research Reactor No.3) at the Japan Atomic Energy Agency, which is used for stress measurements, was upgraded to realize residual stress measurements of large scaled mechanical components. A series of residual stress measurements was made to obtain through-thickness residual stress distributions in a Type 304 stainless steel butt-welded pipe of 500A-sch.80 using the upgraded RESA-1 diffractometer. We evaluated effects of crack propagation such as stress corrosion cracking (SCC) and a part-circumference repair weld on the residual stress distributions induced by girth welding. Measured residual stress distributions near original girth weld revealed good agreement with typical results shown in some previous works using finite element method, deep hole drilling as well as neutron diffraction. After introducing a mock crack with 10 mm depth in the heat affected zone on the inside wall of the pipe by electro discharge machining, the axial residual stresses were found to be released in the part of the mock crack. However, changes in the through-wall bending stress component and the self-equilibrated stress component were negligible and hence the axial residual stress distribution in the ligament was remained in the original residual stresses near girth weld without the mock crack. Furthermore, changes in hoop and radial residual stress were also small. The residual stress distributions after a part repair welding on the outer circumference of the girth weld were significantly different from residual stress distributions near the original girth weld. The through-thickness average axial residual stress was increased due to increase of the tensile membrane stress and mitigation of the bending stress after repair welding. Throughout above studies, we evidenced that the neutron diffraction technique is useful and powerful tool for measuring residual stress distributions in large as well as thick mechanical

  18. Residual power series method for fractional Sharma-Tasso-Olever equation

    Directory of Open Access Journals (Sweden)

    Amit Kumar

    2016-02-01

    Full Text Available In this paper, we introduce a modified analytical approximate technique to obtain solution of time fractional Sharma-Tasso-Olever equation. First, we present an alternative framework of the Residual power series method (RPSM which can be used simply and effectively to handle nonlinear fractional differential equations arising in several physical phenomena. This method is basically based on the generalized Taylor series formula and residual error function. A good result is found between our solution and the given solution. It is shown that the proposed method is reliable, efficient and easy to implement on all kinds of fractional nonlinear problems arising in science and technology.

  19. Prevalence of antibiotic residues in commercial milk and its variation by season and thermal processing methods

    Directory of Open Access Journals (Sweden)

    Fathollah Aalipour

    2013-01-01

    Full Text Available Aims: In this study, the prevalence of antibiotic residues in pasteurized and sterilized commercial milk available in Shahre-kourd, Iran, was investigated. In addition, the influence of seasonal temperature changes on the prevalence of contamination was studied. Materials and Methods: Commercial milk samples of 187, including 154 pasteurized and 33 sterilized, milk samples were collected from the market between early January 2012 and late July of the same year. The presence of antibiotic residues was detected using the microbiological detection test kit, Eclipse 100, as a semi-quantitative method. Results: The results showed that 37 of the samples (19.8% have contained antibiotic residues above the European Union Maximum Residues Limits (EU-MRLs, of which 28 samples (14.97% were found to be contaminated but at the concentrations below the EU-MRLs. There was no significant difference between the contamination rate of pasteurized and Ultra High Temperature (UHT-sterilized samples. Similarly, variation of weather temperature with seasons had no effect on the contamination prevalence of milk samples ( P > 0.05. Conclusion: Based on the result of this study, antibiotics residues were present in the majority of milk samples. Neither the season nor the type of thermal processing of the commercial milks had noticeable impact on the prevalence level of the milk samples. However, an increasing trend of prevalence level for antibiotic residues was observed with increasing the temperature through the warm season.

  20. A method to evaluate residual phase error for polar formatted synthetic aperture radar systems

    Science.gov (United States)

    Musgrove, Cameron; Naething, Richard

    2013-05-01

    Synthetic aperture radar systems that use the polar format algorithm are subject to a focused scene size limit inherent to the polar format algorithm. The classic focused scene size limit is determined from the dominant residual range phase error term. Given the many sources of phase error in a synthetic aperture radar, a system designer is interested in how much phase error results from the assumptions made with the polar format algorithm. Autofocus algorithms have limits to the amount and type of phase error that can be corrected. Current methods correct only one or a few terms of the residual phase error. A system designer needs to be able to evaluate the contribution of the residual or uncorrected phase error terms to determine the new focused scene size limit. This paper describes a method to estimate the complete residual phase error, not just one or a few of the dominant residual terms. This method is demonstrated with polar format image formation, but is equally applicable to other image formation algorithms. A benefit for the system designer is that additional correction terms can be added or deleted from the analysis as necessary to evaluate the resulting effect upon image quality.

  1. The gravimetric method for the determination of residual moisture in freeze-dried biological products.

    Science.gov (United States)

    May, J C; Wheeler, R M; Grim, E

    1989-06-01

    The gravimetric test for the determination of residual moisture in freeze-dried biological products performed in a humidity- and temperature-controlled room with the use of scrupulous gravimetric analytical technique can be used to accurately determine residual moisture in freeze-dried biological products such as antihemophilic factor (human) or honey bee venom allergenic extract. This method determines the first water of hydration of sodium tartrate dihydrate (7.93%) to within 1.3% of the calculated value with a relative standard deviation of 0.3% for 10 replicates. For this gravimetric procedure, freeze-dried samples containing from 1.12 to 4.4% residual moisture had relative standard deviations ranging from 3.6 to 9.1%. Samples containing less than 1.0% residual moisture by the gravimetric method such as intravenous immune globulin and antihemophilic factor (human) had relative standard deviations ranging from 16.7 to 47.0%. Relative standard deviations for residual moisture tests performed on comparable samples by the Karl Fischer and thermogravimetric methods showed similar variability.

  2. Multi-residue methods for confirmatory determination of antibiotics in milk.

    Science.gov (United States)

    Samanidou, Victoria; Nisyriou, Styliani

    2008-06-01

    The prevalent use of antibiotics, e. g. sulphonamides, tetracyclines, beta-lactams, macrolides, aminoglycosides, etc., in dairy farming to prevent and treat microbial infections e. g. mastitis, can be a potential source of veterinary drug residues in milk. Antibiotic residues constitute a risk to human health, since they can cause allergic reactions in hypersensitive individuals or they may lead to the appearance of drug-resistant bacteria. Analysis of these residues plays a key role in ensuring food safety. Regulatory agencies in the European Union and in other countries have established maximum residue limits and requirements concerning the performance of analytical methods and the interpretation of the results. This review describes the state of the art in the analytical strategies concerning the multi-class as well as the multi-residue analysis of antibiotics in milk. Since milk is a complex matrix due to its high protein and fat content, which often interfere in analytical procedures, special focus has been placed on sample preparation: extraction and clean-up. Confirmation of antibiotic residues according to European Decision 657/2002/EC has been also discussed.

  3. Determination of Profenofos Pesticidal Residue in Lettuce (Lactuca sativa L. by Gas Chromatographic Method

    Directory of Open Access Journals (Sweden)

    Yohannes Alen

    2015-05-01

    Full Text Available The determination of profenofos pesticidal residue in the lettuce (Lactuca sativa L. by using gas chromatography using flame photometric detector (FPD had been investigated. The lettuce was collected from Padang Luar area, Agam distric, West Sumatera. Sample for determination of profenofos residue divided into three groups: unwashed (A, washed with water (B, and washed with detergent (C. Maceration with sonication was used for the extraction using ethylacetateas a solvent. The results showed that profenofos pesticide residue in sample A, B and C were 0.204, 0.080 and 0.061 ppm, respectively. These profenofos pesticidal residue are over than the Maximum Residue Limits (MRL that established by The Japan Food Chemical Research Foundation (0.05 ppm even though World Health Organization (WHO has not established Maximum Residue Limits (MRL profenofos on lettuce. Based on the statistical analysis one-way method (Anova using SPSS 20.0 showed that there was a significant concentrations difference between lettuce A from lettuce B and lettuce C with p < 0.05.

  4. Fast multipole accelerated boundary element method for the Helmholtz equation in acoustic scattering problems

    Science.gov (United States)

    Li, ShanDe; Gao, GuiBing; Huang, QiBai; Liu, WeiQi; Chen, Jun

    2011-08-01

    We apply the fast multipole method (FMM) accelerated boundary element method (BEM) for the three-dimensional (3D) Helmholtz equation, and as a result, large-scale acoustic scattering problems involving 400000 elements are solved efficiently. This is an extension of the fast multipole BEM for two-dimensional (2D) acoustic problems developed by authors recently. Some new improvements are obtained. In this new technique, the improved Burton-Miller formulation is employed to overcome non-uniqueness difficulties in the conventional BEM for exterior acoustic problems. The computational efficiency is further improved by adopting the FMM and the block diagonal preconditioner used in the generalized minimum residual method (GMRES) iterative solver to solve the system matrix equation. Numerical results clearly demonstrate the complete reliability and efficiency of the proposed algorithm. It is potentially useful for solving large-scale engineering acoustic scattering problems.

  5. Residual nitrogen-15 recovery by corn as influenced by tillage and fertilization method

    International Nuclear Information System (INIS)

    Timmons, D.R.; Cruse, R.M.

    1991-01-01

    Tillage systems that create different surface residue conditions may also affect the recovery of residual fertilizer N during subsequent growing seasons. This study evaluated the recovery of residual labeled N fertilizer in the soil by corn (Zea mays L.) for two tillage systems and two fertilization methods. Five atom % 15 N-enriched 28% urea-ammonium nitrate solution (UAN) at 224 kg N ha -1 was either surface-applied in the fall before any primary tillage or banded (knifed in) just before planting in the spring. Continuous corn was grown with either fall moldboard-plow (MP) or ridge-till (RT) systems. After the initial growing season, the recovery of residual labeled N in the soil by corn was determined for three consecutive growing seasons, and the soil profile was sampled periodically to measure residual 15 N in the organic and inorganic pools. One year after labeled UAN application, from 16 to 27% of the initial 15 N applied was found in the organic N pool and only 1% as inorganic N[NH 4 +(NO 2 +NO 3 )-N]. After four seasons, residual 15 N in the organic N pool ranged from 13 to 24%. Less than 0.5% remained as inorganic N. Regression analyses indicated that about 5 kg 15 N ha -1 year -1 became available for both MP and RT systems with banded N, so the amounts were small. Total residual 15 N recovery by corn grain plus stover for three seasons ranged from 1.7 to 3.5%, and was greatest for spring-banded fertilizer. Because the amounts of residual 15 N utilized were too small to affect corn growth, this N source appears to be negligible when considering corn-N needs

  6. Evaluation of Methods for the Calculation of the pKa of Cysteine Residues in Proteins.

    Science.gov (United States)

    Awoonor-Williams, Ernest; Rowley, Christopher N

    2016-09-13

    Methods for the calculation of the pKa ionizable amino acids are valuable tools for understanding pH-dependent properties of proteins. Cysteine is unique among the amino acids because of the chemical reactivity of its thiol group (S-H), which plays an instrumental role in several biochemical and regulatory functions. The acidity of noncatalytic cysteine residues is a factor in their susceptibility to chemical modification. Despite the plethora of existing pKa computing methods, no definitive protocol exists for accurately calculating the pKa's of cysteine residues in proteins. A cysteine pKa test set was developed, which is comprised of 18 cysteine residues in 12 proteins where the pKa's have been determined experimentally and an experimental structure is available. The pKa's of these residues were calculated using three methods that use an implicit solvent model (H++, MCCE, and PROPKA) and an all-atom replica-exchange thermodynamic integration approach with the CHARMM36 and AMBER ff99SB-ILDNP force fields. The models that use implicit solvation methods were generally unreliable in predicting cysteine residue pKa's, with RMSDs between 3.41 and 4.72 pKa units. On average, the explicit solvent methods performed better than the implicit solvent methods. RMSD values of 2.40 and 3.20 were obtained for simulations with the CHARMM36 and AMBER ff99SB-ILDNP force fields, respectively. Further development of these methods is necessary because the performance of the best method is similar to that of the null-model (RMSD = 2.74) and these differences in RMSD are of limited statistical significance given the small size of our test set.

  7. Qualitative screening method for pesticide residues detection in fruits and vegetables

    Directory of Open Access Journals (Sweden)

    Iván Mauricio Huérfano Barco

    2018-01-01

    Full Text Available Because of the importance of developing methodologies that allow agricultural residues analysis, a rapid screening qualitative method for the determination of pesticides residues in fruits and vegetables was validated. The methodology was based on the European QuEChERS extraction method with an additional cleaning step by gel permeation chromatography (GPC, which helped to reduce the number of matrix components in the final extract. The analysis was carried out by gas chromatography coupled to mass spectrometry with a single quadrupole analyzer. The methodology was appropriate for the qualitative analysis of 31 pesticides at their respective maximum residue limits. Consistent results were obtained with respect to a quantitative routine methodology in the analysis of real samples, hence the methodology was proven to be a good alternative for the fast analysis of these contaminants in fruits and vegetables.

  8. Residues of Eight Antibiotics in Vegetable Soils Affected by Fertilization Methods

    Directory of Open Access Journals (Sweden)

    BAO Chen-yan

    2014-08-01

    Full Text Available Total forty-four representative soil samples were collected from vegetable fields in Hangzhou, Jiaxing, and Shaoxing city of Zhe-jiang Province for measuring concentrations of eight antibiotics, including chloroteracycline, tetracycline, oxytetracyline, enrofloxacin, sulfa-diazine, sulfamethazine, sulfamethoxazole, and tylosin. Effects of four fertilization methods(application of livestock and poultry manure, appli-cation of commercial organic fertilizer, application of biogas residue and application of chemical fertilizeron residues of the antibiotics in the soils were investigated. The results showed that the detection proportions and concentrations of the antibiotics in the soils varied with appli-cation methods of fertilizers and species of antibiotics. The concentration of chloroteracycline in the soils was much higher than those of other antibiotics. Mean percentage proportion of chloroteracycline in total residues of eight antibiotics was 67.03%. The detection proportions and concentrations of the antibiotics decreased in the sequence of chloroteracycline>sulfamethazine>enrofloxacin>tetracycline>sulfamethoxazole, tylosin>oxytetracycline>sulfadiazine. The detection proportion and concentration of the tetracyclines were greater than those of the sulfon-amides. The residues of the antibiotics in the soils applied with livestock and poultry manure were much greater than those of other vegetable soils, and the detection proportions and concentrations of the antibiotics in the soils decreased in the sequence of fields with application of livestock and poultry manure>fields with application of commercial organic fertilizer>fields with application of biogas residue>fields with ap-plication of chemical fertilizer. The results indicate that the livestock and poultry manure is the main source of antibiotics in vegetable soils, and application of commercial organic fertilizer and biogas residue also have certain contribution to antibiotics residues

  9. On the residual stress modeling of shot-peened AISI 4340 steel: finite element and response surface methods

    Science.gov (United States)

    Asgari, Ali; Dehestani, Pouya; Poruraminaie, Iman

    2018-02-01

    Shot peening is a well-known process in applying the residual stress on the surface of industrial parts. The induced residual stress improves fatigue life. In this study, the effects of shot peening parameters such as shot diameter, shot speed, friction coefficient, and the number of impacts on the applied residual stress will be evaluated. To assess these parameters effect, firstly the shot peening process has been simulated by finite element method. Then, effects of the process parameters on the residual stress have been evaluated by response surface method as a statistical approach. Finally, a strong model is presented to predict the maximum residual stress induced by shot peening process in AISI 4340 steel. Also, the optimum parameters for the maximum residual stress are achieved. The results indicate that effect of shot diameter on the induced residual stress is increased by increasing the shot speed. Also, enhancing the friction coefficient magnitude always cannot lead to increase in the residual stress.

  10. RSARF: Prediction of residue solvent accessibility from protein sequence using random forest method

    KAUST Repository

    Ganesan, Pugalenthi

    2012-01-01

    Prediction of protein structure from its amino acid sequence is still a challenging problem. The complete physicochemical understanding of protein folding is essential for the accurate structure prediction. Knowledge of residue solvent accessibility gives useful insights into protein structure prediction and function prediction. In this work, we propose a random forest method, RSARF, to predict residue accessible surface area from protein sequence information. The training and testing was performed using 120 proteins containing 22006 residues. For each residue, buried and exposed state was computed using five thresholds (0%, 5%, 10%, 25%, and 50%). The prediction accuracy for 0%, 5%, 10%, 25%, and 50% thresholds are 72.9%, 78.25%, 78.12%, 77.57% and 72.07% respectively. Further, comparison of RSARF with other methods using a benchmark dataset containing 20 proteins shows that our approach is useful for prediction of residue solvent accessibility from protein sequence without using structural information. The RSARF program, datasets and supplementary data are available at http://caps.ncbs.res.in/download/pugal/RSARF/. - See more at: http://www.eurekaselect.com/89216/article#sthash.pwVGFUjq.dpuf

  11. Asymptotic Solutions of Time-Space Fractional Coupled Systems by Residual Power Series Method

    Directory of Open Access Journals (Sweden)

    Wenjin Li

    2017-01-01

    Full Text Available This paper focuses on the asymptotic solutions to time-space fractional coupled systems, where the fractional derivative and integral are described in the sense of Caputo derivative and Riemann-Liouville integral. We introduce the Residual Power Series (for short RPS method to construct the desired asymptotic solutions. Furthermore, we apply this method to some time-space fractional coupled systems. The simplicity and efficiency of RPS method are shown by the application.

  12. Fibonacci collocation method with a residual error Function to solve linear Volterra integro differential equations

    Directory of Open Access Journals (Sweden)

    Salih Yalcinbas

    2016-01-01

    Full Text Available In this paper, a new collocation method based on the Fibonacci polynomials is introduced to solve the high-order linear Volterra integro-differential equations under the conditions. Numerical examples are included to demonstrate the applicability and validity of the proposed method and comparisons are made with the existing results. In addition, an error estimation based on the residual functions is presented for this method. The approximate solutions are improved by using this error estimation.

  13. Photography - Determination of thiosulphate and other residual chemicals in processed photographic films, plates and papers - Methylene blue photometric method and silver sulphide densitometric method

    CERN Document Server

    International Organization for Standardization. Geneva

    1977-01-01

    Photography - Determination of thiosulphate and other residual chemicals in processed photographic films, plates and papers - Methylene blue photometric method and silver sulphide densitometric method

  14. Development of nondestructive hybrid measuring method for three-dimensional residual stress distribution of thick welded joint. Hybrid measuring method of inherent strain method and neutron diffraction method

    International Nuclear Information System (INIS)

    Nakacho, Keiji; Kasahara, Norifumi; Tamura, Ryota

    2012-01-01

    The measuring methods of the residual stress are classified into destructive one and nondestructive one. The inherent strain method (ISM) is destructive one. The neutron diffraction method (NDM) is nondestructive one. But the measurable depth is limited within about 20 mm and the method cannot measure the weld zone, without destruction of the object. So, in this study, the hybrid measuring method has been developed, by combining the ISM and the NDM. The theory of the hybrid method is the same as the ISM. In the analysis, the strains measured by the NDM without destruction are used. This hybrid measuring method is a true nondestructive measuring method for a thick welded joint. The applicability of the hybrid method has been verified by simulation, using a butt welded joint of thick pipes. In the simulation, the reliable order of the strains measured by the present NDM is very important, and was considered as 10 micro. The measurable regions by the present NDM were assumed. Under the above conditions, the data (the residual elastic strains assumed to be measured by the NDM) were made, and used in the ISM. As a result of such simulation, it has been cleared that the estimated residual stress has very high accuracy, if enough data are used. The required number of data is less than the ISM. (author)

  15. Effect of depth of planting, methods of planting and animal residues ...

    African Journals Online (AJOL)

    This study was carried out in farmers' field, from March to December in 2014 and 2015 cropping seasons at the research site of the Lower Niger River Basin Development Authority, Ejiba, Kogi State of Nigeria to investigate the effect of depth of planting, methods of planting and animal residues application on the growth and ...

  16. A method for computing the inter-residue interaction potentials for ...

    Indian Academy of Sciences (India)

    PRAKASH KUMAR

    2007-06-16

    Jun 16, 2007 ... [Luthra A, Jha A N, Ananthasuresh G K and Vishveswara S 2007 A method for computing the inter-residue interaction potentials for reduced amino acid alphabet; J. ... Therefore, a systematic approach to this problem is warranted so ... chemical and biological or quantitative measures are used. Dayhoff et al ...

  17. Nouws antibiotics test: Validation of a post-screening method for antibiotic residues in kidney

    NARCIS (Netherlands)

    Pikkemaat, M.G.; Oostra-van Dijk, S.; Schouten, J.; Rapallini, M.; Kortenhoeven, L.; Egmond, van H.J.

    2009-01-01

    Anticipating the rise in ‘suspect’ samples caused by the introduction of a more sensitive screening test for the presence of antibiotic residues in slaughter animals, an additional microbial post-screening method was developed. The test comprises four antibiotic group specific test plates, optimized

  18. Apparatus and method for rapid detection of explosives residue from the deflagration signature thereof

    Science.gov (United States)

    Funsten, H.O.; McComas, D.J.

    1999-06-15

    Apparatus and method are disclosed for rapid detection of explosives residue from the deflagration signature thereof. A property inherent to most explosives is their stickiness, resulting in a strong tendency of explosive particulate to contaminate the environment of a bulk explosive. An apparatus for collection of residue particulate, burning the collected particulate, and measurement of the ultraviolet emission produced thereby, is described. The present invention can be utilized for real-time screening of personnel, cars, packages, suspected devices, etc., and provides an inexpensive, portable, and noninvasive means for detecting explosives. 4 figs.

  19. Acceleration of step and linear discontinuous schemes for the method of characteristics in DRAGON5

    Directory of Open Access Journals (Sweden)

    Alain Hébert

    2017-09-01

    Full Text Available The applicability of the algebraic collapsing acceleration (ACA technique to the method of characteristics (MOC in cases with scattering anisotropy and/or linear sources was investigated. Previously, the ACA was proven successful in cases with isotropic scattering and uniform (step sources. A presentation is first made of the MOC implementation, available in the DRAGON5 code. Two categories of schemes are available for integrating the propagation equations: (1 the first category is based on exact integration and leads to the classical step characteristics (SC and linear discontinuous characteristics (LDC schemes and (2 the second category leads to diamond differencing schemes of various orders in space. The acceleration of these MOC schemes using a combination of the generalized minimal residual [GMRES(m] method preconditioned with the ACA technique was focused on. Numerical results are provided for a two-dimensional (2D eight-symmetry pressurized water reactor (PWR assembly mockup in the context of the DRAGON5 code.

  20. Characteristic and principle of the residual stress measurement by neutron diffraction method

    International Nuclear Information System (INIS)

    Akiniwa, Yoshiaki

    2016-01-01

    Although X-ray method has been widely used as the nondestructive measurement method of residual stress, the object to be measured with laboratory X-ray was limited to the vicinity of surface, and the nondestructive measurement of stress inside an essential component could not be performed. Since the neutron method utilizes the wave characteristics of electrically neutral particles, the penetrability is excellent so that information up to the inside of a material can be obtained sufficiently. As the feature of neutron stress measurement, it is suitable for measurement inside metals such as iron and aluminum, which cannot be measured with X-rays. For the measurement of residual stress in localized region, the use of high energy synchrotron radiation is advantageous. In the stress measurement utilizing diffraction phenomena, there is the strain calculated from a change in diffraction lattice spacing. The measured strain is converted into stress using Hooke's Law. As the measurement examples of neutron stress evaluation, the following are introduced: (1) residual stress distribution around the ferrite steel (50 mm thick) welded joint of a large-sized structure, (2) residual stress due to the heat treatment of aluminum alloy with a plate thickness of 20 to 140 mm, and (3) change in the strain of aluminum die block in the vicinity of a cast iron cylinder liner of engine, when heating/cooling up to 470degC. (A.O.)

  1. Vest-over-Pant Method for Closure of Residual Cavity of Liver Hydatid Cyst

    Directory of Open Access Journals (Sweden)

    Saba Behdad

    2012-01-01

    Full Text Available Objective. Although several therapeutic strategies have proven to be effective for hydatid cyst of liver, but surgery is still the most common therapy despite its morbidity and mortality. Furthermore, a variety of technique has been recommended for managing the residual cavity after cystectomy. We report here a new technical method for the reconstruction of hydatid cyst residual cavity with using overlapping flaps of liver edges (Vest over Pant. Methods. In this technique after removing the cyst, the edges of one side of cyst cavity were sutured to the base of the cavity using three to four mattress sutures, and edges of other side of liver was overlapped on the dorsal part of previous layer using four to five mattress sutures. Therefore residual cavity dead space was obliterated with two surfaces of cavity. Results. Fifty males were treated by our method. The average cyst volume was 423±110 mL. There was no intraabdominal sepsis, bile leakage, or hepatic necrosis. In follow-up ultrasound study, residual cavities were disappeared one month after operation. Conclusion. Overlapping flaps of liver edges (Vest over Pant provides easy, safe closure of cyst with preservation of the liver anatomy.

  2. Cmrh

    Science.gov (United States)

    Sadok, H.

    1999-08-01

    The Generalized Minimal Residual (GMRES) method and the Quasi-Minimal Residual (QMR) method are two Krylov methods for solving linear systems. The main difference between these methods is the generation of the basis vectors for the Krylov subspace. The GMRES method uses the Arnoldi process while QMR uses the Lanczos algorithm for constructing a basis of the Krylov subspace. In this paper we give a new method similar to QMR but based on the Hessenberg process instead of the Lanczos process. We call the new method the CMRH method. The CMRH method is less expensive and requires slightly less storage than GMRES. Numerical experiments suggest that it has behaviour similar to GMRES.

  3. Residual stress evaluation in the vicinity of ceramic coating interface using polychromatic X-ray method

    Energy Technology Data Exchange (ETDEWEB)

    Shibano, Jun-ichi; Ukai, Takayoshi; Tadano, Shigeru [Hokkaido Univ., Sapporo (Japan). Faculty of Engineering; Todoh, Masahiro

    1995-06-01

    This paper presents a polychromatic X-ray method for nondestructive evaluation of residual stress distributed in the vicinity of the interface between a ceramic coating layer and a substrate metal. Since the strain is assumed to be a linear function of the depth, the strain distribution along the depth direction can be obtained from the weighted mean strain equation calculated by considering the intensity of diffracted X-rays over the penetration depth. Therefore, the distribution along the depth direction of the residual stress was determined by the strain distributions in two directions: the vertical direction and the inclined direction to the surface. SUS316 coated with TiN by the PVD process was used as the specimen. The residual stress distributions in the coating layer and the substrate of the specimen were evaluated using this method. As a result, not only compressive residual stress in the coating layer but also the stress gradient in the substrate could be confirmed simultaneously and nondestructively. (author).

  4. Reliability residual-life prediction method for thermal aging based on performance degradation

    International Nuclear Information System (INIS)

    Ren Shuhong; Xue Fei; Yu Weiwei; Ti Wenxin; Liu Xiaotian

    2013-01-01

    The paper makes the study of the nuclear power plant main pipeline. The residual-life of the main pipeline that failed due to thermal aging has been studied by the use of performance degradation theory and Bayesian updating methods. Firstly, the thermal aging impact property degradation process of the main pipeline austenitic stainless steel has been analyzed by the accelerated thermal aging test data. Then, the thermal aging residual-life prediction model based on the impact property degradation data is built by Bayesian updating methods. Finally, these models are applied in practical situations. It is shown that the proposed methods are feasible and the prediction accuracy meets the needs of the project. Also, it provides a foundation for the scientific management of aging management of the main pipeline. (authors)

  5. A Straight-Line Method for Analyzing Residual Drawdowns at an Observation Well

    Directory of Open Access Journals (Sweden)

    Mesut Çimen

    2015-01-01

    Full Text Available Determination of the hydraulic parameters (transmissivity and storage coefficients of a confined aquifer is important for effective groundwater resources. For this purpose, the residual drawdowns have been in use to estimate the aquifer parameters by the classical Theis recovery method. The proposed method of this paper depends on a straight-line through the field data and it helps to calculate the parameters quickly without any need for long-term pumping data. It is based on the expansion series of the Theis well function by consideration of three terms, and this approach is valid for the dimensionless time factor u′=S′r2/4Tt′≤0.2. The method can be applied reliably to extensive and homogeneous confined aquifers resulting in different storage coefficients during the pumping and recovery periods S≠S′. It presents a strength methodology for the parameters decision making from the residual data in the groundwater field of civil engineering.

  6. [Development of analytical methods for residual N-methyl carbamate pesticides in foods].

    Science.gov (United States)

    Goto, Tomomi

    2010-08-01

    One of the major roles of public health agencies is to ensure safe products for consumers through analysis of residual agricultural chemicals and veterinary drugs in foods. The use of agricultural chemicals and veterinary drugs in agriculture is necessary to improve the quality of the food produced. They play a beneficial role in providing a plentiful, low-cost supply of high-quality food. On the other hand, as a consequence of this use, the presence of residues in food that is a critical element of overall public health is unavoidable, and residues in food are of great importance in the evaluation of food quality. N-methyl carbamate pesticides have anticholinesterase activity and are used worldwide. The postcolumn HPLC method is widely used for the detection of N-methyl carbamate pesticides in food. However, this traditional method involves a time-consuming process that requires skillful techniques. Therefore we developed a new analysis method for N-methyl carbamate pesticides as described in detail in this paper. The new method, including sample preparation and determination, is simple and rapid and allows simultaneous determination of pesticides in food within a much shorter analysis time as compared with the traditional method. This should provide high-quality analysis and ensure safe products for consumers.

  7. Moxidectin residues in lamb tissues: Development and validation of analytical method by UHPLC-MS/MS.

    Science.gov (United States)

    Del Bianchi A Cruz, Michelle; Fernandes, Maria A M; de C Braga, Patricia A; Monteiro, Alda L G; Daniel, Daniela; Reyes, Felix G R

    2018-01-01

    The development and validation of a throughput method for the quantitation of moxidectin residues in lamb target tissues (muscle, kidney, liver and fat) was conducted using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). To achieve higher recovery of the analyte from the matrices, a modified QuEChERS method was used for sample preparation. The chromatographic separation was achieved using a Zorbax Eclipse Plus C18 RRHD column with a mobile phase comprising 5mM ammonium formate solution +0.1% formic acid (A) and acetonitrile +0.1% formic acid (B) in a linear gradient program. Method validation was performed based on the Commission Decision 2002/657/EC and VICH GL49. To quantify the analyte, matrix-matched analytical curves were constructed with spiked blank tissues, with a limit of quantitation of 5ngg -1 and limit of detection of 1.5ngg -1 for all matrices. The linearity, decision limit, detection capability accuracy, and inter- and intra-day repeatability of the method are reported. The method was successfully applied to incurred lamb tissue samples (muscle, liver, kidney and fat) in a concentration range from 5 to 200μgkg -1 , which demonstrated its suitability for monitoring moxidectin residues in lamb tissues in health surveillance programs, as well as for pharmacokinetics and residue depletion studies. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Development of an analytical method for determination of sulfonamide residues in eggs

    International Nuclear Information System (INIS)

    Ben Azzeddine, Chams

    2009-01-01

    For the determination of sulfonamide residues in eggs, Premitest is selected for screening, providing a qualitative biological approach, it is inexpensive, fast, multi-elements and easy to implement. The H. P.L.C. / UV is the quantitative method of choice for confirmation and determination of these contaminants. During my internship, I had the opportunity to participate in the development of this method. It is recognized slower and more expensive but more specific and more sensitive. In this report, I present this optimized method and some criteria checked during my internship. Other criteria are to be completed to validate the method that will be subsequently used for routine analysis.

  9. Application of the bead flush method to welded pipes to evaluate residual stresses nondestructively

    International Nuclear Information System (INIS)

    Nakamura, H.; Yamamoto, M.

    2002-01-01

    To assess the structural integrity of welded structures during the design and in-service inspection, it is important to evaluate welding residual stresses. Recently, the design process of structures has shifted from 'the design by rule' to 'the design by analysis' using the FEM (finite element method) codes. As the design process advances, analytical processes have formed a link in the chain of manufacturing and in-service inspection procedures. Under this circumstance, authors have proposed a new method called 'the Bead Flush Method', to evaluate the welding residual stresses by utilizing the FEM data constructed during the structural design. In this method, eigenstrains as sources of residual stresses are calculated from released elastic strains after removal of reinforcement of the weld by applying the inverse analysis. Then, residual stresses as well as displacements at any location concerned are evaluated by imposing eigenstrains as initial strains in the FEM analysis. Mechanical properties required through this analysis are the elastic constants at room temperature. No further properties, such as temperature dependencies of the yield strength and the thermal coefficient, are needed. By now, we have confirmed its utility for welded plates by computer simulations and experiments. In this study, further development of this method for application to welded pipes was attempted. Despite its relatively simple shape of pipes (axe symmetrical) compared with welded plates (3-dimentional), welded pipe problems are more complicated than those of welded plates from a view point of the inverse analysis. As a first step, a basic formulization was attempted to overcome this difficulty and future problems to be solved were made clear. Then computer simulations of the bead flush method conducted for a thin walled welded pipe confirmed its utility. Refs. 2 (author)

  10. Prediction method of seismic residual deformation of caisson quay wall in liquefied foundation

    Science.gov (United States)

    Wang, Li-Yan; Liu, Han-Long; Jiang, Peng-Ming; Chen, Xiang-Xiang

    2011-03-01

    The multi-spring shear mechanism plastic model in this paper is defined in strain space to simulate pore pressure generation and development in sands under cyclic loading and undrained conditions, and the rotation of principal stresses can also be simulated by the model with cyclic behavior of anisotropic consolidated sands. Seismic residual deformations of typical caisson quay walls under different engineering situations are analyzed in detail by the plastic model, and then an index of liquefaction extent is applied to describe the regularity of seismic residual deformation of caisson quay wall top under different engineering situations. Some correlated prediction formulas are derived from the results of regression analysis between seismic residual deformation of quay wall top and extent of liquefaction in the relative safety backfill sand site. Finally, the rationality and the reliability of the prediction methods are validated by test results of a 120 g-centrifuge shaking table, and the comparisons show that some reliable seismic residual deformation of caisson quay can be predicted by appropriate prediction formulas and appropriate index of liquefaction extent.

  11. Analysis of macro and micro residual stresses in functionally graded materials by diffraction methods

    CERN Document Server

    Dantz, D; Reimers, W

    1999-01-01

    The residual stress state in microwave sintered metal-ceramic functionally graded materials (FGM) consisting of 8Y-ZrO/sub 2//Ni and 8Y-ZrO/sub 2//NiCr8020, respectively, was analysed by non- destructive diffraction methods. In $9 order to get knowledge of the complete residual stress state in the near surface region as well as in the interior of the material, complementary methods were applied. Whereas the surface was characterised by X-ray techniques using $9 conventional sources, the stresses within the bulk of the material were investigated by means of high energy synchrotron radiation. The stress state was found to obey the differences in the coefficients of thermal expansion $9 (micro-stresses) on the one hand and the inhomogeneous cooling conditions (macrostresses) on the other hand. (7 refs).

  12. The MESERAN Method: Rapid Quantification of Non-Volatile Organic Residue (NVOR)

    Energy Technology Data Exchange (ETDEWEB)

    Benkovich, M.G.

    2002-06-13

    The precision analytical technique known as MESERAN Analysis permits quantitative measurement of the level of preexisting nonvolatile organic residue (NVOR) on a substrate from <1 nanogram (ng)/cm{sup 2} to > 100 micrograms ({micro}g)/cm{sup 2} in 2 minutes. MESERAN Analysis is also applicable to determining NVOR in solvents and solvent extracts. The MESERAN method is able to quantify organic contamination levels down to and below 1 ng by depositing as little as 10 microliters ({micro}L) of solvent containing a known amount of contamination on a clean substrate, allowing it to evaporate, and measuring the evaporated residue. The method will be described in detail and NVOR measurements determined from MESERAN data will be presented.

  13. Methods to Reduce Forest Residue Volume after Timber Harvesting and Produce Black Carbon

    Directory of Open Access Journals (Sweden)

    Deborah S. Page-Dumroese

    2017-01-01

    Full Text Available Forest restoration often includes thinning to reduce tree density and improve ecosystem processes and function while also reducing the risk of wildfire or insect and disease outbreaks. However, one drawback of these restoration treatments is that slash is often burned in piles that may damage the soil and require further restoration activities. Pile burning is currently used on many forest sites as the preferred method for residue disposal because piles can be burned at various times of the year and are usually more controlled than broadcast burns. In many cases, fire can be beneficial to site conditions and soil properties, but slash piles, with a large concentration of wood, needles, forest floor, and sometimes mineral soil, can cause long-term damage. We describe several alternative methods for reducing nonmerchantable forest residues that will help remove excess woody biomass, minimize detrimental soil impacts, and create charcoal for improving soil organic matter and carbon sequestration.

  14. Shifted Legendre method with residual error estimation for delay linear Fredholm integro-differential equations

    Directory of Open Access Journals (Sweden)

    Şuayip Yüzbaşı

    2017-03-01

    Full Text Available In this paper, we suggest a matrix method for obtaining the approximate solutions of the delay linear Fredholm integro-differential equations with constant coefficients using the shifted Legendre polynomials. The problem is considered with mixed conditions. Using the required matrix operations, the delay linear Fredholm integro-differential equation is transformed into a matrix equation. Additionally, error analysis for the method is presented using the residual function. Illustrative examples are given to demonstrate the efficiency of the method. The results obtained in this study are compared with the known results.

  15. RANDOM FUNCTIONS AND INTERVAL METHOD FOR PREDICTING THE RESIDUAL RESOURCE OF BUILDING STRUCTURES

    Directory of Open Access Journals (Sweden)

    Shmelev Gennadiy Dmitrievich

    2017-11-01

    Full Text Available Subject: possibility of using random functions and interval prediction method for estimating the residual life of building structures in the currently used buildings. Research objectives: coordination of ranges of values to develop predictions and random functions that characterize the processes being predicted. Materials and methods: when performing this research, the method of random functions and the method of interval prediction were used. Results: in the course of this work, the basic properties of random functions, including the properties of families of random functions, are studied. The coordination of time-varying impacts and loads on building structures is considered from the viewpoint of their influence on structures and representation of the structures’ behavior in the form of random functions. Several models of random functions are proposed for predicting individual parameters of structures. For each of the proposed models, its scope of application is defined. The article notes that the considered approach of forecasting has been used many times at various sites. In addition, the available results allowed the authors to develop a methodology for assessing the technical condition and residual life of building structures for the currently used facilities. Conclusions: we studied the possibility of using random functions and processes for the purposes of forecasting the residual service lives of structures in buildings and engineering constructions. We considered the possibility of using an interval forecasting approach to estimate changes in defining parameters of building structures and their technical condition. A comprehensive technique for forecasting the residual life of building structures using the interval approach is proposed.

  16. Analysis Method for Pesticides Residues by GC/MS in Lebanese Apple

    International Nuclear Information System (INIS)

    Jaber, F.; Al Iskandarani, M.

    2008-01-01

    The apple's crop can be affected by many pests during the growing season, which requires careful monitoring. Both apple fruit and apple tree need to be treated by pesticides in order to protect them from pests. Such treatment often leads to the accumulation of stable pesticides inside the fruit. The local market provides a large variety of pesticides allowing farmers to use more than one active substance in order to protect their crop, often without proper advice. Monitoring pesticides on apples and other agricultural crops is the best way to protect consumers health from the hazards of pesticides residues. The development of new, rapid and effective method to analyze the multi pesticides residues at trace levels in apple samples is essential. This work describes the extraction procedure and the analytical method developed to detect the pesticide residues using the gas-chromatographic-mass spectrometric approach (GC-MS). The developed method was successfully applied to analyze apple samples collected from different Lebanese markets for a one year period in order to monitor the presence of pesticides and their stability in apple fruits during storage. (author)

  17. Validation of methods used in the Florida Department of Agricultural and Consumer Services' Chemical Residue Laboratory.

    Science.gov (United States)

    Parker, G A

    1991-01-01

    Very few methods for detecting residues of pesticides in food or agricultural samples have undergone rigorous colloborative study and possess official AOAC status. The Chemical Residue Laboratory has formalized a method validation scheme to use when incorporating or developing new, unofficial methods. These methods are validated by assessing certain performance parameters: scope, specificity, linear range, accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ). For accuracy and precision assessment, 12 replicate fortifications must yield recoveries within the range of 70-120% with a coefficient of variation (CV) that compares favorably to the Horwitz CV. LOD and LOQ are equivalent to 3 and 10 times, respectively, the background signal contributed by a sample matrix blank. This criterion that we use for LOD/LOQ is not universal. In fact, because of differing definitions, we have encountered difficulties in enforcing a tolerance by using a registrant's method. This paper also presents an example of our method validation scheme, using a recent method development project for detecting sulfamethazine in raw milk. The sulfamethazine project also revealed unanticipated personnel problems, underscoring the importance of the human factor in quality assurance.

  18. [Comparison of pretreatment methods for the simultaneous determination of diclazuril and toltrazuril residues in chicken tissues].

    Science.gov (United States)

    Shi, Zuhao; Ge, Qinglian; Lu, Junxian; Liu, Xuexian; Gong, Jiansen; Zhu, Liangqiang; Qi, Kezong; Chen, Dingding; Peng, Kaisong

    2009-05-01

    The effects of four pretreatment methods (acetonitrile extraction-evaporation concentration, acetonitrile extraction-solid phase extraction (SPE), matrix solid-phase dispersion (MSPD) extraction and MSPD-SPE) for the simultaneous analysis of diclazuril and toltrazuril residues in chicken tissues were compared. The average recovery of 70% for the former three methods as achieved. In comparison with other methods, the MSPD method saved more than 60% in time and solvent. So, MSPD as the sample pretreatment method, an MSPD-high performance liquid chromatography with ultraviolet detection (MSPD-HPLC/UV) method was established for the analysis. Under the optimal chromatographic conditions, the linear range was between 50 and 1,000 microg/kg. At the added levels of 50, 500, 1,000 ng/g, the recoveries of diclazuril and toltrazuril in chicken tissues ranged from 71.13% - 84.02% with the relative standard deviations (RSD) in the range of 3.76% - 12.11%, and the RSDs of intra- and interday analyses ranged from 3.70% - 6.77%. The detection limits of diclazuril and toltrazuril were less than 10 microg/kg. The quantitative limits of diclazuril and toltrazuril were less than 20 microg/kg. The method meet the requirements of the residue analysis on accuracy and precision.

  19. Application of Scharer's quantitative method for the determination of residual alkaline phosphatase activity in standard Minas

    Directory of Open Access Journals (Sweden)

    C.F. Soares

    2013-08-01

    Full Text Available Milk pasteurization is a critical issue in the dairy industry, and failures in this process can affect final product safety. Scharer's enzymatic method is still traditionally used to verify pasteurization efficiency compliance, and it is based on screening for residual alkaline phosphatase in milk. Although several methods are used to quantify enzymatic activity to assess milk pasteurization efficiency, there is a small amount of published data regarding the use of these methods to quantify alkaline phosphatase in cheese. In this study, the Scharer's modified method was used to determine the levels of residual alkaline phosphatase in standard minas cheese, before and after 20 days of ripening. The cheeses were made using raw or pasteurized milk with the addition of different concentrations of raw milk (0; 0.05%; 0.10%; 0.20%; and 0.50%. In the fresh cheese samples, the method showed a sensitivity of only 0.50% with the addition of raw milk to the pasteurized milk used to make cheese. In addition, levels of up 0.20% of raw milk in pasteurized milk, the concentrations of phenol was inferior to 1μg phenol/g of dairy product which is the preconized indicator value for adequate pasteurization.

  20. Quantitative determination of pefloxacin mesylate by residual-base neutralisation method

    Directory of Open Access Journals (Sweden)

    HULIKALCHANDRA SHEKAR PRAMEELA

    2004-05-01

    Full Text Available This work describes two procedures based on residual base determination for the quantification of pefloxacin mesylate (PFM in bulk drug and in pharmaceutical products. In the first method involving titrimetry, the drug solution is treated with a measured excess of sodium hydroxide followed by back titration of the residual base with hydrochloric acid using a phenol red-bromothymol blue mixed indicator. The second spectrophotometrie method involves treatment of a fixed amount of sodium hydroxide – phenol red mixture with varying amounts of the drug, and measuring the decrease in the absorbance of the dye at 560 nm. In the titrimetric method, a reaction stoichiometry of 1:1 was found in the quantification range of 4–20 mg of drug. The spectrophotometric method allows the determination of PFM in the 5–40 mg ml-1 range. The molar absorptivity is 5.91¤103 l mol-1 cm-1 and the Sandell sensitivity is 56.37 ng cm-2. The methods were applied successfully to the determination of PFM in pharmaceutical preparations.

  1. Microbial screening for quinolones residues in cow milk by bio-optical method.

    Science.gov (United States)

    Appicciafuoco, Brunella; Dragone, Roberto; Frazzoli, Chiara; Bolzoni, Giuseppe; Mantovani, Alberto; Ferrini, Anna Maria

    2015-03-15

    The use of antibiotics on lactating cows should be monitored for the possible risk of milk contamination with residues. Accordingly, Maximum Residue Levels (MRLs) are established by the European Commission to guarantee consumers safety. As pointed out by Dec 2002/657/EC, screening is the first step in the strategy for antibiotic residue control, thus playing a key role in the whole control procedure. However, current routine screening methods applied in milk chain still fail to detect residues of quinolones at concentrations of interest. This paper reports the findings of a new bio-optical method for the screening of quinolones residues in bovine milk, based on E. coli ATCC 11303 growth inhibition. The effect of blank and spiked cow milk samples (aliquots equivalents to 0.8%, v/v) is evaluated in Mueller Hinton Broth (MHb) and MHb enriched with MgSO4 2% (MHb-Mg) inoculated with the test strain at the concentration of 10(4)CFU/mL. The presence of quinolones inhibits the cellular growth in MHb, while this effect is neutralized in MHb-Mg allowing both detection and presumptive identification of quinolones. Growth of the test strain is monitored at 37 °C in a Bioscreen C automated system, and Optical Density (OD) at 600 nm is recorded every 10 min after shaking for 10s. Growth curves (OD vs. time) of E. coli ATCC 11303 are assessed in milk samples, with and without quinolones, and their differences in terms of ΔOD (ΔOD600nm=ODMHb-Mg-ODMHb) are calculated. The presence of quinolones is detected by the cellular growth inhibition (OD vs time, none increase in the value OD) and presumptively identified through the increase of the slope of ΔOD600nm curve (ΔOD vs. time), after about 3h of incubation. The detection limit for ciprofloxacin and enrofloxacin is at the level of MRL, for marbofloxacin is at 2-fold the MRL whereas for danofloxacin is at 4-fold the MRL. Although the sensitivity of the method could be further improved and the procedure automated, it is a

  2. Modification and re-validation of the ethyl acetate-based multi-residue method for pesticides in produce

    NARCIS (Netherlands)

    Mol, J.G.J.; Rooseboom, A.; Dam, van R.; Roding, M.; Arondeus, K.; Sunarto, S.

    2007-01-01

    The ethyl acetate-based multi-residue method for determination of pesticide residues in produce has been modified for gas chromatographic (GC) analysis by implementation of dispersive solid-phase extraction (using primary¿secondary amine and graphitized carbon black) and large-volume (20 ¿L)

  3. Modification and re-validation of the ethyl acetate-based multi-residue method for pesticides in produce

    NARCIS (Netherlands)

    Mol, H.G.J.; Rooseboom, A.; Dam, R. van; Roding, M.; Arondeus, K.; Sunarto, S.

    2007-01-01

    The ethyl acetate-based multi-residue method for determination of pesticide residues in produce has been modified for gas chromatographic (GC) analysis by implementation of dispersive solid-phase extraction (using primary-secondary amine and graphitized carbon black) and large-volume (20 μL)

  4. A method for assessing residual NAPL based on organic chemical concentrations in soil samples

    International Nuclear Information System (INIS)

    Feenstra, S.; Mackay, D.M.; Cherry, J.A.

    1991-01-01

    Ground water contamination by non-aqueous phase liquid (NAPL) chemicals is a serious concern at many industrial facilities and waste disposal sites. NAPL in the form of immobile residual contamination, or pools of mobile or potentially mobile NAPL, can represent continuing sources of ground water contamination. In order to develop rational and cost-effective plans for remediation of soil and ground water contamination at such sites, it is essential to determine if non-aqueous phase liquid (NAPL) chemicals are present in the subsurface and delineate the zones of NAPL contamination. Qualitatively, soil analyses that exhibit chemical concentrations in the percent range or >10,000 mg/kg would generally be considered to indicate the presence of NAPL. However, the results of soil analyses are seldom used in a quantitative manner to assess the possible presence of residual NAPL contamination when chemical concentrations are lower and the presence of NAPL is not obvious. The assessment of the presence of NAPL in soil samples is possible using the results of chemical and physical analyses of the soil, and the fundamental principles of chemical partitioning in unsaturated or saturated soil. The method requires information on the soil of the type typically considered in ground water contamination studies and provides a simple tool for the investigators of chemical spill and waste disposal sites to assess whether soil chemical analyses indicate the presence of residual NAPL in the subsurface

  5. Use of a dynamic grid adaptation in the asymmetric weighted residual method

    International Nuclear Information System (INIS)

    Graf, V.; Romstedt, P.; Werner, W.

    1986-01-01

    A dynamic grid adaptive method has been developed for use with the asymmetric weighted residual method. The method automatically adapts the number and position of the spatial mesh points as the solution of hyperbolic or parabolic vector partial differential equations progresses in time. The mesh selection algorithm is based on the minimization of the L 2 norm of the spatial discretization error. The method permits the accurate calculation of the evolution of inhomogeneities, like wave fronts, shock layers, and other sharp transitions, while generally using a coarse computational grid. The number of required mesh points is significantly reduced, relative to a fixed Eulerian grid. Since the mesh selection algorithm is computationally inexpensive, a corresponding reduction of computing time results

  6. Comparison between some determination methods of residual styrene in plastic scintillators

    International Nuclear Information System (INIS)

    Bezuglyi, V.D.; Ponomarev, Yu.P.; Gunder, O.A.; Biteman, V.B.; Senchishin, V.G.

    1988-01-01

    Scintillators made of plastic materials based on polystyrene with addition of p-terphenyl and 1,4-di-[(2,5-phenyl)oxazolyl] benzene have found wide application principally in the detection of radioactivity. The stability of the scintillating characteristics of these materials depends to great degree on the concentration of the residual monomer and for this reason it is important to have a sufficiently convenient method for the determination of this latter. We investigated the bromometric and acid-base titration methods with visual and potentiometric titration end point detection. We also examined the polarographic methods, direct and indirect, using the electroreduction of the mercury acetate complex of the monomer. We checked the methods on a scintillator sample and on synthetic mixtures, i.e., mixtures of monomer, polymer, and p-terphenyl. We compared the determination results for styrene and showed that the most accurate procedure is the bromometric determination with potentiometric indication of the end-point

  7. Development of an on-site measurement method for residual stress in primary system piping of nuclear power plants

    International Nuclear Information System (INIS)

    Maekawa, Akira; Takahashi, Shigeru; Fujiwara, Masaharu

    2014-01-01

    In residual stress measurement for large-scale pipes and vessels in high radiation areas and highly contaminated areas of nuclear plants, it is difficult to bring the radioactivated pipes and vessels out of the areas as they are. If they can brought out, it is very burdensome to handle them for the measurement. Development of an on-site measurement method of residual stress which can be quickly applied and has sufficient measurement accuracy is desirable. In this study, a new method combining an electric discharge skim-cut method with a microscopic strain measurement method using markers was proposed to realize the on-site residual stress measurement on pipes in high radiation areas and highly contaminated areas. In the electric discharge skim-cut method, a boat-type sample is skimmed out of a pipe outer/inner surface using electric discharge machining and released residual stress is measured. The on-site measurement of residual stress by the method can be done using a small, portable electric discharge machine. In the microscopic strain measurement method using markers, the residual stress is estimated by microscopic measurement of the distance between markers after the stress release. The combination of both methods can evaluate the residual stress with the same accuracy as conventional methods offer and it can achieve reduction of radiation exposure in the measurement because the work is done simply and rapidly. In this study, the applicability of the electric discharge skim-cut method was investigated because the applicability of the microscopic strain measurement method using markers was confirmed previously. The experimental examination clarified the applicable conditions for the residual stress measurement with the same accuracy as the conventional methods. Furthermore, the electric discharge machining conditions using pure water as the machining liquid was found to eliminate the amount of liquid radioactive waste completely. (author)

  8. Evaluation of two fast and easy methods for pesticide residue analysis in fatty food matrixes.

    Science.gov (United States)

    Lehotay, Steven J; Mastovská, Katerina; Yun, Seon Jong

    2005-01-01

    Two rapid methods of sample preparation and analysis of fatty foods (e.g., milk, eggs, and avocado) were evaluated and compared for 32 pesticide residues representing a wide range of physicochemical properties. One method, dubbed the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for pesticide residue analysis, entailed extraction of 15 g sample with 15 mL acetonitrile (MeCN) containing 1% acetic acid followed by addition of 6 g anhydrous magnesium sulfate and 1.5 g sodium acetate. After centrifugation, 1 mL of the buffered MeCN extract underwent a cleanup step (in a technique known as dispersive solid-phase extraction) using 50 mg each of C18 and primary secondary amine sorbents plus 150 mg MgSO4. The second method incorporated a form of matrix solid-phase dispersion (MSPD), in which 0.5 g sample plus 2 g C18 and 2 g anhydrous sodium sulfate was mixed in a mortar and pestle and added above a 2 g Florisil column on a vacuum manifold. Then, 5 x 2 mL MeCN was used to elute the pesticide analytes from the sample into a collection tube, and the extract was concentrated to 0.5 mL by evaporation. Extracts in both methods were analyzed concurrently by gas chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry. The recoveries of semi-polar and polar pesticides were typically 100% in both methods (except that basic pesticides, such as thiabendazole and imazalil, were not recovered in the MSPD method), but recovery of nonpolar pesticides decreased as fat content of the sample increased. This trend was more pronounced in the QuEChERS method, in which case the most lipophilic analyte tested, hexachlorobenzene, gave 27 +/- 1% recovery (n=6) in avocado (15% fat) with a<10 ng/g limit of quantitation.

  9. A new one-platform flow cytometric method for residual cell counting in platelet concentrates.

    Science.gov (United States)

    Schmidt, Michael; Spengler, Hans-Peter; Lambrecht, Bernd; Hourfar, Michael K; Seifried, Erhard; Tonn, Torsten

    2009-12-01

    According to German regulations and guidelines, residual red blood cells (rRBCs) and residual white blood cells (rWBCs) must number fewer than 3 x 10(9) cells/unit and 1 x 10(6) cells/unit in platelet concentrates (PCs), respectively. Due to low levels of residual cells in final products, there is still a need for fast, reliable, and sensitive methods of automated detection of these cell types. In Part A, 21 PCs were spiked with predetermined numbers of red blood cells (RBCs) and white blood cells (WBCs). The linearity, precision, and accuracy of the BD Thrombo Count assay (BD Biosciences Europe) were tested and validated according to international guidelines. Finally in Part B, 100 PCs prepared from pooled buffy coats were tested by the BD Thrombo Count assay and compared with other methods, including Nageotte (rWBCs) and Neubauer (rRBCs) counting chambers and the flow cytometric BD LeucoCOUNT (Becton Dickinson) assay (rWBCs). The unspecific background of blank PC samples was fewer than 0.02 cells/microL for WBCs and fewer than 34 cells/microL for RBCs (mean, 21). Linear regression and precision analyses of spiked PC samples were determined for both WBCs (r(2) = 0.992; range, 0.6-6.0 WBCs/microL) and RBCs (r(2) = 0.999; 800-8000 RBCs/microL). No carryover of cells or drift in results was detected in the automated sample acquisition mode. Analysis according to statistical methods of Bland and Altman demonstrated a high correlation between BD Thrombo Count and the Neubauer manual counting chamber. This novel flow cytometric test is a quick and reliable single-tube assay that has been demonstrated as a potential alternative for the existing manual microscopic counting procedures that are both time-consuming and laborious.

  10. Evaluation of residual antibacterial potency in antibiotic production wastewater using a real-time quantitative method.

    Science.gov (United States)

    Zhang, Hong; Zhang, Yu; Yang, Min; Liu, Miaomiao

    2015-11-01

    While antibiotic pollution has attracted considerable attention due to its potential in promoting the dissemination of antibiotic resistance genes in the environment, the antibiotic activity of their related substances has been neglected, which may underestimate the environmental impacts of antibiotic wastewater discharge. In this study, a real-time quantitative approach was established to evaluate the residual antibacterial potency of antibiotics and related substances in antibiotic production wastewater (APW) by comparing the growth of a standard bacterial strain (Staphylococcus aureus) in tested water samples with a standard reference substance (e.g. oxytetracycline). Antibiotic equivalent quantity (EQ) was used to express antibacterial potency, which made it possible to assess the contribution of each compound to the antibiotic activity in APW. The real-time quantitative method showed better repeatability (Relative Standard Deviation, RSD 1.08%) compared with the conventional fixed growth time method (RSD 5.62-11.29%). And its quantification limits ranged from 0.20 to 24.00 μg L(-1), depending on the antibiotic. We applied the developed method to analyze the residual potency of water samples from four APW treatment systems, and confirmed a significant contribution from antibiotic transformation products to potent antibacterial activity. Specifically, neospiramycin, a major transformation product of spiramycin, was found to contribute 13.15-22.89% of residual potency in spiramycin production wastewater. In addition, some unknown related substances with antimicrobial activity were indicated in the effluent. This developed approach will be effective for the management of antibacterial potency discharge from antibiotic wastewater and other waste streams.

  11. Residual-based a posteriori error estimation for multipoint flux mixed finite element methods

    KAUST Repository

    Du, Shaohong

    2015-10-26

    A novel residual-type a posteriori error analysis technique is developed for multipoint flux mixed finite element methods for flow in porous media in two or three space dimensions. The derived a posteriori error estimator for the velocity and pressure error in L-norm consists of discretization and quadrature indicators, and is shown to be reliable and efficient. The main tools of analysis are a locally postprocessed approximation to the pressure solution of an auxiliary problem and a quadrature error estimate. Numerical experiments are presented to illustrate the competitive behavior of the estimator.

  12. [Research on rapid and quantitative detection method for organophosphorus pesticide residue].

    Science.gov (United States)

    Sun, Yuan-Xin; Chen, Bing-Tai; Yi, Sen; Sun, Ming

    2014-05-01

    The methods of physical-chemical inspection is adopted in the traditional pesticide residue detection, which require a lot of pretreatment processes, are time-consuming and complicated. In the present study, the authors take chlorpyrifos applied widely in the present agricultural field as the research object and propose a rapid and quantitative detection method for organophosphorus pesticide residues. At first, according to the chemical characteristics of chlorpyrifos and comprehensive chromogenic effect of several colorimetric reagents and secondary pollution, the pretreatment of the scheme of chromogenic reaction of chlorpyrifos with resorcin in a weak alkaline environment was determined. Secondly, by analyzing Uv-Vis spectrum data of chlorpyrifos samples whose content were between 0. 5 and 400 mg kg-1, it was confirmed that the characteristic information after the color reaction mainly was concentrated among 360 approximately 400 nm. Thirdly, the full spectrum forecasting model was established based on the partial least squares, whose correlation coefficient of calibration was 0. 999 6, correlation coefficient of prediction reached 0. 995 6, standard deviation of calibration (RMSEC) was 2. 814 7 mg kg-1, and standard deviation of verification (RMSEP) was 8. 012 4 mg kg-1. Fourthly, the wavelengths whose center wavelength is 400 nm was extracted as characteristic region to build a forecasting model, whose correlation coefficient of calibration was 0. 999 6, correlation coefficient of prediction reached 0. 999 3, standard deviation of calibration (RMSEC) was 2. 566 7 mg kg-1 , standard deviation of verification (RMSEP) was 4. 886 6 mg kg-1, respectively. At last, by analyzing the near infrared spectrum data of chlorpyrifos samples with contents between 0. 5 and 16 mg kg-1, the authors found that although the characteristics of the chromogenic functional group are not obvious, the change of absorption peaks of resorcin itself in the neighborhood of 5 200 cm

  13. Generation and importance of linked and irreducible moment diagrams in the recursive residue generation method

    International Nuclear Information System (INIS)

    Schek, I.; Wyatt, R.E.

    1986-01-01

    Molecular multiphoton processes are treated in the Recursive Residue Generation Method (A. Nauts and R.E. Wyatt, Phys. Rev. Lett 51, 2238 (1983)) by converting the molecular-field Hamiltonian matrix into tridiagonal form, using the Lanczos equations. In this study, the self-energies (diagonal) and linking (off-diagaonal) terms in the tridiagonal matrix are obtained by comparing linked moment diagrams in both representations. The dynamics of the source state is introduced and computed in terms of the linked and the irreducible moments

  14. Validation of quantitative method for azoxystrobin residues in green beans and peas.

    Science.gov (United States)

    Abdelraheem, Ehab M H; Hassan, Sayed M; Arief, Mohamed M H; Mohammad, Somaia G

    2015-09-01

    This study presents a method validation for extraction and quantitative analysis of azoxystrobin residues in green beans and peas using HPLC-UV and the results confirmed by GC-MS. The employed method involved initial extraction with acetonitrile after the addition of salts (magnesium sulfate and sodium chloride), followed by a cleanup step by activated neutral carbon. Validation parameters; linearity, matrix effect, LOQ, specificity, trueness and repeatability precision were attained. The spiking levels for the trueness and the precision experiments were (0.1, 0.5, 3 mg/kg). For HPLC-UV analysis, mean recoveries ranged between 83.69% to 91.58% and 81.99% to 107.85% for green beans and peas, respectively. For GC-MS analysis, mean recoveries ranged from 76.29% to 94.56% and 80.77% to 100.91% for green beans and peas, respectively. According to these results, the method has been proven to be efficient for extraction and determination of azoxystrobin residues in green beans and peas. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Measuring multiple residual-stress components using the contour method and multiple cuts

    Energy Technology Data Exchange (ETDEWEB)

    Prime, Michael B [Los Alamos National Laboratory; Swenson, Hunter [Los Alamos National Laboratory; Pagliaro, Pierluigi [U. PALERMO; Zuccarello, Bernardo [U. PALERMO

    2009-01-01

    The conventional contour method determines one component of stress over the cross section of a part. The part is cut into two, the contour of the exposed surface is measured, and Bueckner's superposition principle is analytically applied to calculate stresses. In this paper, the contour method is extended to the measurement of multiple stress components by making multiple cuts with subsequent applications of superposition. The theory and limitations are described. The theory is experimentally tested on a 316L stainless steel disk with residual stresses induced by plastically indenting the central portion of the disk. The stress results are validated against independent measurements using neutron diffraction. The theory has implications beyond just multiple cuts. The contour method measurements and calculations for the first cut reveal how the residual stresses have changed throughout the part. Subsequent measurements of partially relaxed stresses by other techniques, such as laboratory x-rays, hole drilling, or neutron or synchrotron diffraction, can be superimposed back to the original state of the body.

  16. Comparative analysis of different methods of extraction of present hydrocarbons in industrial residual waters

    International Nuclear Information System (INIS)

    Santa, Judith Rocio; Serrano, Martin; Stashenko, Elena

    2002-01-01

    A comparison among four extraction techniques such as: liquid - liquid (LLE) continuous and for lots, solid phase extraction (SPE), solid phase micro extraction (SPME) and static headspace (S-HS) was carried out. The main purpose of this research was to determine the highest recovery efficiencies and how reproducible the tests are while varying parameters such as time, extraction technique, type of solvents and others. Chromatographic parameters were optimized in order to carry out the analyses. Hydrocarbon's quantification of residual waters was achieved by using a high-resolution gas chromatography with a gas flame ionization detector (HRGC-FID). Validation of the method was carried out by analyzing real samples taken in different sampling places of the residual waters treatment plant of Ecopetrol - Barrancabermeja. The use of extraction methods that require big solvent quantities and long time for analysis are losing validity day by day. Techniques such as the HS-SPME and static HS are offered as alternatives for quantifying hydrocarbons. They show total lack of solvents, high sensibility, selectivity and the techniques are reproducible. Solid phase micro extraction (SPME) and static headspace (static HS) techniques were chosen as the extraction techniques to validate the method in real samples. Both techniques showed similar results for the determination of total hydrocarbons (in the gasoline range)

  17. Effect of the sequence data deluge on the performance of methods for detecting protein functional residues.

    Science.gov (United States)

    Garrido-Martín, Diego; Pazos, Florencio

    2018-02-27

    The exponential accumulation of new sequences in public databases is expected to improve the performance of all the approaches for predicting protein structural and functional features. Nevertheless, this was never assessed or quantified for some widely used methodologies, such as those aimed at detecting functional sites and functional subfamilies in protein multiple sequence alignments. Using raw protein sequences as only input, these approaches can detect fully conserved positions, as well as those with a family-dependent conservation pattern. Both types of residues are routinely used as predictors of functional sites and, consequently, understanding how the sequence content of the databases affects them is relevant and timely. In this work we evaluate how the growth and change with time in the content of sequence databases affect five sequence-based approaches for detecting functional sites and subfamilies. We do that by recreating historical versions of the multiple sequence alignments that would have been obtained in the past based on the database contents at different time points, covering a period of 20 years. Applying the methods to these historical alignments allows quantifying the temporal variation in their performance. Our results show that the number of families to which these methods can be applied sharply increases with time, while their ability to detect potentially functional residues remains almost constant. These results are informative for the methods' developers and final users, and may have implications in the design of new sequencing initiatives.

  18. Assessment of Protein Side-Chain Conformation Prediction Methods in Different Residue Environments

    Science.gov (United States)

    Peterson, Lenna X.; Kang, Xuejiao; Kihara, Daisuke

    2016-01-01

    Computational prediction of side-chain conformation is an important component of protein structure prediction. Accurate side-chain prediction is crucial for practical applications of protein structure models that need atomic detailed resolution such as protein and ligand design. We evaluated the accuracy of eight side-chain prediction methods in reproducing the side-chain conformations of experimentally solved structures deposited to the Protein Data Bank. Prediction accuracy was evaluated for a total of four different structural environments (buried, surface, interface, and membrane-spanning) in three different protein types (monomeric, multimeric, and membrane). Overall, the highest accuracy was observed for buried residues in monomeric and multimeric proteins. Notably, side-chains at protein interfaces and membrane-spanning regions were better predicted than surface residues even though the methods did not all use multimeric and membrane proteins for training. Thus, we conclude that the current methods are as practically useful for modeling protein docking interfaces and membrane-spanning regions as for modeling monomers. PMID:24619909

  19. Residual stress measurement of EB-welded plates with contour method. Part 2: FEM analysis of contour profiles

    International Nuclear Information System (INIS)

    Romppanen, A.-J.; Immonen, E.

    2013-12-01

    The residual stresses formed as a result of Electronic Beam welding (EB-welding) in copper are investigated by Posiva. In the present study, residual stresses of EB-welded copper plates were studied with contour method. In the method eleven copper plates (X436 - X440 and X453 - X458) were cut in half with wire electric discharge machining (EDM) after which the deformation due to stress relaxation was measured with coordinate measurement system. The measured data was then used as boundary displacement data for the FEM analyses, in which the corresponding residual stresses were calculated. Before giving the corresponding displacement boundary conditions to the FE models, the deformation data was processed and smoothed appropriately. The residual stress levels of the copper plates were found to be around 40 - 55 MPa at maximum. This corresponds to other reported residual stress measurements and current state of knowledge with this material in Posiva. (orig.)

  20. Treatment methods and comparative risks of thorium removal from waste residues

    Energy Technology Data Exchange (ETDEWEB)

    Porter, R.D.; Hamby, D.M.; Martin, J.E.

    1997-07-01

    This study was done to examine the risks of remediation and the effectiveness of removal methods for thorium and its associated radioactive decay products from various soils and wastes associated with DOE`s Formerly Utilized Sites Remedial Action Program (FUSRAP). Removal of {sup 230}Th from uranium process residues would significantly reduce the buildup of {sup 226}Ra (half-life of 1600 years), and since {sup 230}Th concentrations at most of the important sites greatly exceed the {sup 226}Ra concentrations, such removal would reduce the accumulation of additional radiation risks associated with {sup 226}Ra and its products; and, if treatment also removed {sup 226}Ra, these risks could be mitigated even further. Removal of {sup 232}Th from thorium process residues would remove the source material for {sup 228}Ra, and since {sup 228}Ra has a half-life of 5.76 years, its control at FUSRAP sites could be done with land use controls for the 30--50 years required for {sup 228}Ra and the risks associated with its decay products to decay away. It must be recognized, however, that treatment methods invariably require workers to process residues and waste materials usually with bulk handling techniques. These processes expose workers to the radioactivity in the materials, therefore, workers would incur radiological risks in addition to industrial accident risks. An important question is whether the potential reduction of future radiological risks to members of the public justifies the risks that are incurred by remediation workers due to handling materials. This study examines, first, the effectiveness of treatment and then the risks that would be associated with remediation.

  1. Zeranol: a review of the metabolism, toxicology, and analytical methods for detection of tissue residues

    International Nuclear Information System (INIS)

    Baldwin, R.S.; Williams, R.D.; Terry, M.K.

    1983-01-01

    Zeranol, an anabolic agent produced commercially for use in cattle and sheep intended for human consumption, is noncarcinogenic, nonteratogenic, and nonmutagenic. Toxicity testing (acute, subacute, and chronic) in several species by various routes of administration reveals an extremely low toxicity, the oral rat LD 50 exceeding 40 g/kg. Postmortem abnormalities of high-dose animals are attributed to the effects of the compound on the endocrine system. Both zeranol itself and zearalanone, the major Phase I metabolite in the seven species studied, are excreted in the feces and in the urine, either free or as sulfates/glucuronides. A minor urinary metabolite has been identified as taleranol, an epimer of zeranol. Both metabolites exhibit a very low order of toxicity (oral rat LD 50 exceeding 10 g/kg in both cases), and both exhibit less biological activity than the parent compound. The four types of analytical methods which have been employed for the specific detection and quantitation of residues of zeranol in edible tissues are: (1) gas chromatography (detection limit . 20 ppb), (2) high-performance liquid chromatography (detection limit . 5 ppb), (3) thin-layer chromatography (detection limit . 1-3 ppb), and (4) radioimmunoassay methods (detection limit to be published). The following residue levels were determined radiometrically in tissue samples taken 45 days after implantation of cattle with 36 mg tritiated zeranol: less than or equal to 2 ppb in liver, less than or equal to 1 ppb in kidney and fat, and less than or equal to 0.2 ppb in muscle and plasma. A no-effect level (NEL) of 0.225 mg/kg was determined as the highest oral dosage of zeranol which produced no estrogenic effects in female monkeys. Based on the NEL, a tolerance level for tissue residues of zeranol was calculated as 315 ppb

  2. Treatment methods and comparative risks of thorium removal from waste residues

    International Nuclear Information System (INIS)

    Porter, R.D.; Hamby, D.M.; Martin, J.E.

    1997-07-01

    This study was done to examine the risks of remediation and the effectiveness of removal methods for thorium and its associated radioactive decay products from various soils and wastes associated with DOE's Formerly Utilized Sites Remedial Action Program (FUSRAP). Removal of 230 Th from uranium process residues would significantly reduce the buildup of 226 Ra (half-life of 1600 years), and since 230 Th concentrations at most of the important sites greatly exceed the 226 Ra concentrations, such removal would reduce the accumulation of additional radiation risks associated with 226 Ra and its products; and, if treatment also removed 226 Ra, these risks could be mitigated even further. Removal of 232 Th from thorium process residues would remove the source material for 228 Ra, and since 228 Ra has a half-life of 5.76 years, its control at FUSRAP sites could be done with land use controls for the 30--50 years required for 228 Ra and the risks associated with its decay products to decay away. It must be recognized, however, that treatment methods invariably require workers to process residues and waste materials usually with bulk handling techniques. These processes expose workers to the radioactivity in the materials, therefore, workers would incur radiological risks in addition to industrial accident risks. An important question is whether the potential reduction of future radiological risks to members of the public justifies the risks that are incurred by remediation workers due to handling materials. This study examines, first, the effectiveness of treatment and then the risks that would be associated with remediation

  3. Marker-based method to measure movement between the residual limb and a transtibial prosthetic socket.

    Science.gov (United States)

    Childers, Walter Lee; Siebert, Steven

    2016-12-01

    Limb movement between the residuum and socket continues to be an underlying factor in limb health, prosthetic comfort, and gait performance yet techniques to measure this have been underdeveloped. Develop a method to measure motion between the residual limb and a transtibial prosthetic socket. Single subject, repeated measures with mathematical modeling. The gait of a participant with transtibial amputation was recorded using a motion capture system using a marker set that included arrays on the anterior distal tibia and the lateral epicondyle of the femur. The proximal or distal translation, anterior or posterior translation, and angular movements were quantified. A random Monte Carlo simulation based on the precision of the motion capture system and a model of the bone moving under the skin explored the technique's accuracy. Residual limb tissue stiffness was modeled as a linear spring based on data from Papaioannou et al. Residuum movement relative to the socket went through ~30 mm, 18 mm, and 15° range of motion. Root mean squared errors were 5.47 mm, 1.86 mm, and 0.75° when considering the modeled bone-skin movement in the proximal or distal, anterior or posterior, and angular directions, respectively. The measured movement was greater than the root mean squared error, indicating that this method can measure motion between the residuum and socket. The ability to quantify movement between the residual limb and the prosthetic socket will improve prosthetic treatment through the evaluation of different prosthetic suspensions, socket designs, and motor control of the prosthetic interface. © The International Society for Prosthetics and Orthotics 2015.

  4. Method for the Collection, Gravimetric and Chemical Analysis of Nonvolatile Residue (NVR) on Surfaces

    Science.gov (United States)

    Gordon, Keith; Rutherford, Gugu; Aranda, Denisse

    2017-01-01

    Nonvolatile residue (NVR), sometimes referred to as molecular contamination is the term used for the total composition of the inorganic and high boiling point organic components in particulates and molecular films deposited on critical surfaces surrounding space structures, with the particulate and NVR contamination originating primarily from pre-launch operations. The "nonvolatile" suggestion from the terminology NVR implies that the collected residue will not experience much loss under ambient conditions. NVR has been shown to have a dramatic impact on the ability to perform optical measurements from platforms based in space. Such contaminants can be detected early by the controlled application of various detection techniques and contamination analyses. Contamination analyses are the techniques used to determine if materials, components, and subsystems can be expected to meet the performance requirements of a system. Of particular concern is the quantity of NVR contaminants that might be deposited on critical payload surfaces from these sources. Subsequent chemical analysis of the contaminant samples by infrared spectroscopy and gas chromatography mass spectrometry identifies the components, gives semi-quantitative estimates of contaminant thickness, indicates possible sources of the NVR, and provides guidance for effective cleanup procedures. In this report, a method for the collection and determination of the mass of NVR was generated by the authors at NASA Langley Research Center. This report describes the method developed and implemented for collecting NVR contaminants, and procedures for gravimetric and chemical analysis of the residue obtained. The result of this NVR analysis collaboration will help pave the way for Langley's ability to certify flight hardware outgassing requirements in support of flight projects such as Stratospheric Aerosol and Gas Experiment III (SAGE III), Clouds and the Earth's Radiant Energy System (CERES), Materials International

  5. Evaluating the residual stress in PbTiO3 thin films prepared by a polymeric chemical method

    International Nuclear Information System (INIS)

    Valim, D; Filho, A G Souza; Freire, P T C; Filho, J Mendes; Guarany, C A; Reis, R N; Araujo, E B

    2004-01-01

    We report a study of residual stress in PbTiO 3 (PT) thin films prepared on Si substrates by a polymeric chemical method. The E(1TO) frequency was used to evaluate the residual stress through an empirical equation available for bulk PT. We find that the residual stress in PT films increases as the film thickness decreases and conclude that it originates essentially from the contributions of extrinsic and intrinsic factors. Polarized Raman experiments showed that the PT films prepared by a polymeric chemical method are somewhat a-domain (polar axis c parallel to the substrate) oriented

  6. A method to determine residue levels of persistent organochlorine pesticides in human milk from Indonesian women.

    Science.gov (United States)

    Burke, Emma R; Holden, Alexis J; Shaw, Ian C

    2003-01-01

    A method has been developed for the analysis of organochlorine pesticides in human milk using solvent extraction, Florisil solid phase extraction clean-up and analysis by gas chromatography with an electron capture detector. The recovery of analytes from spiked milk samples was in the range 53 +/- 1% to 109 +/- 7% (n = 9). A small number of samples were obtained from women in a rural and an urban area of Indonesia and analysed using the developed method. The results are reported on a milk fat basis. All samples contained detectable residues of p,p'-DDT (urban mean 0.11 +/- 0.18 mgkg(-1) (n = 5), rural mean 0.07 +/- 0.03 mg kg(-1) (n = 5)) and p,p'-DDE (urban mean 0.05 +/- 0.04 m kg(-1) (n = 5), rural mean 0.76 +/- 1.46 mg kg(-1) (n = 5)). Residues of HCB, betaHCH, alpha-endosulfan and dieldrin were also detected in some samples. There was no significant difference (at the 95% confidence level) in levels of pesticides between urban and rural areas. The levels of organochlorine pesticides in milk from Indonesian women were lower than those reported from Indonesian women exposed to DDT through malaria eradication schemes and were similar to levels reported from UK and Japan.

  7. Pink shrimp (P. brasiliensis and P. paulensis) residue: influence of extraction method on carotenoid concentration.

    Science.gov (United States)

    Mezzomo, Natália; Maestri, Bianca; dos Santos, Renata Lazzaris; Maraschin, Marcelo; Ferreira, Sandra R S

    2011-09-15

    The main residue from the shrimp processing is formed by head and carapace and represents from 40 to 50% (w/w) of the integral shrimp. The recovery of the carotenoid fraction from this residue stands for an alternative to increase its aggregated value. Therefore, the objective of this study was to use the pink shrimp waste as raw material to obtain carotenoid enriched extracts, evaluating different pre-treatments and extraction methods. The shrimp waste was supplied by a local public market (Florianópolis, SC, Brazil). The investigation of the different pre-treatments applied to the raw material shows that cooking associated with milling and drying produced the extract richest in carotenoid fraction. The extraction methods considered in this work were Soxhlet, maceration and ultrasound by means of different organic solvents and also a vegetable oil as solvent. The extracts were evaluated in terms of yield, carotenoid profile, total carotenoid content (TCC), UV-Visible scanning spectrophotometry and mid-Fourier transform infrared spectroscopy (FTIR). The results indicate that shrimp waste can provide carotenoid enriched extracts, particularly astaxanthin, in concentrations up to 252 μg(astaxanthin)g(extract)(-1). The most adequate solvents were acetone and hexane: isopropanol (50:50, v/v) used in the maceration procedure. The UV-Vis results revealed the presence of carotenoids and flavonoids in the extracts while the FTIR spectroscopy indicated the existence of fatty acids, proteins, and phenolics. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Determination the Amount of Illegal Furazolidone Residues in Broilers in Ahvaz Abattoir by HPLC Method

    Directory of Open Access Journals (Sweden)

    A Fazlara

    2014-06-01

    Full Text Available Background & aim: due to the risks to human health, particularly in terms of carcinogenicity, the application of Furazolidone in animals which their products are consumed by human population is strongly prohibited. The purpose of this study was to determine the amount of unauthorized furazolidone in broiler chickens slaughtered in Ahvaz by using HPLC. Methods: In the present cross-sectional study which was conducted within six months, 100 broiler carcasses were randomly collected from Ahvaz slaughterhouses. Then by using ice, the carcasses were transported to the laboratory in less than 24 hours inorder to illicit the amount of furazolidone drug by the HPLC method. After extraction and degrading processes, using Ethyl-acetate and related protocols for isolation of Furazolidone from muscles, and also calibrating HPLC system to obtain standard curves, the amount of 20 microliters of each sample was injected to the HPLC device and the amounts of Furazolidone were determined in the mixture of pectoral and femoral muscles. Finally the obtained results were statistically analysed by using one sample t-test in the SPSS software. Results: The mean Furazolidone concentration in the mixture of femoral and thorasic muscles was 28.15±2.37 mg/kg. Thirty-nine percent of the samples were positive for containing illegal Furazolidone residue. Conclusion: According to the results of the current study, more attention is seriously recommended by authorized responsibilities to prevent the antibiotic residues such as furazolidone in poultry meat.

  9. Comparison of Methods for Bifenthrin Residues Determination in Fermented Wheat Samples

    Directory of Open Access Journals (Sweden)

    Tijana Đorđević

    2012-01-01

    Full Text Available Efficiency of three different sample preparation methods for GC/MS determinationof bifenthrin residues in wheat (Triticum spelta samples fermented by Lactobacillusplantarum was tested. The first method was based on a methanol:acetone=1:1 extractionfolowed by a purification on columns containing mixture of aluminium oxide and activatedcharcoal slurry-packed and eluted with dichlormethane, the second was based onmethanol:acetone=1:1 extraction folowed by the purification on florisil column and elutionby ethil acetate:acetone=4:1, while the third tested method was based on a combinationof the first two mentioned methods, thus methanol:acetone=1:1 extraction and clean-upthrought columns filled with a mixture of aluminum oxide and activated charcoal slurrypackedand eluted with ethil acetate:acetone=4:1. The second method was the most effectivefor obtaining satisfactory recoveries for bifenthrin in a range of 79-83% for four fortificationlevels, with good reproducibility i.e. RSD% in a range of 2.2-7.4%. The chosen methodwas further optimized by assessing the optimum volume of elution solvent used duringthe clean-up procedures. The highest recovery of 82.1% was obtained after elution with25 ml of solvent. Overall, two-step extraction with 25 ml of methanol:acetone=1:1 solventmix for 30 min, followed by clean-up procedure through a glass column with florisil coupledwith elution with 25 ml of ethyl acetate: acetone=4:1, allows simple, efficient and reliableGC/MS detection of bifenthrin residues from wheat grain fermented by L. plantarum.

  10. Application of a radiometric enzymic method for monitoring organophosphorus and carbamate insecticide residues in water of the Danube River

    International Nuclear Information System (INIS)

    Horvath, L.; Volford, J.; Bursics, L.; Forster, T.

    1983-01-01

    Pesticide residue analyses are conventionally based on gas chromatography. These analytic procedures include tedious extraction and clear-up manipulations prior to the actual gas chromatographic determinations. Radioenzymatic method was recently applied in a residue monitoring programme on the Danube River. The programme has demonstrated that the radioenzymatic method has many advantages as a monitoring procedure in aquatic environment. Quick information can be gained without tedious sample clear-up procedure. The anticholinesteratic pesticides and the anticholinesteratic activities can be detected

  11. Depth-resolved residual stress evaluation from X-ray diffraction measurement data using the approximate inverse method

    CERN Document Server

    Schuster, T; Louis, A K

    2003-01-01

    The paper deals with the depth determination of residual stress states from diffraction data. First an historical overview of the known approaches is given. Then we apply the approximate inverse method to this problem. This method is known to be very efficient and stable with respect to noise-contaminated data. It is even possible to prove convergence and it allows an error estimate of the calculated depth resolved residual stress profile. (orig.)

  12. The difference of acrylic resin residual monomer levels with various polymerization method

    Directory of Open Access Journals (Sweden)

    Sherman Salim

    2011-12-01

    Full Text Available Background: After polymerization process, heat cured acrylic resin denture base actually still contains residual monomers that can become potential irritants later in oral cavity. Polymerization process is essential to obtain acrylic resin which can meet the requirements of the biocompatible and good physical properties. To meet the requirements, there are several methods of polymerization process used. Purpose: The purpose of this study was to determine the differences of the residual monomer levels of acrylic resin processed by various polymerization methods. Methods: Acrylic resin powder and liquid were mixed based on the rules of factory, and sample was made with size of 30 mm × 50 mm × 3 mm and then polymerized by using microwave at 70° C for 24 hours based on the methods of Japan Industrial Standard (JIS. Each group of samples was cut with weight of ± 0.2 g, dissolved in 5 ml of methyl ethyl ketone in test tubes, and then stored at ± 5° C for four days. Residual monomer level was conducted by using gas chromatograph mass spectrometer. Data obtained were then analyzed by using One-Way ANOVA test with p < 0.05. Results: After the level of polymerizing residual monomer with JIS method was compared to that at 70° C for 24 hours using microwave, it is known that there were significant differences (p < 0.05. Conclusion: The highest level of residual monomer of acrylic resin was that polymerized at 70° C for 24 hours.Latar belakang: Basis gigi tiruan yang berbahan dasar resin akrilik jenis heat cured setelah proses polimerisasi selesai masih mengandung monomer sisa yang berpotensi sebagai bahan iritan dalam rongga mulut. Proses polimerisasi sangat penting untuk mendapatkan resin akrilik yang memenuhi persyaratan biokompatibilitas dan fisik yang baik. Untuk persyaratan tersebut digunakan berbagai macam proses polimerisasi. Tujuan: Penelitian ini bertujuan untuk menentukan kadar monomer sisa resin akrilik yang diproses dengan metode

  13. Methods for conditioning wastes from spent fuel cans and dissolver residues

    International Nuclear Information System (INIS)

    De Regge, P.; Loida, A.; Schmidt-Hansberg, T.; Sombret, C.

    1985-04-01

    Several methods for conditioning spent fuel decladding hulls or dissolver residues have been considered in various countries of the European Community. Five of these methods use embedding technique with or without prior compaction: they are based on incorporation in metallic alloys, glass, ceramics, cements and metals or graphite compounds. A sixth one consists in melting the decladding materials. The corresponding research programs have been pursued to varying states of progress with regard to demonstrating their feasibility on an industrial scale and the use of genuine wastes in bench scale experiments. The properties of the conditioned wastes have been investigated. Special attention has been paid to the corrosion resistance to various aqueous media as tap water, brine or clayey water. Although no categorical conclusion can be drawn from the initial results, the available finding provide a basis for assessing the different processes [fr

  14. Method for identification of rigid domains and hinge residues in proteins based on exhaustive enumeration.

    Science.gov (United States)

    Sim, Jaehyun; Sim, Jun; Park, Eunsung; Lee, Julian

    2015-06-01

    Many proteins undergo large-scale motions where relatively rigid domains move against each other. The identification of rigid domains, as well as the hinge residues important for their relative movements, is important for various applications including flexible docking simulations. In this work, we develop a method for protein rigid domain identification based on an exhaustive enumeration of maximal rigid domains, the rigid domains not fully contained within other domains. The computation is performed by mapping the problem to that of finding maximal cliques in a graph. A minimal set of rigid domains are then selected, which cover most of the protein with minimal overlap. In contrast to the results of existing methods that partition a protein into non-overlapping domains using approximate algorithms, the rigid domains obtained from exact enumeration naturally contain overlapping regions, which correspond to the hinges of the inter-domain bending motion. The performance of the algorithm is demonstrated on several proteins. © 2015 Wiley Periodicals, Inc.

  15. Simultaneous Determination of TetracyclinesResidues in Bovine Milk Samples by Solid Phase Extraction and HPLC-FL Method

    Directory of Open Access Journals (Sweden)

    Mehra Mesgari Abbasi

    2011-06-01

    Full Text Available Introduction:Tetracyclines (TCs are widely used in animal husbandry and their residues in milk may resultinharmful effects on human. The aim of this study was to investigate the presence of TCs residues in various bovine milk samples from local markets of Ardabil, Iran. Methods:One hundred and fourteen pasteurized, sterilized and raw milk samples were collected from markets of Ardabil. Tetracycline, Oxytetracycline and Chlortetracycline (TCs residues extraction carried out by Solid Phase Extraction method. Determination of TCs residues were performed by high performance liquid chromatography (HPLC method using Fluorescence detector.Results: The mean of total TCs residues in all samples (114 samples was 97.6 ±16.9ng/g and that of pasteurized, sterilized and raw milk samples were 87.1 ± 17.7, 112.0 ± 57.3 and 154.0 ± 66.3ng/g respectively. Twenty five point four percent of the all samples, and24.4%, 30% and 28.6% of the pasteurized, sterilized and raw milk samples, respectively had higher TCs residues than the recommended maximum levels (100ng/g. Conclusion:This study indicates the presence of tetracycline residues more than allowed amount. Regulatory authorities should ensure proper withdrawal period before milking the animals and definite supervisions are necessary on application of these drugs.

  16. QuEChERS-based method for the determination of carbamate residues in aromatic herbs by UHPLC-MS/MS.

    Science.gov (United States)

    Nantia, Edouard Akono; Moreno-González, David; Manfo, Faustin P T; Gámiz-Gracia, Laura; García-Campaña, Ana M

    2017-02-01

    A new reliable, fast and highly sensitive method based on ultra-high performance liquid chromatography tandem mass spectrometry has been developed and validated for the determination of 28 carbamates in aromatic herbs. A modified QuEChERS-based method was optimized for the extraction of carbamate residues from a wide variety of fresh herbal products. The proposed method allowed recoveries higher than 72%, achieving quantification limits of 2μgkg(-1), therefore below maximum residue limits established for this type of samples. The combination of QuEChERS with UHPLC-MS/MS introduces a high-throughput methodology for the monitoring of these residues in this type of matrices scarcely explored. The analysis of the real samples revealed that several samples sold in the European Union and in the North West region of Cameroon contain pesticides in concentrations below the maximum residue limits. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Recovery of signal loss adopting the residual bootstrap method in fetal heart rate dynamics.

    Science.gov (United States)

    Lee, Sun-Kyung; Park, Young-Sun; Cha, Kyung-Joon

    2018-03-19

    Fetal heart rate (FHR) data obtained from a non-stress test (NST) can be presented in a type of time series, which is accompanied by signal loss due to physical and biological causes. To recover or estimate FHR data, which is subjected to a high rate of signal loss, time series models [second-order autoregressive (AR(2)), first-order autoregressive conditional heteroscedasticity (ARCH(1)) and empirical mode decomposition and vector autoregressive (EMD-VAR)] and the residual bootstrap method were applied. The ARCH(1) model with the residual bootstrap technique was the most accurate [root mean square error (RMSE), 2.065] as it reflects the nonlinearity of the FHR data [mean absolute error (MAE) for approximate entropy (ApEn), 0.081]. As a result, the goal of predicting fetal health and identifying a high-risk pregnancy could be achieved. These trials may be effectively used to save the time and cost of repeating the NST when the fetal diagnosis is impossible owing to a large amount of signal loss.

  18. Comparison of Measured Residual Stress in an Extra Thick Multi-pass Weld Using Neutron Diffraction Method and Inherent Strain Method

    International Nuclear Information System (INIS)

    Park, JeongUng; An, GyuBaek; Woo, Wan Chuck

    2015-01-01

    With the increase of large-scale containership, a large amount of high-strength steels with extra thick plates is being extensively used. The welding stress existing in the extra thick welded plates has a significant effect on the integrity of the component in terms of brittle fracture and fatigue behavior. It has been reported that welding residual stress distribution in an extra thick plate can affect the propagation path of the crack. Therefore, it is important to measure the distribution of welding residual stresses for the reliable design of the welded structures. So far various researches have been carried out for the determination of residual stresses on the surface of steels. In this paper, the total residual stresses in the 70 mm thick multipass FACW butt joint were measured by integrating initial stress into ISM. Concretely, two methods named as initial stress integrated ISM and initial inherent strain integrated ISM were employed to determine the total residual stresses. Furthermore, the distributions of residual stresses were compared with the results of the Neutron Diffraction Method(NDM). In order to measure the three dimensional residual stresses in the welded joint with initial stresses existing before welding, initial stress integrated ISM and initial inherent strain integrated ISM were developed. The residual stresses in 70 mm-thick butt joint by flux cored arc welding were carried out with a good accuracy using the two developed methods. The residual stresses in welded joint using both initial stress integrated ISM and initial inherent strain integrated ISM agreed well with the results measured by Neutron Diffraction Method. This suggests that the integrated ISM is a reliable method for residual stress measurement if initial stress existed

  19. Development and validation of an alternative to conventional pretreatment methods for residue analysis of butachlor in water, soil, and rice.

    Science.gov (United States)

    Xue, Jiaying; Jiang, Wenqing; Liu, Fengmao; Zhao, Huiyu; Wang, Suli; Peng, Wei

    2014-01-01

    A rapid and effective alternative analytical method for residues of butachlor in water, soil, and rice was established. The operating variables affecting performance of this method, including different extraction conditions and cleanup adsorbents, were evaluated. The determination of butachlor residues in soil, straw, rice hull, and husked rice was performed using GC/MS after extraction with n-hexane and cleanup with graphite carbon black. The average recoveries ranged from 81.5 to 102.7%, with RSDs of 0.6-7.7% for all of the matrixes investigated. The limits of quantitation were 0.05 mg/kg in water and rice plant, and 0.01 mg/kg in soil, straw, rice hull, and husked rice. A comparison among this proposed method, the conventional liquid-liquid extraction, the Quick, Easy, Cheap, Effective, Rugged, and Safe method, and Soxhlet extraction indicated that this method was more suitable for analyzing butachlor in rice samples. The further validation of the proposed method was carried out by Soxhlet extraction for the determination of butachlor residues in the husked rice samples, and the residue results showed there was no obvious difference obtained from these two methods. Samples from a rice field were found to contain butachlor residues below the maximum residue limits set by China (0.5 mg/kg) and Japan (0.1 mg/kg). The proposed method has a strong potential for application in routine screening and processing of large numbers of samples. This study developed a more effective alternative to the conventional analytical methods for analyzing butachlor residues in various matrixes.

  20. An In Vitro Comparison of Different Diagnostic Methods in Detection of Residual Dentinal Caries

    Directory of Open Access Journals (Sweden)

    Nimet Unlu

    2010-01-01

    Full Text Available The aim of this study was to investigate the efficiency of different diagnostic methods in detection of residual dentinal caries in excavated cavities. Fifty extracted molar with deep dentinal carious lesions were excavated using a slow-speed handpiece. All cavities were assessed by laser fluorescence(LF device, electronic caries monitor(ECM, and caries detector dye(CDD by three independent observers blindly. The measurements were repeated after two weeks. Specimens containing dentin slices 150 μm in thickness were prepared for histological analyses. The existence and absence of carious dentin was determined using a lightmicroscope. The average intraobserver accuracy was 1.00 (perfect agreement for CDD, 0.86 (excellent agreement for ECM, and 0.50 (good agreement for LF. The average interobserver accuracy values were 0.92 (excellent agreement, (0.36 marginal agreement and 0.48 (good agreement, for CDD, ECM, and LF, respectively. The average specificity was 0.60 for CDD, 73% for ECM, and 0.50 for LF. The average sensitivity was 0.55 for CDD, 0.85 for LF, and 0.47 for ECM. The average accuracy values were 0.53, 0.51, and 0.81 for CDD, ECM, and LF, respectively. LF had the greatest sensitivity and accuracy values of any of the methods tested. As a conclusion, LF device is appeared to most reliable method in detection of remain caries in cavity. However, because of its technical sensitivity it may susceptible to variations in measurements. To pay attention to the rule of usage and repeated measurements can minimize such variations in clinical practice. It was concluded that LF is an improvement on the currently available aids for residual caries detection.

  1. Investigation of antibiotic residues in edible tissues of slaughtered broilers in Maragheh abattoir using FPT method (short comunication

    Directory of Open Access Journals (Sweden)

    Masumeh Abasi

    2016-05-01

    Full Text Available Antibiotic residues in food stuff and their transmission to the consumers have some consequences such as bacterial resistance, allergic reactions, intoxication, carcinogenic effects and disturbing of intestine natural flora. Among microbiologic methods, four plate test (FPT is used to detect antibiotic residues in food stuff, which performs in four culture media with different pH values and test bacteria. The aim of this study was investigation of antibiotic residues in edible tissues of slaughtered broilers in Maragheh abattoir using FPT method. For this reason, 40 slaughtered broilers carcasses in Maragheh abattoir (from 10 different poultry farms were sampled. The sampling was conducted randomly from breast and leg muscles, gizzard as well as liver of each carcass. According to results of current study, 60% of liver samples, 55% of leg samples, 52.5% of breast samples and 52.5% of gizzard samples contained antibiotic residues. Moreover, the amount of antibiotic residues among different samples did not show statistical significance (p>0.05. The highest occurrence of antibiotic residue was found in two flocks (100% and the lowest occurrence was recorded for another two flocks (0%. According to the health hazard of antibiotic residues in foods, continuous monitoring is recommended for edible tissues of broilers.

  2. Non-destructive residual pressure self-measurement method for the sensing chip of optical Fabry-Perot pressure sensor.

    Science.gov (United States)

    Wang, Xue; Wang, Shuang; Jiang, Junfeng; Liu, Kun; Zhang, Xuezhi; Xiao, Mengnan; Xiao, Hai; Liu, Tiegen

    2017-12-11

    We introduce a simple residual pressure self-measurement method for the Fabry-Perot (F-P) cavity of optical MEMS pressure sensor. No extra installation is required and the structure of the sensor is unchanged. In the method, the relationship between residual pressure and external pressure under the same diaphragm deflection condition at different temperatures is analyzed by using the deflection formula of the circular plate with clamped edges and the ideal gas law. Based on this, the residual pressure under the flat condition can be obtained by pressure scanning process and calculation process. We carried out the experiment to compare the residual pressures of two batches MEMS sensors fabricated by two kinds of bonding process. The measurement result indicates that our approach is reliable enough for the measurement.

  3. Residual stress evaluation of austenitic stainless steel with a finished surface by polychromatic X-ray method

    Energy Technology Data Exchange (ETDEWEB)

    Shibano, Jun-ichi; Ukai, Takayoshi; Tadano, Shigeru [Hokkaido Univ., Sapporo (Japan). Faculty of Engineering; Todoh, Masahiro

    1995-11-01

    The residual stress in a subsurface layer of austenitic stainless steel with a finished surface was evaluated by the polychromatic X-ray method. A surface of austenitic stainless steel SUS316 plate was ground and lapped as the specimen. In this method, the relation between strain and depth was approximated with a linear function or an exponential function, and it was assumed that the plane stress state existed in each subsurface layer in the depth direction of the specimen. As a result, the residual strain which was estimated under the assumption of the exponential function showed more reasonable distribution than that of the linear function. In addition, the residual stress which was calculated from the strain distribution was maximum tension at the surface of the specimen, and maximum compression at a position 3 {mu}m below the surface. Therefore, the steep gradient of residual stress could be confirmed in a subsurface layer of the SUS316 with a finished surface. (author).

  4. Triaxial Measurement Method for Analysis of Residual Stress after High Feed Milling by X-Ray Diffraction

    Science.gov (United States)

    Čuma, Matúš; Török, Jozef; Telišková, Monika

    2016-12-01

    Surface integrity is a broad term which includes various quality factors affecting the functional properties of parts. Residual stress is one of these factors. Machining generates residual stresses in the surface and subsurface layers of the structural elements. X-ray diffractometry is a non-destructive method applicable for the measurement of residual stresses in surface and subsurface layers of components. The article is focused on the non-destructive progressive method of triaxial measurement of residual stress after machining the surface of sample by high feed milling technology. Significance of triaxial measuring is the capability of measuring in different angles so it is possible to acquire stress tensor containing normal and shear stress components acting in the spot of measuring, using a Cartesian coordinate system.

  5. Standard Test Method for Gravimetric Determination of Nonvolatile Residue (NVR) in Environmentally Controlled Areas for Spacecraft

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This test method covers the determination of nonvolatile residue (NVR) fallout in environmentally controlled areas used for the assembly, testing, and processing of spacecraft. 1.2 The NVR of interest is that which is deposited on sampling plate surfaces at room temperature: it is left to the user to infer the relationship between the NVR found on the sampling plate surface and that found on any other surfaces. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

  6. Standard Test Method for Gravimetric Determination of Nonvolatile Residue From Cleanroom Wipers

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 This test method covers the determination of solvent extractable nonvolatile residue (NVR) from wipers used in assembly, cleaning, or testing of spacecraft, but not from those used for analytical surface sampling of hardware. 1.2 The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. 1.3 The NVR of interest is that which can be extracted from cleanroom wipers using a specified solvent that has been selected for its extractive qualities. Alternative solvents may be selected, but since their use may result in different values being generated, they must be identified in the procedure data sheet. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  7. Comparison and evaluation of two methods for the pesticide residue analysis of organophosphates in yerba mate

    Directory of Open Access Journals (Sweden)

    Lucía Pareja

    Full Text Available Abstract Microwave Assisted Extraction and a modified CEN-QuEChERS methodology were evaluated as extraction and clean up procedures for the simultaneous analysis of 42 organophosphate pesticides in yerba mate (Ilex paraguaiensis. The obtained extracts were analyzed by gas chromatography using a flame photometric detector. Linearity, recovery percentages, relative standard deviations, detection and quantification limits and matrix effects were determined according to DG-SANCO guidelines for both methods. At 0.2 and 0.5 mg/kg the evaluated methods showed percentages recoveries between 70 and 120% for most of the analytes. Using Microwave Assisted Extraction methodology, 33 pesticide residues could be properly analyzed whereas only 27 could be determined with the proposed modified QuEChERS. All relative standard deviation were below 18% except for omethoate and disulfoton sulfone when evaluated by the modified QuEChERS. The limits of detection in both methodologies were 0.2 mg/kg for most of the analyzed compounds. The average detection limit for QuEChERS was 0.04 mg/kg. For 19 of the analytes determined through Microwave Assisted Extraction the lowest validated level were 0.004 mg/kg. Signal suppression/enhancement was observed for most of the pesticides, thus matrix-matched calibration curves were used for quantification. The Microwave Assisted Extraction and QuEChERS procedures studied could detect the organophosphate pesticides above the MRL fixed for "mate" by the European Union. They have been successfully applied for the determination of organophosphate pesticide residues in commercial samples and the positives were confirmed through GC–(ITD-MS.

  8. Multi-residue method for the determination of antibiotics and some of their metabolites in seafood.

    Science.gov (United States)

    Serra-Compte, Albert; Álvarez-Muñoz, Diana; Rodríguez-Mozaz, Sara; Barceló, Damià

    2017-06-01

    The presence of antibiotics in seafood for human consumption may pose a risk for consumers. A methodology for the analysis of antibiotics in seafood based on QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction, followed by detection and quantification using liquid chromatography coupled to mass spectrometry was developed. The analytical method was evaluated for the determination of 23 antibiotics (including parent compounds and some metabolites) in fish, mussels and clams. Recoveries ranged between 30% and 70% for most of the compounds and method detection and quantification limits (MDLs and MQLs) were between 0.01 and 0.31 ng/g dry weigh (dw) and 0.02-1.03 ng/g (dw) respectively. Real seafood samples were analysed using this method. Nine antibiotics were found at levels above MDLs; however none of them exceed the maximum residue limits (MRL) established by the authorities. Tetracycline was the most ubiquitous compound, presenting also the highest concentration: 5.63 ng/g (dw) in fish from Netherlands. In addition, an alternative technique based on microbial growth inhibition was explored as semiquantitative detection method of antibiotics in seafood. This methodology could be applied as a fast screening technique for the detection of macrolides and β-lactams in seafood but further research is needed for other antibiotics families. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Validation of a multi-residue method for the determination of residuals pesticides in cabbage (Brassica Oleracea var. Capitata) for gases chromatography

    International Nuclear Information System (INIS)

    Moreno, Milton Leonardo; Guerrero Dallos, Jairo Arturo

    2002-01-01

    This study describes the validation of a multi-residue method for the determination of most used organo chlorine, organophosphorus and organonitrogen pesticides in cabbage in the Cundinamarca Department (Colombia). The extraction process includes blending of small sample quantity with ethyl acetate in presence of Na 2 SO 4 and NaHCO 3 , filtration and concentration. The clean up steps include GPC and mini-column chromatography using silica gel. Final determination was carried out by gas chromatography with: pulsed splitless injection, HP-5 capillary column, and a parallel detection system with micro electron capture detection (μ - ECD) and Nitrogen-Phosphorus Detection (NPD). The methodology is specific, selective, accurate and robust. Recovery values of majority of pesticides were in the range 70-120% at spiking levels ranging 0.05-10.73 mg/kg. Limits of detection were less than 0.10 mg/kg for most of the studied compounds. The distribution of the analyses in the laboratory sample was evaluated and it was found its homogeneity. The evaluation of pesticide residues was made in a specific area of municipality of Madrid-Cundinamarca, (Colombia). No residues of the studied analyses were founded

  10. Application of the Rietveld method to assess chromium(VI) speciation in chromite ore processing residue.

    Science.gov (United States)

    Chrysochoou, Maria; Dermatas, Dimitris

    2007-03-15

    The Rietveld method allows the quantification of crystalline phases and amorphous material identified by X-ray powder diffraction (XRPD) and other diffraction methods. The method assists in determining the speciation of contaminants in solid matrices both qualitatively and quantitatively in a statistically defensible approach, as it does not focus on a microscale. Rietveld was applied to chromite ore processing residue (COPR), a cementitious waste containing hexavalent chromium. Calcium aluminum chromium oxide hydrates (CACs) were the crystalline phases identified by XRPD that bind Cr(6+) in COPR according to their chemical formula. Rietveld quantification, combined with mass balances on Cr(6+), showed that CACs may bind Cr(6+) in variable percentages, ranging from 25% to 85%. Analysis of duplicate samples showed that material variability is the predominant factor of uncertainty in evaluating the role of CACs in Cr(6+) speciation, provided that a consistent quantification strategy is pursued. The choice of strategy was performed on the basis of the pertinent literature, preliminary analyses of the equipment and the software settings, and mass balances. The correlation between the average CAC-bound Cr(6+) concentration and the total Cr(6+) for five samples (R(2)=0.94), extracted from different zones and soil borings, suggests that CACs are a primary sink for Cr(6+) in COPR.

  11. Improved Method for Quantifying Nonvolatile Residues on Surfaces and in Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Benkovich, M.G.

    2004-03-30

    The objective of the project was to develop an improved method to quantify nonvolatile residues on surfaces and in liquids. The project accomplishments are summarized below: (1) ERA Systems, Inc., The MESERAN Company has designed, developed, built, evaluated, tested, and delivered MicroSolventEvaporator systems to KCP, Astro Pak, and Lockheed Martin, that automatically deposit and evaporate successive small quantities (5-10 microliters) of solvents onto clean reference surfaces. (2) ERA Systems, Inc., The MESERAN Company, and KCP have designed, procured, and evaluated stainless steel disks with specific machined grooves to be used as reference surfaces with the MicroSolventEvaporator and MESERAN Analyzers. (3) KCP evaluated various cleaning processes to easily clean the reference surfaces to acceptable levels. Even though some methods (or a combination of methods) may have worked better than others, an easy method that most companies could use to acceptably clean the disks was desired. Aqueous ultrasonic cleaning with Dirl Lum 603 (30 g per liter concentration) followed by flowing DI water and ultrasonic DI water rinses, nitrogen blow drying, and baking in a HEPA filtered oven at 220 F for 30 minutes proved to be a relatively simple method that most companies could use. (4) KCP developed calibrations of several contaminants on the chosen reference substrates so the MESERAN data could be converted into quantifiable amounts of contamination. (5) KCP performed a prove-in of the MicroSolventEvaporator in conjunction with the MESERAN Analyzer and compared the results to gravimetric data. The method worked and was able to provide data at low contamination levels that can not be reliably obtained gravimetrically. (6) Astro Pak and Lockheed Martin have done limited testing at their facilities. The MESERAN Company has agreed to let them keep the units for awhile so they can continue to perform tests to prove-in the process at their facilities even after the CRADA is

  12. Multi-residue method for the confirmation of four avermectin residues in food products of animal origin by ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wang, Fengmei; Chen, Junhui; Cheng, Hongyan; Tang, Zhixu; Zhang, Gang; Niu, Zengyuan; Pang, Shiping; Wang, Xiaoru; Lee, Frank Sen-Chun

    2011-05-01

    A confirmatory method was developed for the rapid determination of abamectin, ivermectin, doramectin and eprinomectin residues in various food products of animal origin, such as pork muscle, pork liver, fish and milk. Samples were homogenized, extracted and de-proteinized by acetonitrile, cleaned via two-step cleaning procedure using Bond Elut C(18) SPE columns and then alumina-N cartridges. All the four avermectin residues in different animal-food products were simultaneously separated and determined by ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) within 3.5 min. Data acquisition under positive ESI-MS/MS was performed by applying multiple reaction monitoring (MRM) for both identification and quantification, and mass spectrometric conditions were optimized to increase selectivity and sensitivity. The matrix-matched calibration curves for different matrices, such as pork muscle, pork liver, fish and milk, were constructed and the interference effect of different sample matrices on the ionization was effectively eliminated. The UPLC-MS/MS method was validated with satisfactory linearity, recovery, precision and stability. Matrix-matched calibration curves of abamectin, ivermectin, doramectin and eprinomectin in four different matrices were linear (r(2)( )≥ 0.990, goodness-of-fit coefficients ≤12.8%) in the range 2.5-200 µg kg(-1). The limits of detection and quantification for the four avermectins were in the range 0.05-0.68 and 0.17-2.27 µg kg(-1), respectively. Recoveries were 62.4-104.5% with good intra- and inter-day precision. The method was rapid, sensitive and reliable, and can be applied to the quantitative analysis of avermectin residues in different animal-food products.

  13. Minimization and Mitigation of Wire EDM Cutting Errors in the Application of the Contour Method of Residual Stress Measurement

    Science.gov (United States)

    Ahmad, Bilal; Fitzpatrick, Michael E.

    2016-01-01

    The contour method of residual stress measurement relies on the careful application of wire electro-discharge machining (WEDM) for the cutting stage. Changes in material removal rates during the cut lead to errors in the final calculated values of residual stress. In this study, WEDM cutting parameters have been explored to identify the optimum conditions for contour method residual stress measurements. The influence of machine parameters on the surface roughness and cutting artifacts in the contour cut is discussed. It has been identified that the critical parameter in improving the surface finish is the spark pulse duration. A typical cutting artifact and its impact on measured stress values have been identified and demonstrated for a contour cut in a welded marine steel. A procedure is presented to correct contour displacement data from the influence of WEDM cutting artifacts, and is demonstrated on the correction of a measured weld residual stress. The corrected contour method improved the residual stress magnitude up to 150 MPa. The corrected contour method results were validated by X-ray diffraction, incremental center hole drilling, and neutron diffraction.

  14. [A smear method for measuring anti-cancer drugs residues in hospitals].

    Science.gov (United States)

    Takano, Takumi; Suzuki, Shigeru; Tsukiyama, Ikuto; Saito, Hiroko

    2015-01-01

    Anti-cancer drugs are harmful to healthy persons. In recent years, occupational exposure to anti-cancer drugs has become a major concern to health care workers. To address this issue, a smear method was developed to measure widely using anti-cancer drugs depositing on the floors, safety cabinet surfaces, and tables in hospital. Ten kinds of widely used anti-cancer drugs, paclitaxel, vincristine, docetaxel, vinorelbine, irinotecan, methotrexate, oxaliplatin, cyclophosphamide, gemcitabine and fluorouracil were collected by smearing material surfaces with methanol impregnated cellulose filter paper and/or polypropylene nonwoven. The collected anti-cancer drugs are extracted in 5 ml of 0.01% (v/v) hydrazine/methanol solution by sonication. The extracted solution was filtered and concentrated to prepare 1ml of sample solution. Then, the anti-cancer drugs in the sample solution were simultaneously measured by LC/MS. The anti-cancer drugs excepting fluorouracil spread on P-tile surface were measured with recoveries of 37-101% and standard deviations (SD) of 1.8-19%. All 10 of the anti-cancer drugs on a stainless steel plate surface were measured with the recoveries of 35-111% and SD of 1.3-11%. Using this smear method, 9 or 10 kinds of widely used anti-cancer drug residues in hospital, possibly exposed to health care workers, were grasped.

  15. A method for determining allowable residual contamination levels of radionuclide mixtures in soil

    International Nuclear Information System (INIS)

    Napier, B.A.

    1982-05-01

    An important consideration in the disposal of radioactive wastes, and consequently in the preparation of plans for remedial actions at contaminated sites, is the amount of radioactive contamination that may be allowed to remain at any particular waste site. The allowable residual contamination level (ARCL) is dependent on the radiation dose limit imposed, the physical and environmental characteristics of the waste site, and the time at which exposure to the wastes is assumed to occur. The steps in generating an ARCL are generally as follows: (1) develop plausible, credible site-specific exposure scenario; (2) calculate maximum annual radiation doses to an individual for each radionuclide based on the existing physical characteristics of the waste site and the site-specific exposure scenario; (3) calculate the ARCL for the dose limit desired, including all radionuclides present, uncorrected for site cleanup or barrier considerations; and (4) apply any corrections for proposed cleanup activity or addition of barriers to waste migration or uptake to obtain the ARCL applicable to the proposed action. Use of this method allows appropriate application of resources to achieve uniform compliance with a single regulatory standard, i.e., a radiation dose rate limit. Application and modification of the ARCL method requires appropriate models of the environmental transport and fate of radionuclides. Example calculations are given for several specific waste forms and waste site types in order to demonstrate the technique and generate comparisons with other approaches

  16. [Multi-residue method for determination of veterinary drugs and feed additives in meats by HPLC].

    Science.gov (United States)

    Chonan, Takao; Fujimoto, Toru; Ueno, Ken-Ichi; Tazawa, Teijiro; Ogawa, Hiroshi

    2007-10-01

    A simple and rapid multi-residue method was developed for the determination of 28 kinds of veterinary drugs and feed additives (drugs) in muscle of cattle, pig and chicken. The drugs were extracted with acetonitrile-water (95:5) in a homogenizer and ultrasonic generator. The extracted solution was poured into an alumina column and the drugs were eluted with acetonitrile-water (90:10). The eluate was washed with n-hexane saturated with acetonitrile and then evaporated. The drugs were separated on a Inertsil ODS-3V column (4.6 mm i.d. x 250 mm) with a gradient system of 0.1% phosphoric acid-acetonitrile as the mobile phase, with monitoring at 280 and 340 nm. The recoveries of the 26 kinds of drugs were over 60% from the meats fortified at 0.1 microg/g, and the quantification limits of most drugs were 0.01 microg/g. This proposed method was found to be effective and suitable for the screening of the above drugs in meats.

  17. Study of TATP: method for determination of residual acids in TATP.

    Science.gov (United States)

    Matyáš, Robert; Chýlková, Jaromíra

    2013-05-10

    Triacetone triperoxide (3,3,6,6,9,9-hexamethyl-1,2,4,5,7,8-hexoxonane, TATP) is nowadays one of the most commonly used improvised explosives. It is prepared by the action of hydrogen peroxide on acetone in an acidic environment. Easily available mineral acids - hydrochloric, sulfuric, nitric and perchloric - are the most often recommended on the extremist web pages dealing with improvised production of explosives. The various TATP producers' choice of acid mainly depends on the author's experiences and the local availability of the acid. A knowledge of the kind of acid used for TATP production can help in detecting the person who has made the TATP, or who has committed a criminal act using TATP. Therefore, a capillary isotachophoretic method was developed for determination of residual anions (originating from the acid used during TATP synthesis) in the resulting TATP crystals. This analytical method has proved to be reliable; the acid used for TATP synthesis was correctly identified in all samples analyzed. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  18. A direct recursive residue generation method: application to photoionization of hydrogen in static electric fields

    International Nuclear Information System (INIS)

    Karlsson, H.O.; Goscinski, O.

    1994-01-01

    In studies of hydrogenic systems via the recursive residue generation method (RRGM) the major bottleneck is the matrix vector product HC, between the Hamiltonian matrix H and a Lanczos vector C. For highly excited states and/or strong perturbations the size of H grows fast leading to storage problems. By making use of direct methods, i.e. avoidance of explicit construction of large Hamiltonian matrices, such problems can be overcome. Utilizing the underlying analytical properties of the Laguerre basis e -λr L k 2l+2 (2λr) a direct RRGM (D-RRGM) for the unperturbed hydrogenic Hamiltonian is derived, changing the storage needs from scaling as N 2 to 4N where N is the number of radial functions for each factorized H o (l,m) block with the possibility of parallel processing. A further computational simplification is introduced by putting the expression for the photoionization (PI) cross section in the rational form conventionally used in the representation of density of states (DOS). This allows the construction of the PI cross section directly from the tridiagonal Lanczos matrix avoiding the explicit calculation of individual eigen values and eigenvectors. (Author)

  19. Standard test method for determining the effective elastic parameter for X-ray diffraction measurements of residual stress

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1998-01-01

    1.1 This test method covers a procedure for experimentally determining the effective elastic parameter, Eeff, for the evaluation of residual and applied stresses by X-ray diffraction techniques. The effective elastic parameter relates macroscopic stress to the strain measured in a particular crystallographic direction in polycrystalline samples. Eeff should not be confused with E, the modulus of elasticity. Rather, it is nominally equivalent to E/(1 + ν) for the particular crystallographic direction, where ν is Poisson's ratio. The effective elastic parameter is influenced by elastic anisotropy and preferred orientation of the sample material. 1.2 This test method is applicable to all X-ray diffraction instruments intended for measurements of macroscopic residual stress that use measurements of the positions of the diffraction peaks in the high back-reflection region to determine changes in lattice spacing. 1.3 This test method is applicable to all X-ray diffraction techniques for residual stress measurem...

  20. A study on the neoasozine residues in rice grain by neutron activation method

    International Nuclear Information System (INIS)

    Kim, Y.H.; Lee, K.J.; Lee, S.R.

    1981-01-01

    Residues of neoasozine in rice grain were determined by neutron activation and colorimetric techniques. Twice application of the chemical before flowering did not lead to any increased residue level while 4-times application resulted in significant increase in the residue level up to 0.54 - 0.75 mg As 2 O 3 /kg. The partition ratio of arsenic residues into polished rice grain and bran was 73 : 27 in 100 % polishing while most of the residues in the bran was transferred to oil cake fraction during solvent extraction, reaching up to 2.9 mg As 2 O 3 /kg. The neutron activation technique was advantageous because of its high sensitivity and the smaller sample amounts required for analysis. (author)

  1. Residual nilpotence and residual solubility of groups

    International Nuclear Information System (INIS)

    Mikhailov, R V

    2005-01-01

    The properties of the residual nilpotence and the residual solubility of groups are studied. The main objects under investigation are the class of residually nilpotent groups such that each central extension of these groups is also residually nilpotent and the class of residually soluble groups such that each Abelian extension of these groups is residually soluble. Various examples of groups not belonging to these classes are constructed by homological methods and methods of the theory of modules over group rings. Several applications of the theory under consideration are presented and problems concerning the residual nilpotence of one-relator groups are considered.

  2. More on Generalizations and Modifications of Iterative Methods for Solving Large Sparse Indefinite Linear Systems

    Directory of Open Access Journals (Sweden)

    Jen-Yuan Chen

    2014-01-01

    Full Text Available Continuing from the works of Li et al. (2014, Li (2007, and Kincaid et al. (2000, we present more generalizations and modifications of iterative methods for solving large sparse symmetric and nonsymmetric indefinite systems of linear equations. We discuss a variety of iterative methods such as GMRES, MGMRES, MINRES, LQ-MINRES, QR MINRES, MMINRES, MGRES, and others.

  3. Validation of an HPLC–UV method for the determination of digoxin residues on the surface of manufacturing equipment

    Directory of Open Access Journals (Sweden)

    ZORAN B. TODOROVIĆ

    2009-09-01

    Full Text Available In the pharmaceutical industry, an important step consists in the removal of possible drug residues from the involved equipments and areas. The cleaning procedures must be validated and methods to determine trace amounts of drugs have, therefore, to be considered with special attention. An HPLC–UV method for the determination of digoxin residues on stainless steel surfaces was developed and validated in order to control a cleaning procedure. Cotton swabs, moistened with methanol were used to remove any residues of drugs from stainless steel surfaces, and give recoveries of 85.9, 85.2 and 78.7 % for three concentration levels. The precision of the results, reported as the relative standard deviation (RSD, were below 6.3 %. The method was validated over a concentration range of 0.05–12.5 µg mL-1. Low quantities of drug residues were determined by HPLC–UV using a Symmetry C18 column (150´4.6 mm, 5 µm at 20 °C with an acetonitrile–water (28:72, v/v mobile phase at a flow rate of 1.1 mL min-1, an injection volume of 100 µL and were detected at 220 nm. A simple, selective and sensitive HPLC–UV assay for the determination of digoxin residues on stainless steel was developed, validated and applied.

  4. An accurate method for determining residual stresses with magnetic non-destructive techniques in welded ferromagnetic steels

    Science.gov (United States)

    Vourna, P.

    2016-03-01

    The scope of the present research work was to investigate the proper selection criteria for developing a suitable methodology for the accurate determination of residual stresses existing in welded parts. Magnetic non-destructive testing took place by the use of two magnetic non-destructive techniques: by the measurement of the magnetic Barkhausen noise and by the evaluation of the magnetic hysteresis loop parameters. The spatial distribution of residual stresses in welded metal parts by both non-destructive magnetic methods and two diffraction methods was determined. The conduction of magnetic measurements required an initial calibration of ferromagnetic steels. Based on the examined volume of the sample, all methods used were divided into two large categories: the first one was related to the determination of surface residual stress, whereas the second one was related to bulk residual stress determination. The first category included the magnetic Barkhausen noise and the X-ray diffraction measurements, while the second one included the magnetic permeability and the neutron diffraction data. The residual stresses determined by the magnetic techniques were in a good agreement with the diffraction ones.

  5. Residual Stress Analysis of Severe Plastic Deformed Materials using the Finite Element Method and the Neutron Diffraction Method

    International Nuclear Information System (INIS)

    Kang, Mi Hyun; Seong, Back Suck; Kim, Hyoung Seop

    2009-01-01

    Severe plastic deformation (SPD) is one of the most promising top-down techniques, moving towards industrialization to fabricate bulk ultrafine grain materials. The strain distribution and deformation behavior during the ECAP (equal channel angular pressing), influenced by tool angles, friction and material behavior, was studied through experimental and numerical analyses. The residual stress of work piece which was straight before ECAP produces many serious problems in the next processing e.g. input of the work piece for the next ECAP. The bent work piece needs additional straightening or surface polishing even if the amount of bending is small, and residual stress need to be released before service applications. Residual stress, particularly tensile residual stress can be a very important factor in affecting the reliability and integrity of working parts. The formation of tensile residual stress may result in initiation of fatigue cracks, stress corrosion cracking, or other types of fracture. Hence, residual stress and resulting bending need to be controlled during ECAP. Thus, in current study the bending behavior and the residual stress of the work piece in ECAP are analyzed through experimental and finite element analyses by considering the effects of material, geometric, and processing parameters individually. The stress states in the ECAP processed work piece were measured by the non-destructive way using neutron diffraction. Efforts were made to suggest the alternate routes to reduce the residual stress and bending of work piece in ECAP

  6. Development and primary application of ELISA method for detecting residual calf serum protein

    International Nuclear Information System (INIS)

    Li Hua; Yu Jiankun; Hong Chao; Long Ruixiang; Zhai Yougang; Xu Qiongfang; Cui Pingfang; Ding Xuefeng; Xie Zhongping

    2005-01-01

    To develop a new DAS-ELISA (double antibody sandwich ELISA) kit for detecting residual calf serum protein (CSP) in vaccines, calf sera from different district were pooled and used to immunize rabbits and hens respectively. Then, the IgY from yolk and the anti-CSP IgG from rabbit were separated and purified. The purified IgY was used as the coating antibody, and purified rabbit anti-CSP IgG was labeled by HRP. The optimal concentration of IgY was 25-30 μg/mL. The coating buffer was 0.01mol/L PBS(pH7.4) containing 0.4% glutin. The optimal dilutions of HRP-IgG were from 1:2000 to 1:3000. The sensitivity of this ELISA method was higher (up to 2.5μg/mL) than that of current RPHA, the variation coefficient was about 6.3%-9.4%, and the recovery rate was 90.4%-112.8%. Furthermore, there was no cross-reaction with sera of pig, monkey and guinea pig. Twenty lots of vaccines with Al(OH) 3 or without Al(OH) 3 were tested by ELISA and RPHA respectively. The results proved that the adjuvant of Al(OH) 3 had fewer influence on ELISA than on RPHA, the variation of PRHA among different lots of vaccines was more significant than ELISA. The ELISA method is a highly sensitive and useful method to detect CSP in vaccines. (authors)

  7. Standard Test Method for Gravimetric Determination of Nonvolatile Residue from Cleanroom Gloves

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This test method covers the determination of solvent extractable nonvolatile residue (NVR) from gloves used in cleanrooms where spacecraft are assembled, cleaned, or tested. 1.2 The NVR of interest is that which can be extracted from gloves using a specified solvent that has been selected for its extracting qualities, or because it is representative of solvents used in the particular facility. Alternative solvents may be used, but since their use may result in different values being generated, they must be identified in the procedure data sheet. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  8. Computation of point reactor dynamics equations with thermal feedback via weighted residue method

    International Nuclear Information System (INIS)

    Suo Changan; Liu Xiaoming

    1986-01-01

    Point reactor dynamics equations with six groups of delayed neutrons have been computed via weighted-residual method in which the delta function was taken as a weighting function, and the parabolic with or without exponential factor as a trial function respectively for an insertion of large or smaller reactivity. The reactivity inserted into core can be varied with time, including insertion in forms of step function, polynomials up to second power and sine function. A thermal feedback of single flow channel model was added in. The thermal equations concerned were treated by use of a backward difference technique. A WRK code has been worked out, including implementation of an automatic selection of time span based on an input of error requirement and of an automatic change between computation with large reactivity and that with smaller one. On the condition of power varied slowly and without feedback, the results are not sensitive to the selection of values of time span. At last, the comparison of relevant results has shown that the agreement is quite well

  9. Prediction of Gas Chromatography-Mass Spectrometry Retention Times of Pesticide Residues by Chemometrics Methods

    Directory of Open Access Journals (Sweden)

    Elaheh Konoz

    2013-01-01

    Full Text Available A quantitative structure-retention relationships (QSRRs method is employed to predict the retention time of 300 pesticide residues in animal tissues separated by gas chromatography-mass spectroscopy (GC-MS. Firstly, a six-parameter QSRR model was developed by means of multiple linear regression. The six molecular descriptors that were considered to account for the effect of molecular structure on the retention time are number of nitrogen, Solvation connectivity index-chi 1, Balaban Y index, Moran autocorrelation-lag 2/weighted by atomic Sanderson electronegativity, total absolute charge, and radial distribution function-6.0/unweighted. A 6-7-1 back propagation artificial neural network (ANN was used to improve the accuracy of the constructed model. The standard error values of ANN model for training, test, and validation sets are 1.559, 1.517, and 1.249, respectively, which are less than those obtained reveals by multiple linear regressions model (2.402, 1.858, and 2.036, resp.. Results obtained the reliability and good predictability of nonlinear QSRR model to predict the retention time of pesticides.

  10. Properties of nanocellulose isolated from corncob residue using sulfuric acid, formic acid, oxidative and mechanical methods.

    Science.gov (United States)

    Liu, Chao; Li, Bin; Du, Haishun; Lv, Dong; Zhang, Yuedong; Yu, Guang; Mu, Xindong; Peng, Hui

    2016-10-20

    In this work, nanocellulose was extracted from bleached corncob residue (CCR), an underutilized lignocellulose waste from furfural industry, using four different methods (i.e. sulfuric acid hydrolysis, formic acid (FA) hydrolysis, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation, and pulp refining, respectively). The self-assembled structure, morphology, dimension, crystallinity, chemical structure and thermal stability of prepared nanocellulose were investigated. FA hydrolysis produced longer cellulose nanocrystals (CNCs) than the one obtained by sulfuric acid hydrolysis, and resulted in high crystallinity and thermal stability due to its preferential degradation of amorphous cellulose and lignin. The cellulose nanofibrils (CNFs) with fine and individualized structure could be isolated by TEMPO-mediated oxidation. In comparison with other nanocellulose products, the intensive pulp refining led to the CNFs with the longest length and the thickest diameter. This comparative study can help to provide an insight into the utilization of CCR as a potential source for nanocellulose production. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Evaluation of sodium hydrosulfite residue in sugar crop in Zanjan province and investigation the new alternative method for determination

    Directory of Open Access Journals (Sweden)

    M Mohseni

    2015-02-01

    Full Text Available Sodium hydrosulfite/blanket is used as a decolorizing agent for the bleaching of produced sugar in the sugar industry. Due to sensitivity of using this chemical substance with defined allowed range in sugar product, the sensitive and exact method of voltammetry/polarography was used to measure the residual blanket in this product and moreover, its results were compared with titration method as a common method for measurement of this substance in reference laboratories. Among the active sugar plants in Zanjan province, three different samples of loaf sugar batch were selected from each production unit based on sampling method of Standard and Industrial Research of Iran and all samples were evaluated using polarography 797 VA Computrace. Then, some of the samples evaluated by the polarography method were also checked with titration method and the results of the two methods were compared with each other. Statistical analysis of obtained data from polarography method shows that various sugar factories have different average sugar content values in blanket residual. Comparative system shows that titration method gives a more than usual response to the amount of blanket residual. Polarography method shows that the dithionite content in the samples ranged from

  12. Tailoring diffraction technique Rietveld method on residual stress measurements of cold-can oiled 304 stainless steel plates

    International Nuclear Information System (INIS)

    Parikin; Killen, P.; Anis, M.

    2003-01-01

    Tailoring of diffraction technique-Rietveld method on residual stress measurements of cold-canailed stainless steel 304 plates assuming the material is isotopic, the residual stress measurements using X-ray powder diffraction is just performed for a plane lying in a large angle. For anisotropic materials, the real measurements will not be represented by the methods. By Utilizing of all diffraction peaks in the observation region, tailoring diffraction technique-Rietveld analysis is able to cover the limitations. The residual stress measurement using X-ray powder diffraction tailored by Rietveld method, in a series of cold-canailed stainless steel 304 plates deforming; 0, 34, 84, 152, 158, 175, and 196 % reduction in thickness, have been reported. The diffraction data were analyzed by using Rietveld structure refinement method. Also, for all cold-canailed stainless steel 304 plates cuplikans, the diffraction peaks are broader than the uncanailed one, indicating that the strains in these cuplikans are inhomogeneous. From an analysis of the refined peak shape parameters, the average root-mean square strain, which describes the distribution of the inhomogeneous strain field, was calculated. Finally, the average residual stresses in cold-canailed stainless steel 304 plates were shown to be a combination effect of hydrostatic stresses of martensite particles and austenite matrix. The average residual stresses were evaluated from the experimentally determined average lattice strains in each phase. It was found the tensile residual stress in a cuplikan was maximum, reaching 442 MPa, for a cuplikan reducing 34% in thickness and minimum for a 196% cuplikan

  13. A Simple Surface-Enhanced Raman Spectroscopic Method for on-Site Screening of Tetracycline Residue in Whole Milk

    Directory of Open Access Journals (Sweden)

    Sagar Dhakal

    2018-02-01

    Full Text Available Therapeutic and subtherapeutic use of veterinary drugs has increased the risk of residue contamination in animal food products. Antibiotics such as tetracycline are used for mastitis treatment of lactating cows. Milk expressed from treated cows before the withdrawal period has elapsed may contain tetracycline residue. This study developed a simple surface-enhanced Raman spectroscopic (SERS method for on-site screening of tetracycline residue in milk and water. Six batches of silver colloid nanoparticles were prepared for surface enhancement measurement. Milk-tetracycline and water-tetracycline solutions were prepared at seven concentration levels (1000, 500, 100, 10, 1, 0.1, and 0.01 ppm and spiked with silver colloid nanoparticles. A 785 nm Raman spectroscopic system was used for spectral measurement. Tetracycline vibrational modes were observed at 1285, 1317 and 1632 cm−1 in water-tetracycline solutions and 1322 and 1621 cm−1 (shifted from 1317 and 1632 cm−1, respectively in milk-tetracycline solutions. Tetracycline residue concentration as low as 0.01 ppm was detected in both the solutions. The peak intensities at 1285 and 1322 cm−1 were used to estimate the tetracycline concentrations in water and milk with correlation coefficients of 0.92 for water and 0.88 for milk. Results indicate that this SERS method is a potential tool that can be used on-site at field production for qualitative and quantitative detection of tetracycline residues.

  14. A method for the determination of residual beta activity in drinking water samples

    Energy Technology Data Exchange (ETDEWEB)

    Idoeta, R. [Dpto. Ingenieria Nuclear y Mecanica de Fluidos, E. T. S. Ingenieria de Bilbao - Universidad del Pais Vasco (UPV/EHU), Alda. Urquijo s/n. 48013 Bilbao (Spain)], E-mail: raquel.idoeta@ehu.es; Herranz, M.; Abelairas, A.; Legarda, F. [Dpto. Ingenieria Nuclear y Mecanica de Fluidos, E. T. S. Ingenieria de Bilbao - Universidad del Pais Vasco (UPV/EHU), Alda. Urquijo s/n. 48013 Bilbao (Spain)

    2007-09-15

    The determination of residual beta activity in drinking water is usually needed in most monitoring programs. In this work a procedure for its determination is described and expressions for the calculations of detection limits and uncertainties are proposed.

  15. A method for the determination of residual beta activity in drinking water samples

    International Nuclear Information System (INIS)

    Idoeta, R.; Herranz, M.; Abelairas, A.; Legarda, F.

    2007-01-01

    The determination of residual beta activity in drinking water is usually needed in most monitoring programs. In this work a procedure for its determination is described and expressions for the calculations of detection limits and uncertainties are proposed

  16. The effect of peritoneal dialysis method on residual renal function in children.

    Science.gov (United States)

    Roszkowska-Blaim, Maria; Skrzypczyk, Piotr; Jander, Anna; Tkaczyk, Marcin; Bałasz-Chmielewska, Irena; Zurowska, Aleksandra; Drozdz, Dorota; Pietrzyk, Jacek A

    2012-01-01

    We set out to assess the effect of continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD) on residual renal function (RRF) in children with end-stage renal disease (ESRD). In 101 children (age: 8.84 +/- 5.25 years; 44 on CAPD, 57 on APD) over 36 months, we evaluated RRF [as daily diuresis (DD) in mL/kg/24 h and mL/m2/24 h], glomerular filtration rate [GFR (in mL/min/1.73 m2)], ESRD cause, presence of arterial hypertension (HTN), biochemical parameters, peritoneal equilibration test (PET), adequacy [as total weekly Kt/V (twKt/V) and creatinine clearance (twCCr)], and infectious complications of PD. Initially, the CAPD and APD groups did not differ significantly in DD, but mean GFR was significantly higher in the APD group (p uremic syndrome (HUS) and hereditary nephropathy were at the highest anuria risk. Compared with the 22 children (7 CAPD, 15 APD) who became anuric, the 20 children (10 CAPD, 10 APD) with RRF preserved for 36 months had a higher DD and GFR before dialysis onset; higher hemoglobin and albumin; and lower HTN prevalence, cholesterol, triglycerides, and proteinuria (p dialysis onset, HTN, anemia, hypoalbuminemia, hyperlipidemia, and proteinuria. Compared with children on APD, those on CAPD show better preservation of RRF during year 1, although the risk of anuria seems to be the same for both methods. In children with risk factors for rapid diuresis loss, CAPD might be considered the preferred initial dialysis method.

  17. Residual Stress in Wheels: Comparison of Neutron Diffraction and Ultrasonic Methods, with Trends in RCF

    OpenAIRE

    Molyneux-Berry, Paul; Bevan, Adam; Zhang, S. Y; Kabra, S

    2014-01-01

    The critical damage mechanism on many GB passenger train wheels is Rolling Contact Fatigue (RCF) cracking in the rim. Evidence from field observations suggests that RCF damage occurs much more quickly as the wheelsets near the end of their life. Wheel manufacturing processes induce a compressive hoop stress in the wheel rim; variations in residual stress through the life of a wheel may influence the observed RCF damage rates.\\ud This paper describes experiments to measure residual stresses in...

  18. Field kit and method for testing for the presence of gunshot residue

    Energy Technology Data Exchange (ETDEWEB)

    Rodacy, Philip J.; Walker, Pamela K.

    2003-09-02

    A field test kit for gunshot residue comprises a container having at least compartments separated by a barrier. A surface is tested by wiping it with a swab and placing the swab in a first compartment. The barrier is then breached, permitting reagent in the second compartment to flow onto the swab. The first compartment is transparent, and a color change will be observed if the reagent reacts with gunshot residue.

  19. Development of iterative techniques for the solution of unsteady compressible viscous flows

    Science.gov (United States)

    Sankar, Lakshmi; Hixon, Duane

    1993-01-01

    The work done under this project was documented in detail as the Ph. D. dissertation of Dr. Duane Hixon. The objectives of the research project were evaluation of the generalized minimum residual method (GMRES) as a tool for accelerating 2-D and 3-D unsteady flows and evaluation of the suitability of the GMRES algorithm for unsteady flows, computed on parallel computer architectures.

  20. Multiclass methods for the analysis of antibiotic residues in milk by liquid chromatography coupled to mass spectrometry: A review.

    Science.gov (United States)

    Rossi, Rosanna; Saluti, Giorgio; Moretti, Simone; Diamanti, Irene; Giusepponi, Danilo; Galarini, Roberta

    2018-02-01

    Milk is an important and beneficial food from a nutritional point of view, being an indispensable source of high quality proteins. Furthermore, it is a raw material for many dairy products, such as yoghurt, cheese, cream etc. Before reaching consumers, milk goes through production, processing and circulation. Each step involves potentially unsafe factors, such as chemical contamination that can affect milk quality. Antibiotics are widely used in veterinary medicine for dry cow therapy and mastitis treatment in lactating cows, which can cause the presence of antimicrobial residues in milk. In order to ensure consumers' safety, milk is analyzed to make sure that the fixed Maximum Residue Limits (MRLs) for antibiotics are not exceeded. Multiclass methods can monitor more drug classes through a single analysis, so they are faster, less time-consuming and cheaper than traditional methods (single-class); this aspect is particularly important for milk, which is a highly perishable food. Nevertheless, multiclass methods for veterinary drug residues in foodstuffs are real analytical challenges. This article reviews the major multiclass methods published for the determination of antibiotic residues in milk by liquid chromatography coupled to mass spectrometry, with a special focus on sample preparation approaches.

  1. A simple measurement of the Ni-63 diffusion profiles by residual activity method using a liquid scintillation counter

    Czech Academy of Sciences Publication Activity Database

    Rothová, Věra

    2013-01-01

    Roč. 729, NOV (2013), s. 702-706 ISSN 0168-9002 Institutional support: RVO:68081723 Keywords : Nickel-63 * Low-energy β-emitter * Solid scintillation counting * Diffusion * Gruzin′s residual activity method Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.316, year: 2013

  2. Investigating the Composite Step Biconjugate A-Orthogonal Residual Method for Non-Hermitian Dense Linear Systems in Electromagnetics

    NARCIS (Netherlands)

    Jing, Yan-Fei; Huang, Ting-Zhu; Carpentieri, Bruno; Duan, Yong

    An interesting stabilizing variant of the biconjugate A-orthogonal residual (BiCOR) method is investigated for solving dense complex non-Hermitian systems of linear equations arising from the Galerlcin discretization of surface integral equations in electromagnetics. The novel variant is naturally

  3. Review on Sources and Handling Method of Pesticide Residues in Animal Products

    Directory of Open Access Journals (Sweden)

    Indraningsih

    2006-06-01

    Full Text Available Field studies and literature search showed that some pesticide residues either organochlorines (OC or organophosphates (OP were detected in animal products (meat and milk . Pesticide residues in meat collected from West Java were detected at the level of 0 .8 ppb lindane and 62 ppb diazinon . While in meat from Lampung was detected at the level of 7 ppb lindane . 2 .7 heptachlor, 0 .8 endosulfan and 0 .5 ppb aldrin . Furthermore, pesticide residues were also detected in the milk collected from West, Central and East Java . The levels of lindane were 2,3 ; 15,9 ; 0,2 ppb ; heptachlor 8 ; 0 .4 and 0,05 ppb; diazinon 8 ; 0 and 1,8 ppb; CPM 0,4 ; 0,8 and 0 ppb ; endosulfan 0,1 ; 0,04 and 0,05 ppb for West, Central and East Java, respectively . The source of pesticide contamination in animal products is generally originated from feed materials, fodders . contaminated soils and water around the farm areas . Minimalization approach of pesticide residues in animal products could be conducted integratedly, such as through chemical process, biodegradation using microorganisms . Organic farming system is recognised as an alternative that may be applied to minimise contamination on agricultural land, eventually reducing pesticide residues in the agricultural products . Feeding with organic agricultural by-products with low pesticide residues appears to reduce pesticide residues in animal products . In order to eliminate pesticide contamination in soil, it has to be conducted progressively by implementing sustainable organic farming .

  4. Influence of digestion methods on the recovery of Iron, Zinc, Nickel, Chromium, Cadmium and Lead contents in 11 organic residues

    Directory of Open Access Journals (Sweden)

    Thalita Fernanda Abbruzzini

    2014-02-01

    Full Text Available There are currently many devices and techniques to quantify trace elements (TEs in various matrices, but their efficacy is dependent on the digestion methods (DMs employed in the opening of such matrices which, although "organic", present inorganic components which are difficult to solubilize. This study was carried out to evaluate the recovery of Fe, Zn, Cr, Ni, Cd and Pb contents in samples of composts and cattle, horse, chicken, quail, and swine manures, as well as in sewage sludges and peat. The DMs employed were acid digestion in microwaves with HNO3 (EPA 3051A; nitric-perchloric digestion with HNO3 + HClO4 in a digestion block (NP; dry ashing in a muffle furnace and solubilization of residual ash in nitric acid (MDA; digestion by using aqua regia solution (HCl:HNO3 in the digestion block (AR; and acid digestion with HCl and HNO3 + H2O2 (EPA 3050. The dry ashing method led to the greatest recovery of Cd in organic residues, but the EPA 3050 protocol can be an alternative method for the same purpose. The dry ashing should not be employed to determine the concentration of Cr, Fe, Ni, Pb and Zn in the residues. Higher Cr and Fe contents are recovered when NP and EPA 3050 are employed in the opening of organic matrices. For most of the residues analyzed, AR is the most effective method for recovering Ni. Microwave-assisted digestion methods (EPA3051 and 3050 led to the highest recovery of Pb. The choice of the DM that provides maximum recovery of Zn depends on the organic residue and trace element analyzed.

  5. Evaluation of residual stress distribution of butt-weld pipe and redistribution behavior with crack extension using neutron diffraction method

    International Nuclear Information System (INIS)

    Okido, Shinobu; Hayashi, Makoto; Minakawa, Nobuaki; Morii, Yukio; Ando, Kotoji

    2005-01-01

    Residual stress is known to be redistributed as a result of crack extension. The neutron diffraction method was used to evaluate this residual stress redistribution, using a specimen consisting of a butt-weld-jointed pipe made of type-304 austenitic stainless steel (inner diameter φ=97.1 mm, thickness t=8.9mm). Half-elliptical cracks were introduced by an electrical discharge machining at the inner surface of a heat-affected zone. The ratios of a/t, for crack depth a and specimen thickness t, were 0.25 and 0.5, with aspect ratios a/c, for crack half-length c, of 0.1 and 0.5 Comparing the residual stress distribution before and after the crack introduction showed that although the residual stress distribution along the line of the ligament at the deepest point of the crack changed slightly in front of the crack tip, it did not change throughout the ligament. This result shows that residual stress redistributes through-out in the whole crack tip region, including the width of the crack. (author)

  6. Diffraction grating strain gauge method: error analysis and its application for the residual stress measurement in thermal barrier coatings

    Science.gov (United States)

    Yin, Yuanjie; Fan, Bozhao; He, Wei; Dai, Xianglu; Guo, Baoqiao; Xie, Huimin

    2018-03-01

    Diffraction grating strain gauge (DGSG) is an optical strain measurement method. Based on this method, a six-spot diffraction grating strain gauge (S-DGSG) system has been developed with the advantages of high and adjustable sensitivity, compact structure, and non-contact measurement. In this study, this system is applied for the residual stress measurement in thermal barrier coatings (TBCs) combining the hole-drilling method. During the experiment, the specimen’s location is supposed to be reset accurately before and after the hole-drilling, however, it is found that the rigid body displacements from the resetting process could seriously influence the measurement accuracy. In order to understand and eliminate the effects from the rigid body displacements, such as the three-dimensional (3D) rotations and the out-of-plane displacement of the grating, the measurement error of this system is systematically analyzed, and an optimized method is proposed. Moreover, a numerical experiment and a verified tensile test are conducted, and the results verify the applicability of this optimized method successfully. Finally, combining this optimized method, a residual stress measurement experiment is conducted, and the results show that this method can be applied to measure the residual stress in TBCs.

  7. Efficient stabilization and acceleration of numerical simulation of fluid flows by residual recombination

    Science.gov (United States)

    Citro, V.; Luchini, P.; Giannetti, F.; Auteri, F.

    2017-09-01

    The study of the stability of a dynamical system described by a set of partial differential equations (PDEs) requires the computation of unstable states as the control parameter exceeds its critical threshold. Unfortunately, the discretization of the governing equations, especially for fluid dynamic applications, often leads to very large discrete systems. As a consequence, matrix based methods, like for example the Newton-Raphson algorithm coupled with a direct inversion of the Jacobian matrix, lead to computational costs too large in terms of both memory and execution time. We present a novel iterative algorithm, inspired by Krylov-subspace methods, which is able to compute unstable steady states and/or accelerate the convergence to stable configurations. Our new algorithm is based on the minimization of the residual norm at each iteration step with a projection basis updated at each iteration rather than at periodic restarts like in the classical GMRES method. The algorithm is able to stabilize any dynamical system without increasing the computational time of the original numerical procedure used to solve the governing equations. Moreover, it can be easily inserted into a pre-existing relaxation (integration) procedure with a call to a single black-box subroutine. The procedure is discussed for problems of different sizes, ranging from a small two-dimensional system to a large three-dimensional problem involving the Navier-Stokes equations. We show that the proposed algorithm is able to improve the convergence of existing iterative schemes. In particular, the procedure is applied to the subcritical flow inside a lid-driven cavity. We also discuss the application of Boostconv to compute the unstable steady flow past a fixed circular cylinder (2D) and boundary-layer flow over a hemispherical roughness element (3D) for supercritical values of the Reynolds number. We show that Boostconv can be used effectively with any spatial discretization, be it a finite

  8. Analysis of residual stresses on the transverse beam of a casting stand by means of drilling method

    Directory of Open Access Journals (Sweden)

    P. Frankovský

    2014-10-01

    Full Text Available The presented paper demonstrates the application of drilling method in the analysis of residual stresses on the transverse beam of a casting stand. In the initial stage of the analysis the determination of strains was done for individual steps of drilling in the area which was determined by means of numerical analysis. The drilling was carried out gradually by 0,5 mm up to the depth of 5 mm, while the diameter of the drilled hole was 3,2 mm. During the analysis we used the drilling device RS-200, strain indicator P3 and SGD 1-RY21-3/120. The paper presents the development of residual stresses throughout the depth of the drilled hole which were determined according to standard ASTM E837-01, by means of integral method, power series method and by means of Power Series method.

  9. Evaluation of chloramphenicol residues in poultry meat using ELISA method in Isfahan

    Directory of Open Access Journals (Sweden)

    E Rahimi

    2008-11-01

    Full Text Available Chloramphenicol is classified as a broad spectrum veterinary drugs used to treat pulmonary infections in the poultry industry. Even relatively low levels of chloramphenicol residues may give rice to an irreversible type of bone marrow depression leading eventually to anaplastic anemia. This study was conducted with the aim of chicken meat. Chloramphenicol concentraction was measured by enzyme (ELISA in 140 chicken meat samples (thigh muscles presented to the consumption market of isfahan city. In 25 of the 140 evaluated samples (17.9%, presence of chloramephnicol residues was detected in concentrations rouging form 14 to 311 ng/kg with a mean ±standard deviation of 97.9 ±17.7 ng/kg. the results of chloramphenicol residues were low in the samples but this drug is still being used in the poultry industry and this can be a risk to public health.

  10. Evaluation of the antibacterial residue surveillance programme in Danish pigs using Bayesian methods

    DEFF Research Database (Denmark)

    Freitas de Matos Baptista, Filipa; Alban, L.; Olsen, A. M.

    2012-01-01

    the impact of a potential risk-based sampling approach to the residue surveillance programme in Danish slaughter pigs. Danish surveillance data from 2005 to 2009 and limited knowledge about true prevalence and test sensitivity and specificity were included in the model. According to the model, the true...... classes used in Danish pigs. If high-risk slaughter pigs could be identified by taking into account antibacterial use or meat inspection risk factors, a potential risk-based sampling approach to antibacterial residue surveillance in slaughter pigs would allow reducing the sample size substantially, while...... antibacterial residue prevalence in Danish pigs is very low in both sows (~0.20%) and slaughter pigs (~0.01%). Despite data constraints, the results suggest that the current screening test used in Denmark presents high sensitivity (85-99%) and very high specificity (>99%) for the most relevant antibacterial...

  11. Residual Stress Distribution In Heat Affected Zone Of Welded Steel By Means Of Neutron Diffraction Method

    International Nuclear Information System (INIS)

    Fajar, Andika; Prasuad; Gunawan; Muslich, M. Rifai

    1996-01-01

    Three dimensional residual stress distribution in the heat affected zone of 10 mm thick welded steel by means of neutron diffraction technique has been measured. The results showed that the residual stress was distributed near the welded metal, namely within about 46,25 mm. The major tensile stresses occurred in the X-direction, and they attained a level greater than 2000 MPa through the position far away fram the weld. The tensile stresses in the Y and Z- directions lied between 500 and 1500 MPa, The results also suggest that the stress in the surface was greater than that in the middle of the sample

  12. HemeBIND: a novel method for heme binding residue prediction by combining structural and sequence information

    Directory of Open Access Journals (Sweden)

    Hu Jianjun

    2011-05-01

    Full Text Available Abstract Background Accurate prediction of binding residues involved in the interactions between proteins and small ligands is one of the major challenges in structural bioinformatics. Heme is an essential and commonly used ligand that plays critical roles in electron transfer, catalysis, signal transduction and gene expression. Although much effort has been devoted to the development of various generic algorithms for ligand binding site prediction over the last decade, no algorithm has been specifically designed to complement experimental techniques for identification of heme binding residues. Consequently, an urgent need is to develop a computational method for recognizing these important residues. Results Here we introduced an efficient algorithm HemeBIND for predicting heme binding residues by integrating structural and sequence information. We systematically investigated the characteristics of binding interfaces based on a non-redundant dataset of heme-protein complexes. It was found that several sequence and structural attributes such as evolutionary conservation, solvent accessibility, depth and protrusion clearly illustrate the differences between heme binding and non-binding residues. These features can then be separately used or combined to build the structure-based classifiers using support vector machine (SVM. The results showed that the information contained in these features is largely complementary and their combination achieved the best performance. To further improve the performance, an attempt has been made to develop a post-processing procedure to reduce the number of false positives. In addition, we built a sequence-based classifier based on SVM and sequence profile as an alternative when only sequence information can be used. Finally, we employed a voting method to combine the outputs of structure-based and sequence-based classifiers, which demonstrated remarkably better performance than the individual classifier alone

  13. Characterization of micro-scale residual stress around thermal grown oxide using micro-slotting method and geometric phase analysis

    Science.gov (United States)

    Zhang, Q.; Xie, H.; Liu, Z.; Dai, X.

    2018-03-01

    Characterization of residual stress around thermal grown oxide (TGO) is important for understanding the spallation failure of thermal barrier coatings (TBCs). Cr3+ photoluminescence piezo-spectroscopy (CPLPS) is a nondestructive method for measuring the in-plane residual stress in the TGO layer. However, using CPLPS it is hard to evaluate the out-of-plane residual stress around TGO. Here, we adopted the micro-slotting method combined with geometric phase analysis (GPA) for measuring the in-plane and out-of-plane stresses around TGO, with measured areas of 6  ×  4 µm2. In the experiment, a grating and a slot were milled on the specimen surface using focused ion beam, and GPA was applied to analyze the grating structure before and after the slot milling for calculating the released displacement field. Then finite element analysis was used to infer the residual stress in the direction vertical to the micro-slot. Two experiments were performed on the in-service TBC specimen. The first experiment presented the in-plane compression in the TGO, while the second experiment presented the out-of-plane tension at the crest of the TGO/BC interface, thus validating the theoretical analysis.

  14. REST: a computer system for estimating logging residue by using the line-intersect method

    Science.gov (United States)

    A. Jeff Martin

    1975-01-01

    A computer program was designed to accept logging-residue measurements obtained by line-intersect sampling and transform them into summaries useful for the land manager. The features of the program, along with inputs and outputs, are briefly described, with a note on machine compatibility.

  15. An EThcD-Based Method for Discrimination of Leucine and Isoleucine Residues in Tryptic Peptides

    Science.gov (United States)

    Zhokhov, Sergey S.; Kovalyov, Sergey V.; Samgina, Tatiana Yu.; Lebedev, Albert T.

    2017-08-01

    An EThcD-based approach for the reliable discrimination of isomeric leucine and isoleucine residues in peptide de novo sequencing procedure has been proposed. A multistage fragmentation of peptide ions was performed with Orbitrap Elite mass spectrometer in electrospray ionization mode. At the first stage, z-ions were produced by ETD or ETcaD fragmentation of doubly or triply charged peptide precursor ions. These primary ions were further fragmented by HCD with broad-band ion isolation, and the resulting w-ions showed different mass for leucine and isoleucine residues. The procedure did not require manual isolation of specific z-ions prior to HCD stage. Forty-three tryptic peptides (3 to 27 residues) obtained by trypsinolysis of human serum albumin (HSA) and gp188 protein were analyzed. To demonstrate a proper solution for radical site migration problem, three non-tryptic peptides were also analyzed. A total of 93 leucine and isoleucine residues were considered and 83 of them were correctly identified. The developed approach can be a reasonable substitution for additional Edman degradation procedure, which is still used in peptide sequencing for leucine and isoleucine discrimination.

  16. METHODOLOGY OF ESTABLISHING RESIDUAL LIFETIME OF LIFTING INSTALATION BY NON-DESTRUCTIVE METHODS

    Directory of Open Access Journals (Sweden)

    Florin VÎLCEANU

    2013-05-01

    Full Text Available In this paper are presented first the theoretical ground for metal fatigue and then analysissteps to be taken in order to establishing the residual lifetime of a lifting crane by non-destructivemethods, while observing all the current regulations

  17. Simulation of 3D parachute fluid–structure interaction based on nonlinear finite element method and preconditioning finite volume method

    Directory of Open Access Journals (Sweden)

    Fan Yuxin

    2014-12-01

    Full Text Available A fluid–structure interaction method combining a nonlinear finite element algorithm with a preconditioning finite volume method is proposed in this paper to simulate parachute transient dynamics. This method uses a three-dimensional membrane–cable fabric model to represent a parachute system at a highly folded configuration. The large shape change during parachute inflation is computed by the nonlinear Newton–Raphson iteration and the linear system equation is solved by the generalized minimal residual (GMRES method. A membrane wrinkling algorithm is also utilized to evaluate the special uniaxial tension state of membrane elements on the parachute canopy. In order to avoid large time expenses during structural nonlinear iteration, the implicit Hilber–Hughes–Taylor (HHT time integration method is employed. For the fluid dynamic simulations, the Roe and HLLC (Harten–Lax–van Leer contact scheme has been modified and extended to compute flow problems at all speeds. The lower–upper symmetric Gauss–Seidel (LU-SGS approximate factorization is applied to accelerate the numerical convergence speed. Finally, the test model of a highly folded C-9 parachute is simulated at a prescribed speed and the results show similar characteristics compared with experimental results and previous literature.

  18. An Innovative Rapid Method for Analysis of 10 Organophosphorus Pesticide Residues in Wheat by HS-SPME-GC-FPD/MSD.

    Science.gov (United States)

    Du, Xin; Ren, YongLin; Beckett, Stephen J

    2016-01-01

    The rapid detection of pesticide residues in wheat has become a top food security priority. A solvent-free headspace solid-phase microextraction (HS-SPME) has been evaluated for rapid screening of organophosphorus pesticide (OPP) residues in wheat with high sensitivity. Individual wheat samples (1.7 g), spiked with 10 OPPs, were placed in a 4 mL sealed amber glass vial and heated at 60°C for 45 min. During this time, the OPP residues were extracted with a 50 μm/30 μm divinylbenzene (DVB)/carboxen (CAR)/plasma desorption mass spectroscopy polydimethylsiloxane (PDMS) fiber from the headspace above the sample. The fiber was then removed and injected into the GC injection port at 250°C for desorption of the extracted chemicals. The multiple residues were identified by a GC mass spectrometer detector (GC-MSD) and quantified with a GC flame photometric detector (GC-FPD). Seven spiked levels of 10 OPPs on wheat were analyzed. The GC responses for a 50 μm/30 μm DVB/CAR/PDMS fiber increased with increasing spiking levels, yielding significant (R(2) > 0.98) linear regressions. The lowest LODs of the multiple pesticide standards were evaluated under the conditions of the validation study in a range of levels from 0 (control) to 100 ng of pesticide residue per g of wheat that separated on a low-polar GC capillary column (Agilent DB-35UI). The results of the HS-SPME method were compared with the QuEChERS AOAC 2007.01 method and they showed several advantages over the latter. These included improved sensitivity, selectivity, and simplicity.

  19. Using sparse LU factorisation to precondition GMRES for a family of similarly structured matrices arising from process modelling

    Energy Technology Data Exchange (ETDEWEB)

    Brooking, C. [Univ. of Bath (United Kingdom)

    1996-12-31

    Process engineering software is used to simulate the operation of large chemical plants. Such simulations are used for a variety of tasks, including operator training. For the software to be of practical use for this, dynamic simulations need to run in real-time. The models that the simulation is based upon are written in terms of Differential Algebraic Equations (DAE`s). In the numerical time-integration of systems of DAE`s using an implicit method such as backward Euler, the solution of nonlinear systems is required at each integration point. When solved using Newton`s method, this leads to the repeated solution of nonsymmetric sparse linear systems. These systems range in size from 500 to 20,000 variables. A typical integration may require around 3000 timesteps, and if 4 Newton iterates were needed on each time step, then this means approximately 12,000 linear systems must be solved. The matrices produced by the simulations have a similar sparsity pattern throughout the integration. They are also severely ill-conditioned, and have widely-scattered spectra.

  20. Two-Dimensional UV Absorption Correlation Spectroscopy as a Method for the Detection of Thiamethoxam Residue in Tea

    Science.gov (United States)

    Zhang, J.; Zhao, Zh.; Wang, L.; Zhu, X.; Shen, L.; Yu, Y.

    2015-05-01

    Two-dimensional correlation spectroscopy (2D-COS) combined with UV absorption spectroscopy was evaluated as a technique for the identification of spectral regions associated with the residues of thiamethoxam in tea. There is only one absorption peak at 275 nm in the absorption spectrum of a mixture of thiamethoxam and tea, which is the absorption peak of tea. Based on 2D-COS, the absorption peak of thiamethoxam at 250 nm is extracted from the UV spectra of the mixture. To determine the residue of thiamethoxam in tea, 250 nm is selected as the measured wavelength, at which the fitting result is as follows: the residual sum of squares is 0.01375, standard deviation R2 is 0.99068, and F value is 426. Statistical analysis shows that there is a significant linear relationship between the concentration of thiamethoxam in tea and the absorbance at 250 nm in the UV spectra of the mixture. Moreover, the average prediction error is 0.0033 and the prediction variance is 0.1654, indicating good predictive result. Thus, the UV absorption spectrum can be used as a measurement method for rapid detection of thiamethoxam residues in tea.

  1. Method for improve x-ray diffraction determinations of residual stress in nickel-base alloys

    Science.gov (United States)

    Berman, Robert M.; Cohen, Isadore

    1990-01-01

    A process for improving the technique of measuring residual stress by x-ray diffraction in pieces of nickel-base alloys which comprises covering part of a predetermined area of the surface of a nickel-base alloy with a dispersion, exposing the covered and uncovered portions of the surface of the alloy to x-rays by way of an x-ray diffractometry apparatus, making x-ray diffraction determinations of the exposed surface, and measuring the residual stress in the alloy based on these determinations. The dispersion is opaque to x-rays and serves a dual purpose since it masks off unsatisfactory signals such that only a small portion of the surface is measured, and it supplies an internal standard by providing diffractogram peaks comparable to the peaks of the nickel alloy so that the alloy peaks can be very accurately located regardless of any sources of error external to the sample.

  2. Method for improving x-ray diffraction determinations of residual stress in nickel-base alloys

    Science.gov (United States)

    Berman, R.M.; Cohen, I.

    1988-04-26

    A process for improving the technique of measuring residual stress by x-ray diffraction in pieces of nickel-base alloys is discussed. Part of a predetermined area of the surface of a nickel-base alloy is covered with a dispersion. This exposes the covered and uncovered portions of the surface of the alloy to x-rays by way of an x-ray diffractometry apparatus, making x-ray diffraction determinations of the exposed surface, and measuring the residual stress in the alloy based on these determinations. The dispersion is opaque to x-rays and serves a dual purpose, since it masks off unsatisfactory signals such that only a small portion of the surface is measured, and it supplies an internal standard by providing diffractogram peaks comparable to the peaks of the nickel alloy so that the alloy peaks can be very accurately located regardless of any sources of error external to the sample. 2 figs.

  3. STAGS Developments for Residual Strength Analysis Methods for Metallic Fuselage Structures

    Science.gov (United States)

    Young, Richard D.; Rose, Cheryl A.

    2014-01-01

    A summary of advances in the Structural Analysis of General Shells (STAGS) finite element code for the residual strength analysis of metallic fuselage structures, that were realized through collaboration between the structures group at NASA Langley, and Dr. Charles Rankin is presented. The majority of the advancements described were made in the 1990's under the NASA Airframe Structural Integrity Program (NASIP). Example results from studies that were conducted using the STAGS code to develop improved understanding of the nonlinear response of cracked fuselage structures subjected to combined loads are presented. An integrated residual strength analysis methodology for metallic structure that models crack growth to predict the effect of cracks on structural integrity is demonstrated

  4. Acoustic transmission in non-uniform ducts with mean flow. I - The method of weighted residuals. II - The finite element method

    Science.gov (United States)

    Eversman, W.; Astley, R. J.

    1981-01-01

    The problem of acoustic transmission through nonuniform ducts containing a high-speed subsonic flow is studied by means of the method of weighted residuals in the form of a modified Galerkin method and a Galerkin formulation of the finite element method. The method of weighted residuals is shown to employ the basis functions generated from eigenvalue calculations for the case of no flow, and is verified by comparison with exact eigenvalue calculations in the uniform duct case and numerical solutions of the one-dimensional form of the equations in the nonuniform duct case. The finite element scheme based on both the Galerkin method and the residual least squares method and employing eight-noded isoparametric elements is presented and used to investigate multimodal propagation by the coupling of the solution in the duct nonuniform section to modal expansions in uniform sections. Comparison of the results of the two methods reveals them to be in substantial agreement, and predicts the importance of multimodal interactions at high Mach numbers.

  5. On Line Current Monitoring and Application of a Residual Method for Eccentricity Fault Detection

    Directory of Open Access Journals (Sweden)

    METATLA, A.

    2011-02-01

    Full Text Available This work concerns the monitoring and diagnosis of faults in induction motors. We develop an approach based on residual analysis of stator currents to detect and diagnose faults eccentricity static, dynamic and mixed in three phase induction motor. To simulate the behavior of motor failure, a model is proposed based on the approach of magnetically coupled coils. The simulation results show the importance of the approach applied for the detection and diagnosis of fault in three phase induction motor.

  6. Development of Analytical Method and Monitoring of Veterinary Drug Residues in Korean Animal Products.

    Science.gov (United States)

    Song, Jae-Sang; Park, Su-Jeong; Choi, Jung-Yun; Kim, Jin-Sook; Kang, Myung-Hee; Choi, Bo-Kyung; Hur, Sun Jin

    2016-01-01

    This study was conducted to determine the residual amount of veterinary drugs such as meloxicam, flunixin, and tulathromycin in animal products (beef, pork, horsemeat, and milk). Veterinary drugs have been widely used in the rearing of livestock to prevent and treat diseases. A total of 152 samples were purchased from markets located in major Korean cities (Seoul, Busan, Incheon, Daegu, Daejeon, Gwangju, Ulsan and Jeju), including Jeju. Veterinary drugs were analyzed by liquid chromatography-tandem mass spectrometry according to the Korean Food Standards Code. The resulting data, which are located within 70-120% of recovery range and less than 20% of relative standard deviations, are in compliance with the criteria of CODEX. A total of five veterinary drugs were detected in 152 samples, giving a detection rate of approximately 3.3%; and no food source violated the guideline values. Our result indicated that most of the veterinary drug residues in animal products were below the maximum residue limits specified in Korea.

  7. A direct qPCR method for residual DNA quantification in monoclonal antibody drugs produced in CHO cells.

    Science.gov (United States)

    Hussain, Musaddeq

    2015-11-10

    Chinese hamster ovary (CHO) cells are the host cell of choice for manufacturing of monoclonal antibody (mAb) drugs in the biopharmaceutical industry. Host cell DNA is an impurity of such manufacturing process and must be controlled and monitored in order to ensure drug purity and safety. A conventional method for quantification of host residual DNA in drug requires extraction of DNA from the mAb drug substance with subsequent quantification of the extracted DNA using real-time PCR (qPCR). Here we report a method where the DNA extraction step is eliminated prior to qPCR. In this method, which we have named 'direct resDNA qPCR', the mAb drug substance is digested with a protease called KAPA in a 96-well PCR plate, the protease in the digest is then denatured at high temperature, qPCR reagents are added to the resultant reaction wells in the plate along with standards and controls in other wells of the same plate, and the plate subjected to qPCR for analysis of residual host DNA in the samples. This direct resDNA qPCR method for CHO is sensitive to 5.0fg of DNA with high precision and accuracy and has a wide linear range of determination. The method has been successfully tested with four mAbs drug, two IgG1 and two IgG4. Both the purified drug substance as well as a number of process intermediate samples, e.g., bioreactor harvest, Protein A column eluate and ion-exchange column eluates were tested. This method simplifies the residual DNA quantification protocol, reduces time of analysis and leads to increased assay sensitivity and development of automated high-throughput methods. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Rapid ion-pair liquid chromatographic method for the determination of fenbendazole marker residue in fermented dairy products.

    Science.gov (United States)

    Vousdouka, Venetia I; Papapanagiotou, Elias P; Angelidis, Apostolos S; Fletouris, Dimitrios J

    2017-04-15

    A simple, rapid and sensitive liquid chromatographic method that allows for the quantitative determination of fenbendazole residues in fermented dairy products is described. Samples were extracted with a mixture of acetonitrile-phosphoric acid and the extracts were defatted with hexane to be further partitioned into ethyl acetate. The organic layer was evaporated to dryness and the residue was reconstituted in mobile phase. Separation of fenbendazole and its sulphoxide, sulphone, and p-hydroxylated metabolites was carried out isocratically with a mobile phase containing both positively and negatively charged pairing ions. Overall recoveries ranged from 79.8 to 88.8%, while precision data, based on within and between days variations, suggested an overall relative standard deviation of 6.3-11.0%. The detection and quantification limits were lower than 9 and 21μg/kg, respectively. The method has been successfully applied to quantitate fenbendazole residues in Feta cheese and yoghurt made from spiked and incurred ovine milk. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Effects of Adopting Different Kinds of Collecting Method for Years on Film Residual Coefficient and Maize Yields

    OpenAIRE

    TANG Wen-xue; MA Zhong-ming; WEI Tao

    2017-01-01

    Wide usage of mulching technology has increased crop yields, but the large amounts of mulching film residue resulting from widespread use of plastic film in China has brought about a series of pollution hazards. Based on a 4-year (2011-2014) long-term experiment, the effects of different kinds of collecting mothod (zero plastic film residues, conventional plastic film residues, whole plastic film residues remainded) on plastic film residues, residual coefficient and maize yield were explored....

  10. Gas Chromatographic Method: Tool for Rapid and Sensitive Analysis of Residual Solvents in Amoxicillin and Ampicillin Tablets

    Directory of Open Access Journals (Sweden)

    Sk Manirul Haque

    2015-12-01

    Full Text Available A simple and sensitive static head space gas chromatographic (SH-GC method equipped with FID has been developed and validated for simultaneous determination of residual solvents e.g.,  methanol, dichloromethane and toluene in two therapeutic drugs such as amoxicillin  and ampicillin. The separation was achieved with 30 m long Elite - 5 fused silica capillary column and 0.32 mm inner diameter. The developed SH-GC method offered symmetric peak shape, good resolution and reasonable retention time for all the solvents. Beer’s law was obeyed in the concentration ranges 100 – 1200, 50 – 1000 and 50 – 500 ppm for methanol, dichloromethane and toluene, respectively. The method was validated according to international conference on harmonization (ICH guidelines in terms of specificity, linearity, precision, accuracy, limit of detection, limit of quantitation, robustness and solution stability. The degrees of linearity of the calibration curves, the percent recoveries, relative standard deviation for the method were also determined. All the validation parameters were within the acceptable range. The developed SH-GC method could, therefore, be suitable for simple and rapid detection of trace levels residual solvents in other pharmaceutical products and thereby it could be used for routine analysis in any analytical laboratory.

  11. Residual deposits (residual soil)

    International Nuclear Information System (INIS)

    Khasanov, A.Kh.

    1988-01-01

    Residual soil deposits is accumulation of new formate ore minerals on the earth surface, arise as a result of chemical decomposition of rocks. As is well known, at the hyper genes zone under the influence of different factors (water, carbonic acid, organic acids, oxygen, microorganism activity) passes chemical weathering of rocks. Residual soil deposits forming depends from complex of geologic and climatic factors and also from composition and physical and chemical properties of initial rocks

  12. Preliminary results for the detection method of perfluoroalkyl substances (PFASs residues in pork

    Directory of Open Access Journals (Sweden)

    Shih-kuo Lin

    2017-05-01

    Full Text Available The perfluoroalkyl substances (PFASs residues, which come from environmental pollution, tend to accumulate in the food chain (EFSA, 2008; Guerranti et al., 2013. 17 chemicals of PFASs family were selected for this study. Fresh pork samples were extracted by Waters® WAX SPE (solid phase extraction cartridges. All extracted samples were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS. The results of calibration curves of each PFAS were good, the R2 values ranging from 0.9901 to 0.9993. The Recoveries were in the range 80%-119%. The protocol of extraction by Waters® WAX SPE cartridge will be applied in future studies.

  13. Development of Analytical Method for Predicting Residual Mechanical Properties of Corroded Steel Plates

    Directory of Open Access Journals (Sweden)

    J. M. R. S. Appuhamy

    2011-01-01

    Full Text Available Bridge infrastructure maintenance and assurance of adequate safety is of paramount importance in transportation engineering and maintenance management industry. Corrosion causes strength deterioration, leading to impairment of its operation and progressive weakening of the structure. Since the actual corroded surfaces are different from each other, only experimental approach is not enough to estimate the remaining strength of corroded members. However, in modern practices, numerical simulation is being used to replace the time-consuming and expensive experimental work and to comprehend on the lack of knowledge on mechanical behavior, stress distribution, ultimate behavior, and so on. This paper presents the nonlinear FEM analyses results of many corroded steel plates and compares them with their respective tensile coupon tests. Further, the feasibility of establishing an accurate analytical methodology to predict the residual strength capacities of a corroded steel member with lesser number of measuring points is also discussed.

  14. Effects of Adopting Different Kinds of Collecting Method for Years on Film Residual Coefficient and Maize Yields

    Directory of Open Access Journals (Sweden)

    TANG Wen-xue

    2017-03-01

    Full Text Available Wide usage of mulching technology has increased crop yields, but the large amounts of mulching film residue resulting from widespread use of plastic film in China has brought about a series of pollution hazards. Based on a 4-year (2011-2014 long-term experiment, the effects of different kinds of collecting mothod (zero plastic film residues, conventional plastic film residues, whole plastic film residues remainded on plastic film residues, residual coefficient and maize yield were explored. Plastic film residues mainly remained in 0~10 cm, 10~20 cm soil layers. In 0~30 cm soil layers, the two types of mulch residues (>25 cm2, 4~25 cm2 under zero plastic film residues treatment were much less than conventional plastic film residues and whole plastic film residues remainded treatments, no significant differences were observed in the mulch residues (2 among 3 treatments. After maize harvest, the amount of plastic film residues under zero plastic film residues, conventional plastic film residues and whole plastic film residues remainded treatments were 52.71, 80.85 kg·hm-2 and 152.65 kg·hm-2, respectively, the residual coefficient for zero plastic film residues, conventional plastic film residues and whole plastic film residues remainded treatments were -9.45%, 8.53% and 54.42%, respectively. The stem diameter, ear length, ear width, ear row number, grain number per row and 100-grain weight of maize decreased with the increase of residual film amount. Compared with the conventional plastic film residues, the mean grain yield of whole plastic film residues remainded treatment decreased by 15.08%, whereas the zero plastic film residues treatment increased by 4.70%. The plastic film residues, residual coefficient and maize yield were comprehensively analyzed, the conventional plastic film residues practice should be adopted currently without appropriate plastic film residues collector. But from the long-term development, we should speed up the

  15. SequenceCEROSENE: a computational method and web server to visualize spatial residue neighborhoods at the sequence level.

    Science.gov (United States)

    Heinke, Florian; Bittrich, Sebastian; Kaiser, Florian; Labudde, Dirk

    2016-01-01

    To understand the molecular function of biopolymers, studying their structural characteristics is of central importance. Graphics programs are often utilized to conceive these properties, but with the increasing number of available structures in databases or structure models produced by automated modeling frameworks this process requires assistance from tools that allow automated structure visualization. In this paper a web server and its underlying method for generating graphical sequence representations of molecular structures is presented. The method, called SequenceCEROSENE (color encoding of residues obtained by spatial neighborhood embedding), retrieves the sequence of each amino acid or nucleotide chain in a given structure and produces a color coding for each residue based on three-dimensional structure information. From this, color-highlighted sequences are obtained, where residue coloring represent three-dimensional residue locations in the structure. This color encoding thus provides a one-dimensional representation, from which spatial interactions, proximity and relations between residues or entire chains can be deduced quickly and solely from color similarity. Furthermore, additional heteroatoms and chemical compounds bound to the structure, like ligands or coenzymes, are processed and reported as well. To provide free access to SequenceCEROSENE, a web server has been implemented that allows generating color codings for structures deposited in the Protein Data Bank or structure models uploaded by the user. Besides retrieving visualizations in popular graphic formats, underlying raw data can be downloaded as well. In addition, the server provides user interactivity with generated visualizations and the three-dimensional structure in question. Color encoded sequences generated by SequenceCEROSENE can aid to quickly perceive the general characteristics of a structure of interest (or entire sets of complexes), thus supporting the researcher in the initial

  16. Triaxial X-Ray Diffraction Method and its Application to Monitor Residual Stress in Surface Layers after High-Feed Milling

    Science.gov (United States)

    Zaušková, Lucia; Czán, Andrej; Šajgalík, Michal; Pobijak, Jozef; Mikloš, Matej

    2017-10-01

    High-feed milling is a milling method characteristic with shallow depth of cut and high feed rate to maximize the amount of removed metal from a part, generating residual stresses in the surface and subsurface layers of the machined parts. The residual stress has a large influence on the functional properties of the components. The article is focused on the application of triaxial x-ray diffraction method to monitor residual stresses after high feed milling. Significance of triaxial measuring method is the capability of measuring in different angles so it is possible to acquire stress tensor containing normal and shear stress components.

  17. Pesticide residues in fruit samples: comparison of different QuEChERS methods using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Christia, C; Bizani, E; Christophoridis, C; Fytianos, K

    2015-09-01

    Acetate- and citrate-buffered quick, easy, cheap, effective, rugged, safe (QuEChERS) pretreatment methods were evaluated for the determination of various pesticides in peaches, grapes, apples, bananas, pears, and strawberries from various regions of Greece, using LC-MS/MS. The purposes of this study were (i) to evaluate which type of QuEChERS method was the most appropriate and effective for each matrix; (ii) to apply the selected QuEChERS method for each matrix, in order to detect and quantify pesticide residues in various fruit samples using UPLC-MS/MS; (iii) to examine the concentration distribution of pesticide classes among fruit originating from various areas; and (iv) to assess pesticide concentration distribution between peel and flesh of fruit in order to evaluate the penetration of pesticide residues in the fruit flesh. Acetate-buffered QuEChERS was found to be the most suitable technique for most of the fruit matrices. According to the recovery values at two different concentration levels, peaches should preferably be treated by the citrate-buffered type, whereas grapes, bananas, apples, pears, and strawberries are best treated by the acetate-buffered version, although the differences in efficiency were small. The addition of graphitized carbon black significantly decreases the recovery of specific pesticides in all matrices except for strawberries. The majority of values do not exceed the official maximum residue levels set by the European Commission. Organophosphates proved to be the most commonly detected category along with triazines-triazoles-conazoles group and by carbamates. Apples and pears seem to be the most contaminated fruit matrices among those tested. Distribution of pesticide classes shows variations between different regions, suggesting different pesticide application practices. In the case of peaches and pears, there is an equal distribution of detected pesticides between peel and flesh, indicating penetration of contaminants into the

  18. Reported prevalence and quantitative LC-MS methods for the analysis of veterinary drug residues in honey: a review.

    Science.gov (United States)

    Venable, Ryan; Haynes, Carion; Cook, Jo Marie

    2014-04-01

    Insect pollination increases the value and productivity of three-quarters of crop species grown for food. Declining beehive health in commercial apiaries has resulted in numerous reports from government laboratories worldwide of contamination with antimicrobial chemicals in honey. This review includes pertinent discussion of legislation and events leading to increased government oversight in the commercial honey market. A detailed summary of the variety and prevalence of veterinary drug residues being found in honey as well as a selection of robust quantitative and confirmatory LC-MS methods with an emphasis on those adopted by government testing laboratories are presented.

  19. Validation of a method for determination of amoxicillin residues applied to cleaning validation process in penicillins pharmaceutical industry

    OpenAIRE

    Gomes, Maria Luiza Pinheiro Costa; Souza, Scheilla Vitorino Carvalho de

    2010-01-01

    The aim of this work was the single-laboratory validation of a quantitative method for the determination of amoxicillin residues in support of cleaning control and validation. Linearity was demonstrated between 2.5 and 17.5 μg/mL, without matrix effects. Mean recoveries ranged from 84.00 to 103.74% and the relative standard deviation under repetitivity and within-reproducibility conditions were from 0.58 to 4.20% and from 0.79 to 4.39%, respectively. The theoretical limits of detection a...

  20. A Matching Method of Space-borne Laser Altimeter Big Footprint Waveform and Terrain Based on Cross Cumulative Residual Entropy

    Directory of Open Access Journals (Sweden)

    YUE Chunyu

    2017-03-01

    Full Text Available A matching method of space-borne laser altimeter big footprint waveform and terrain based on cross cumulative residual entropy(CCRE is proposed. Firstly, the waveform data and digital surface model(DSM data are projected to the statistics domain, according to the terrain structure information of the waveform, where statistics signal vectors of the two data are in the same dimension. Then, the waveform data and DSM image are matched in the statistics domain with CCRE. Experiments show that the algorithm proposed is effective in waveform and terrain matching, and the matching accuracy is within 1 pixel.

  1. Standard test method for verifying the alignment of X-Ray diffraction instrumentation for residual stress measurement

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the preparation and use of a flat stress-free test specimen for the purpose of checking the systematic error caused by instrument misalignment or sample positioning in X-ray diffraction residual stress measurement, or both. 1.2 This test method is applicable to apparatus intended for X-ray diffraction macroscopic residual stress measurement in polycrystalline samples employing measurement of a diffraction peak position in the high-back reflection region, and in which the θ, 2θ, and ψ rotation axes can be made to coincide (see Fig. 1). 1.3 This test method describes the use of iron powder which has been investigated in round-robin studies for the purpose of verifying the alignment of instrumentation intended for stress measurement in ferritic or martensitic steels. To verify instrument alignment prior to stress measurement in other metallic alloys and ceramics, powder having the same or lower diffraction angle as the material to be measured should be prepared in similar fashion...

  2. Analytical quality assurance in veterinary drug residue analysis methods: matrix effects determination and monitoring for sulfonamides analysis.

    Science.gov (United States)

    Hoff, Rodrigo Barcellos; Rübensam, Gabriel; Jank, Louise; Barreto, Fabiano; Peralba, Maria do Carmo Ruaro; Pizzolato, Tânia Mara; Silvia Díaz-Cruz, M; Barceló, Damià

    2015-01-01

    In residue analysis of veterinary drugs in foodstuff, matrix effects are one of the most critical points. This work present a discuss considering approaches used to estimate, minimize and monitoring matrix effects in bioanalytical methods. Qualitative and quantitative methods for estimation of matrix effects such as post-column infusion, slopes ratios analysis, calibration curves (mathematical and statistical analysis) and control chart monitoring are discussed using real data. Matrix effects varying in a wide range depending of the analyte and the sample preparation method: pressurized liquid extraction for liver samples show matrix effects from 15.5 to 59.2% while a ultrasound-assisted extraction provide values from 21.7 to 64.3%. The matrix influence was also evaluated: for sulfamethazine analysis, losses of signal were varying from -37 to -96% for fish and eggs, respectively. Advantages and drawbacks are also discussed considering a workflow for matrix effects assessment proposed and applied to real data from sulfonamides residues analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Residual damage in different ground logging methods alongside skid trails and winching strips

    Czech Academy of Sciences Publication Activity Database

    Aysan Badraghi, Naghimeg; Erler, J.; Hosseini, S. A. O.

    2015-01-01

    Roč. 61, č. 12 (2015), s. 526-534 ISSN 1212-4834 Institutional support: RVO:67179843 Keywords : Long-length method (LLM) * Short-length method (SLM) * Skidding and winching operations * Tree-length method (TLM) Subject RIV: EF - Botanics

  4. Mechanized methods for harvesting residual biomass from Mediterranean fruit tree cultivations

    Directory of Open Access Journals (Sweden)

    Borja Velázquez-Martí

    2012-06-01

    Full Text Available This study evaluates the technology and work systems used in order to harvest residual biomass from pruning in the specific conditions of Mediterranean fruit orchards (narrow distances between crop-rows. Harvesting has been divided into several types of operations - pruning, biomass alignment between crop tracks, biomass concentration in piles, chipping and bundling - which have been analyzed in five Mediterranean cultivations for three years. Altogether, three types of pruning have been analyzed: Manual, previous mechanical followed by manual, and fully mechanical; Two types of alignment: Manual and mechanical; Three concentration systems: Manual, tractor with a rake and a forwarder; Four chipping work organization systems: chipper driven inside orchard and manually fed by operators, mobile chipper driven inside orchard with pick-up header, mobile chipper fed by means of mechanical crane, chipper mounted on a truck fed by means of mechanical crane, which was working in a fixed position in a border of the plot after wood concentration. Also two bundling organization systems were checked: bundler machine working in a fixed position after wood concentration and working inside the plot driven among the crops. Previous concentration of the materials was the best alternative for their chipping or bundling in the studied conditions. Regression models have been calculated to predict the time of work of machinery and labor for each alternative. These equations were used to implement logistic planning as the Borvemar model, which defines a logistics network for supplying bio-energy systems.

  5. Validation of an efficient method for the determination of pesticide residues in fruits and vegetables using ethyl acetate for extraction.

    Science.gov (United States)

    Aysal, Perihan; Ambrus, Arpád; Lehotay, Steven J; Cannavan, Andrew

    2007-01-01

    In this study, a version of the "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) method was modified to use ethyl acetate (EtOAc) rather than acetonitrile (MeCN) for extraction in the determination of multiple pesticide residues in fruits and vegetables. EtOAc is better suited than MeCN for gas chromatographic (GC) analysis with electron capture detection (ECD) and nitrogen-phosphorus detection (NPD). The method entailed extraction of 30 g chopped sample plus 5 g NaHCO(3) and 30 g anhydrous Na(2)SO(4) with 60 mL EtOAc using a probe blender. After a centrifugation step, removal of residual water and cleanup were performed using dispersive solid-phase extraction (dispersive-SPE) with MgSO(4) and primary secondary amine (PSA) sorbent. (14)C-labeled chlorpyrifos with liquid scintillation counting was used to assist in optimizing and characterizing the method, and GC-ECD and GC-NPD were used for analysis of 24 selected pesticides. The method was validated using tomato, apple and frozen green bean matrices spiked at 0.05, 0.5, and 5 mg/kg. For 22 of the analytes, recoveries averaged 93% for all three commodities over the validation range with a relative standard deviation of 10% (n = 1182). Lower recoveries of dichlorvos were obtained with the method and iprodione determination was compromised in the green beans by an interfering peak. Typical limits of detection were 0.005-0.01 mg/kg with the method.

  6. Multipesticide residue levels in UHT and raw milk samples by GC-μECD after QuEChER extraction method.

    Science.gov (United States)

    Jawaid, Sana; Talpur, Farah N; Nizamani, Shafi M; Khaskheli, Abid A; Afridi, H I

    2016-04-01

    In the present study, milk samples including raw and ultra-high temperature (UHT) processed milk were analyzed for pesticide residue levels, including five pesticides, viz chloripyrifos, endosulfan (α and β), profenofos and bifenthrin by gas chromatography microelectron capture detector (GC-μECD) after extraction by QuEChERS method. Further confirmation of the pesticide residue was done by GC-MS. The pesticide residual level in raw and UHT milk samples (n = 70) was determined in the range of 0.1-30 μg L(-1). All UHT processed milk samples contain pesticide residues within permissible limit set by the World Health Organization (WHO); however, among raw milk samples, chloripyrifos (12 %), α (24 %), and β (14 %) endosulfan were found above the maximum residue limit (MRL). The estimated daily intake (EDI) of these four pesticide residues were also calculated as 1.32, 16.16, 5.30, 10.20, and 9.93 μg kg(-1) body weight for chloripyrifos, endosulfan α, profenofos, endosulfan β, and bifenthrin, respectively. It is concluded that the raw milk samples showed higher prevalence of pesticide residues as compared to UHT processed milk. Graphical abstract Determination of pesticide residues in dairy milk by GC-μECD after QuEChERS extraction method.

  7. Effects of residual feed intake classification and method of alfalfa processing on ewe intake and growth.

    Science.gov (United States)

    Redden, R R; Surber, L M M; Grove, A V; Kott, R W

    2014-02-01

    The objective of this research was to evaluate the effects of residual feed intake (RFI) determined under ad libitum feeding conditions on DMI and performance of yearling ewes fed either chopped or pelleted alfalfa hay. In Exp. 1, 45 ewe-lambs had ad libitum access to a pelleted grower diet for 63 d and individual DMI was determined using an electronic feed delivery system. Residual feed intake values were assigned to each ewe-lamb as a measure of feed efficiency. Sixteen ewe-lambs with the most positive RFI values were classified as high RFI (inefficient) and 16 ewe-lambs with the most negative RFI values were classified as low RFI (efficient). In Exp. 2, half of the ewes from each efficiency group were placed into 1 of 2 pens and provided ad libitum access to either pelleted or chopped alfalfa hay. Individual DMI was again determined using an electronic feed delivery system. Body weight, LM area (LMA), and 12th-rib back fat thickness (BF) were measured at the beginning and end of both experiments. In Exp. 1, DMI by ewe-lambs in the low RFI group was 9% less (P = 0.01) than by ewe-lambs in the high RFI group (2.21 vs. 2.43 kg/d); however, ADG and initial and final BW, LMA, and BF did not differ (P > 0.27) among RFI groups. In Exp. 2, there were no feed processing × RFI group interactions (P > 0.14) for any trait. By design, RFI values were lower (P ewes in the low than high RFI group (-0.27 vs. 0.27); however, RFI values did not differ (P = 1.0) between yearling ewes fed chopped versus pelleted alfalfa. Dry matter intake was 22% less (P ewes in the low than high RFI group (2.5 vs. 3.2 kg/d) and 59% less (P ewes fed chopped versus pelleted alfalfa (2.2 vs. 3.5 kg/d). Initial and final BW, ADG, and G:F did not differ (P > 0.45) between RFI groups but were greater (P ewes fed pelleted alfalfa compared to chopped alfalfa. Final LMA did not differ (P = 0.77) between RFI groups, but final BF tended to be greater (P = 0.06) for high than low RFI yearling ewes (0.63 vs

  8. Prediction of hot spot residues at protein-protein interfaces by combining machine learning and energy-based methods

    Directory of Open Access Journals (Sweden)

    Pontil Massimiliano

    2009-10-01

    Full Text Available Abstract Background Alanine scanning mutagenesis is a powerful experimental methodology for investigating the structural and energetic characteristics of protein complexes. Individual amino-acids are systematically mutated to alanine and changes in free energy of binding (ΔΔG measured. Several experiments have shown that protein-protein interactions are critically dependent on just a few residues ("hot spots" at the interface. Hot spots make a dominant contribution to the free energy of binding and if mutated they can disrupt the interaction. As mutagenesis studies require significant experimental efforts, there is a need for accurate and reliable computational methods. Such methods would also add to our understanding of the determinants of affinity and specificity in protein-protein recognition. Results We present a novel computational strategy to identify hot spot residues, given the structure of a complex. We consider the basic energetic terms that contribute to hot spot interactions, i.e. van der Waals potentials, solvation energy, hydrogen bonds and Coulomb electrostatics. We treat them as input features and use machine learning algorithms such as Support Vector Machines and Gaussian Processes to optimally combine and integrate them, based on a set of training examples of alanine mutations. We show that our approach is effective in predicting hot spots and it compares favourably to other available methods. In particular we find the best performances using Transductive Support Vector Machines, a semi-supervised learning scheme. When hot spots are defined as those residues for which ΔΔG ≥ 2 kcal/mol, our method achieves a precision and a recall respectively of 56% and 65%. Conclusion We have developed an hybrid scheme in which energy terms are used as input features of machine learning models. This strategy combines the strengths of machine learning and energy-based methods. Although so far these two types of approaches have mainly been

  9. VALIDATION HPLC METHOD FOR THE DETERMINATION OF CLONIDINE HYDROCHLORIDE RESIDUES FROM PHARMACEUTICAL MANUFACTURING EQUIPMENT

    Directory of Open Access Journals (Sweden)

    A. V. Yegorova

    2015-04-01

    Full Text Available Highly sensitive HPLC method of determination of clonidine hydrochloride trace amounts for validation cleaning process of the pharmaceutical equipment has been proposed. The developed method has been validated on the following parameters: specificity, linearity, precision, limit of detection and limit of quantification. The calibration curve was linear over the concentration range of 0.1-6.0 mg / ml, the limit of detection is 0.026 μg/ml. It has been found that clonidine hydrochloride solutions are stable for 48 hours. Effectiveness of the method of sampling is more than 95%.

  10. Preliminary validation of high performance liquid chromatography method for detection of methyl-testosterone residue in carp muscle

    Science.gov (United States)

    Jiang, Jie; Lin, Hong; Fu, Xiaoting; Li, Mingming

    2005-07-01

    The use of synthetic anabolic steroid methyltestosterone (MT) as growth promoter is prohibited in China. Validations of analytical methods for MT residue in food and the results obtained have become indispensable. The high performance liquid chromatography (HPLC) method for the detection of MT with liquid-liquid extraction by trichloromethane-methanol in carp muscle tissue was preliminarily validated with reference to the following parameters: recovery (accuracy) at the 1, 5 and l0 mgkg-1 level, between-run and within-run CV values (repeatability, also called relative standard deviation (RSD)) and limit of detection. The recoveries were above 80% and the between-run and within-run CV values below 10% for muscle tissue. The limit of detection was 0.05 mgkg-1.

  11. Evaluation of the localized residual strain states of GaN layers by using a TEM-CBED method

    International Nuclear Information System (INIS)

    Shin, H. Y.; Chang, Y. I.; Jung, Y. W.; Cho, M. J.; Park, K. H.

    2006-01-01

    The convergent beam electron diffraction (CBED) method of transmission electron microscopy (TEM) is well known to be a useful technique for evaluating the localized residual strain by measuring the quantitative variations of the lattice parameters. The multi quantum wells (MQWs) affect on the localized residual strain in a GaN layer, where the AlGaN layer is deposited in order to reduce the strain. We used TEM in order to determine the variations of the lattice parameters of the GaN layer both with and without the AlGaN layer. The lattice parameters of the GaN layer were measured every 100 nm along to the transverse direction below the MQWs. The lattice parameters of the lower part of the GaN layer were shown to have lower values than those of the higher part (below MQWs), which is caused by the compressive stress formed by the sapphire substrate. Also, due to the tensile stress formed by an InGaN in the MQWs, the lattice parameters of the higher part were shown to have higher values. The AlGaN layer deposited on the MQWs produced a compressive stress on the GaN layer so that the average lattice parameters of the GaN layer with the AlGaN layer were lower than those without the AlGaN layer. Therefore, we conclude that the AlGaN layer plays a role in reducing the localized residual strain on the GaN layer below the MQWs.

  12. Comparison of NAA XRF and ICP-OES Methods on Analysis of Heavy Metals in Coals and Combustion Residues

    Directory of Open Access Journals (Sweden)

    Agus Taftazani

    2017-07-01

    Full Text Available Heavy metals in the samples of coals and combustion residues (bottom ash and fly ash from Pacitan coal-fired power plant (CPP have been identified by using NAA, XRF, and ICP-OES methods. This research was aimed to understand the analysis results correlation coefficient (R and determine the enrichment ratio (ER value of the samples by using three analysis methods. The results showed 10 elements have been simultaneously detected in all samples. The correlation coefficient of analysis results of metals content in coals by using NAA-XRF, XRF-ICP OES and with ICPOES-NAA methods gives R2£1 respectively. The correlation coefficient of analysis results of metals content in bottom ash and fly ash by using the methods of NAA-XRF, XRF-ICPOES, and ICPOES-NAA gained R2»1 respectively. ICP-OES method was most satisfactory in this study. The value of ER for identified metals by using the three methods in the samples of bottom ash and fly ash yielded the value over one, and ER value of fly ash was greater in comparison to the bottom ash.

  13. Liquid chromatography-UV diode-array detection method for multi-residue determination of macrolide antibiotics in sheep's milk.

    Science.gov (United States)

    García-Mayor, M A; Garcinuño, R M; Fernández-Hernando, P; Durand-Alegría, J S

    2006-07-28

    A rapid, simple and sensitive liquid chromatography-UV diode-array detection method was developed for the simultaneous determination of seven macrolides (erythromycin, oleandomycin, roxithromycin, josamycin, spiramycin, tylosin and ivermectin) in sheep's milk. The column, mobile phase, temperature and flow rate were optimised to provide the best resolution of these analytes. The extraction of the antibiotic residues involves the treatment of protein-free samples with a combination of concentrated sodium hydroxide and ethyl acetate. Necessary defatting is achieved by alkaline hydrolysis. The recovery of each antibiotic was between 55% and 77%, with relative standard deviations ranging from 1% to 6.5%. The limit of quantification was 72.4 microg/kg for ivermectin, 48.3 microg/kg for roxithromycin, and 24.1 microg/kg for erythromycin, oleandomycin, spiramycin, josamycin and tylosin. The procedure was successfully used in the multi-residue determination of these macrolides at levels below the maximum concentrations legally allowed in milk samples.

  14. A method for computing the inter-residue interaction potentials for ...

    Indian Academy of Sciences (India)

    PRAKASH KUMAR

    2007-06-16

    Jun 16, 2007 ... Wish 1978), which provides a visual representation that gives a clue for rational grouping that accounts ... this fact and proposed a Venn diagram representation of the information contained in Dayhoff's matrix ... The MDS is a widely used method in social sciences and psychometry (Kruskal and Wish 1978).

  15. Method Development for Pesticide Residue Analysis in Farmland Soil using High Perfomance Liquid Chromatography

    Science.gov (United States)

    Theresia Djue Tea, Marselina; Sabarudin, Akhmad; Sulistyarti, Hermin

    2018-01-01

    A method for the determination of diazinon and chlorantraniliprole in soil samples has been developed. The analyte was extracted with acetonitrile from farmland soil sample. Determination and quantification of diazinon and chlorantraniliprole were perfomed by high perfomance liquid chromatography (HPLC) with an UV detector. Several parameters of HPLC method were optimized with respect to sensitivity, high resolution of separation, and accurate determination of diazinon and chlorantraniliprole. Optimum conditions for the separation of two pesticides were eluent composition of acetonitrile:water ratio of 60:40, 0.4 mL/min of flow rate, and 220 nm of wavelength. Under the optimum conditions, diazinon linearity was in the range from 1-25 ppm with R2 of 0.9976, 1.19 mgL-1 LOD, and 3.98 mgL-1 LOQ; while the linearity of chlorantraniliprole was in the range from 0.2-5 mgL-1 with R2 of 0.9972, 0.39 mgL-1 LOD, and 1.29 mgL-1 LOQ. When the method was applied to the soil sample, both pesticides showed acceptable recoveries for real sample of more than 85%: thus, the developed method meets the validation requirement. Under this developed method, the concentrations of both pesticides in the soil samples were below the LOD and LOQ (0.577 mgL-1 for diazinon and 0.007 mgL-1 for chlorantraniliprole). Therefore, it can be concluded that the soil samples used in this study have neither diazinon nor chlorantraniliprole.

  16. Carcinogenicity of residual fuel oils by nonbiological laboratory methods: annotated bibliography. Part I. Laboratory methods of analysis. Part II. Analysis results

    Energy Technology Data Exchange (ETDEWEB)

    Cichorz, R. S.

    1976-04-09

    Recent emphases have been directed by Federal government regulatory agencies and other research groups on the carcinogenic effects of certain aromatic hydrocarbon components in naturally occurring petroleum products. These are used in plant operations, and underline the importance of evaluating environments. Since Rocky Flats Plant uses large quantities of fuel oil, the author was prompted to undertake a search of the chemical literature. Articles and accounts of studies were reviewed on nonbiological laboratory methods for determining the carcinogenicity of residual fuel oils and related high-boiling petroleum fractions. The physical and chemical methods involve the separation or measurement (or both) of polynuclear aromatic constituents which generally are responsible for the carcinogenic effects. Thus, the author suggests that the total carcinogenic activity of any petroleum product may not be due to a specific potent carcinogen, but rather to the cumulative effect of several individually weak carcinogens. The literature search is presented as an annotated bibliography, current as of January 1, 1975, and includes significant parts of the studies along with the total number of other references found when the citation was examined in its entirety. Part I deals with laboratory chemical and physical methods of determining carcinogenicity or polynuclear aromatic hydrocarbons (or both) in residual fuel oils and contains ten entries. Part II includes the results of testing specific fuel oils for carcinogenic constituents and contains eleven entries. An author index and subject categories are included.

  17. Validation of QuEChERS method for the determination of some pesticide residues in two apple varieties.

    Science.gov (United States)

    Tiryaki, Osman

    2016-10-02

    This study was undertaken to validate the "quick, easy, cheap, effective, rugged and safe" (QuEChERS) method using Golden Delicious and Starking Delicious apple matrices spiked at 0.1 maximum residue limit (MRL), 1.0 MRL and 10 MRL levels of the four pesticides (chlorpyrifos, dimethoate, indoxacarb and imidacloprid). For the extraction and cleanup, original QuEChERS method was followed, then the samples were subjected to liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) for chromatographic analyses. According to t test, matrix effect was not significant for chlorpyrifos in both sample matrices, but it was significant for dimethoate, indoxacarb and imidacloprid in both sample matrices. Thus, matrix-matched calibration (MC) was used to compensate matrix effect and quantifications were carried out by using MC. The overall recovery of the method was 90.15% with a relative standard deviation of 13.27% (n = 330). Estimated method detection limit of analytes blew the MRLs. Some other parameters of the method validation, such as recovery, precision, accuracy and linearity were found to be within the required ranges.

  18. Multi-residue method for detecting coccidiostats at carry-over level in feed by HPLC-MS/MS.

    Science.gov (United States)

    Delahaut, Ph; Pierret, G; Ralet, N; Dubois, M; Gillard, N

    2010-06-01

    A multi-residue HPLC-ESI-MS/MS method has been developed for the simultaneous extraction, detection and confirmation of the 11 coccidiostats referenced by Regulation 2009/8/EC (lasalocid sodium, narasin, salinomycin sodium, monensin sodium, semduramicin sodium, maduramicin ammonium alpha, robenidine hydrochloride, decoquinate, halofuginone hydrobromide, nicarbazin, and diclazuril) in feedstuffs at carry-over level. The sensitivity of the method allows quantification and confirmation for all coccidiostats below target concentration. The method was in-house validated and meets all criteria of European legislation (2002/657/EC). The precision of the method was determined under repeatability and within-laboratory reproducibility conditions; RSD(r) and RSD(R) were below the maximum permitted values for every tested concentration. The specificity was checked by analysing representative blank samples and blank samples fortified with potentially interfering substances (benzimidazoles, corticosteroides, triphenylmethane dyes, quinolones, nitrofurans, nitroimidazoles, phenicols); no interference were found. Concerning quantification, a quadratic regression model was fitted to every calibration curve with a regression coefficient r2 above 0.99 on each data set. Finally, the expanded uncertainty U was calculated with data obtained within the laboratory while applying the method during validation and in routine tests.

  19. Evaluation of SW846 Method 8330 for Characterization of Sites Contaminated with Residues of High Explosives

    Science.gov (United States)

    1993-06-01

    the transformation pathways of some explosives have Method 8330 is the sum of the TNB and TNBA initially been studied in cell cultures , composting...soil. Talanta, 39:419-428. products in soils and plant tissues by high-performance Jenkins, T.F., P.H. Miyares, K.F. Myers, E.F. McCor- liquid... hydroponic plants. Environmental Toxicology and (1976)Aquaticfield survey at Iowa, Radford, and Joliet Chemistry, 10: 845-855. Armn Ammunition Plants

  20. Evaluating The Methods For Postvoiding Residual Volume Assesment And Factors That May Influence The Results

    Directory of Open Access Journals (Sweden)

    Unal Bicakci

    2017-12-01

    Conclusion: Measurement of PVR by portable ultrasonography yields comparable results with urethral catheterization. Although PVR measurement on VCUG images is a less reliable method, it can provide additional information in certain conditions (ie. VUR, diverticulum... Although statistical significance could not be demonstrated, we believe that VUR, renal scaring and bladder trabeculation may interfere with the results of PVR assessments. [J Contemp Med 2017; 7(4.000: 329-332

  1. Development of Radiometric and Allied Analytical Methods and Strategies to Strengthen National Residue Control Programmes for Antibiotic and Anthelmintic Veterinary Drug Residues. Final Report of a Coordinated Research Project

    International Nuclear Information System (INIS)

    2016-08-01

    Awareness of food safety is rising among consumers, and many importing countries implement food control regulations to guarantee the quality and safety of imported foods for their consumers. Many developing countries have also taken steps to put in place control systems that encourage responsible use of veterinary medicines to combat possible drug resistance, control drug residues and ensure compliance with international and national standards. However, these countries still require the necessary know-how and skills to protect local consumers and to access international markets. One significant constraint is the capacity of laboratory services to generate surveillance data using reliable and cost effective analytical methods validated to national and international standards. The IAEA coordinated research project (CRP) on the Development of Radiometric and Allied Analytical Methods to Strengthen National Residue Control Programmes for Antibiotic and Anthelmintic Veterinary Drug Residues was initiated in 2009 to conduct work on robust nuclear and related technologies suitable for the screening and confirmatory analysis of residues of veterinary medicines, including antimicrobials and anthelmintics commonly used in animal production, with public health and trade significance. The CRP also explored mechanisms to enhance networking among research institutions involved in research on pharmacologically active veterinary drug residues in food (primarily) and environmental samples. The project was implemented by the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture between 2009 and 2014 and involved eleven research contracts and one technical contract, five research agreements and one institution. The CRP was a continuation of the CRP on the Development of Strategies for the Effective Monitoring of Veterinary Drug Residues in Livestock and Livestock Products in Developing Countries and the key findings are also summarized in this publication.

  2. Study on the residual stress relaxation in girth-welded steel pipes under bending load using diffraction methods

    International Nuclear Information System (INIS)

    Hempel, Nico; Nitschke-Pagel, Thomas; Dilger, Klaus

    2017-01-01

    This research is dedicated to the experimental investigation of the residual stress relaxation in girth-welded pipes due to quasi-static bending loads. Ferritic-pearlitic steel pipes are welded with two passes, resulting in a characteristic residual stress state with high tensile residual stresses at the weld root. Also, four-point bending is applied to generate axial load stress causing changes in the residual stress state. These are determined both on the outer and inner surfaces of the pipes, as well as in the pipe wall, using X-ray and neutron diffraction. Focusing on the effect of tensile load stress, it is revealed that not only the tensile residual stresses are reduced due to exceeding the yield stress, but also the compressive residual stresses for equilibrium reasons. Furthermore, residual stress relaxation occurs both parallel and perpendicular to the applied load stress.

  3. Indirect [3H]methyl exchange as a general method for labeling methionine residues: application to calcitonin.

    Science.gov (United States)

    Barling, P M; Preston, J R; Bibby, N J; Wilson, T

    1985-02-01

    Native porcine calcitonin from Armour is known to contain two components. It is shown that these can be separated by cation-exchange chromatography in 8 M urea. The technique of [3H]methyl exchange on the methionine residue was used to prepare each of these in a tritiated form. The reduced components formed by demethylation were found to readily reoxidize at neutral pH, to regenerate the disulfide bridge. Evidence is provided to show that the two forms were partially interconverted during these steps. The reoxidized 3H-labeled products were found to be indistinguishable in chemical, immunological, and biological properties from the equivalent components in native porcine calcitonin and had specific activities of approximately 20 Ci/mmol. It is concluded that this labeling method can be conveniently applied to peptides containing one or more disulfide bridges, to give products of high specific activity in acceptable yield, provided appropriate conditions are used to ensure correct reoxidation occurs.

  4. Use of mass spectrometry methods as a strategy for detection and determination of residual solvents in pharmaceutical products.

    Science.gov (United States)

    Pérez Pavón, José Luis; del Nogal Sanchez, Miguel; García Pinto, Carmelo; Fernandez Laespada, M Esther; Moreno Cordero, Bernardo

    2006-07-15

    In the present work a strategy for the qualitative and quantitative analysis of residual solvents in pharmaceutical products is reported. First, a low-resolution chromatogram is generated for the identification of the solvents present in the samples by means of headspace generation-fast gas chromatography-mass spectrometry (HS-fast GC/MS). From the plotting of this information by means of contour plots with time and mass/charge axes, it is decided whether quantification of such compounds can be accomplished without chromatographic separation or whether it should be done by fast gas chromatography. The nonseparative method is based on direct coupling of a headspace sampler with a mass spectrometer (HS-MS) and requires a signal recording time of only 3 min, while with fast gas chromatography the time required to obtain a chromatogram is 7.16 min. The use of headspace generation for introducing the sample and standard addition as a quantification technique provided satisfactory results and minimized the matrix effect. An important advantage of the methodologies used here is related to the fact that no prior treatment of the sample is required, thus minimizing the creation of analytical artifacts and the errors associated with this step of the analytical process. The methods were applied to the determination of residual solvents in 27 different pharmaceutical products. Detection and quantitation limits were sufficiently low to enable the estimation of organic volatile impurities according to the International Conference on Harmonization (ICH) of Technical Requirements for the Registration of Pharmaceuticals for Human Use.

  5. Energy dependent mesh adaptivity of discontinuous isogeometric discrete ordinate methods with dual weighted residual error estimators

    Science.gov (United States)

    Owens, A. R.; Kópházi, J.; Welch, J. A.; Eaton, M. D.

    2017-04-01

    In this paper a hanging-node, discontinuous Galerkin, isogeometric discretisation of the multigroup, discrete ordinates (SN) equations is presented in which each energy group has its own mesh. The equations are discretised using Non-Uniform Rational B-Splines (NURBS), which allows the coarsest mesh to exactly represent the geometry for a wide range of engineering problems of interest; this would not be the case using straight-sided finite elements. Information is transferred between meshes via the construction of a supermesh. This is a non-trivial task for two arbitrary meshes, but is significantly simplified here by deriving every mesh from a common coarsest initial mesh. In order to take full advantage of this flexible discretisation, goal-based error estimators are derived for the multigroup, discrete ordinates equations with both fixed (extraneous) and fission sources, and these estimators are used to drive an adaptive mesh refinement (AMR) procedure. The method is applied to a variety of test cases for both fixed and fission source problems. The error estimators are found to be extremely accurate for linear NURBS discretisations, with degraded performance for quadratic discretisations owing to a reduction in relative accuracy of the "exact" adjoint solution required to calculate the estimators. Nevertheless, the method seems to produce optimal meshes in the AMR process for both linear and quadratic discretisations, and is ≈×100 more accurate than uniform refinement for the same amount of computational effort for a 67 group deep penetration shielding problem.

  6. Parallel fast multipole boundary element method applied to computational homogenization

    Science.gov (United States)

    Ptaszny, Jacek

    2018-01-01

    In the present work, a fast multipole boundary element method (FMBEM) and a parallel computer code for 3D elasticity problem is developed and applied to the computational homogenization of a solid containing spherical voids. The system of equation is solved by using the GMRES iterative solver. The boundary of the body is dicretized by using the quadrilateral serendipity elements with an adaptive numerical integration. Operations related to a single GMRES iteration, performed by traversing the corresponding tree structure upwards and downwards, are parallelized by using the OpenMP standard. The assignment of tasks to threads is based on the assumption that the tree nodes at which the moment transformations are initialized can be partitioned into disjoint sets of equal or approximately equal size and assigned to the threads. The achieved speedup as a function of number of threads is examined.

  7. Optimization of a method by liquid chromatography of high resolution to determine residues of ethilenthiourea in samples of tomato

    International Nuclear Information System (INIS)

    Mora, D.; Rodriguez, O.M.

    2002-01-01

    A method was optimized to determine the present residues of ethilenthiourea in samples of tomatoes. The method consisted of three stages: a extraction of ultrasonic bath with methanol; a cleaning of the extract through a glass column of 11 mm of diameter stuffed with 2,5 g of neutral aluminium's mixture and activated coal (97,5:2,5) and 2,5 g of pure-neutral aluminium, it is dissolved with 250 ml of methanol. The third stage was of quantification by HPLC in a C 18 ' column with a methanol and water mixture (90:10) like a mobile phase to an flow of 2,0 ml/min. and with UV detection to 232 nm. The retention's time under theses conditions was of 2,15 minutes. The merit's parameters of the method were determined, proving and lineal sphere between 1,0 and 28,0 (g/ml of ETU; some quantification and detection limits have been calculated by the method of Hubaux and Vos (22) of 0,153 and 0,306 mg/ml respectively and a recuperation of 84%. (Author) [es

  8. Grouping of residual solvents present in pharmaceuticals using experimental planning and chemometric methods.

    Science.gov (United States)

    Grodowska, Katarzyna; Parczewski, Andrzej

    2013-01-01

    The main effects of six experimental factors on the efficiency of HS (headspace) extraction in headspace gas chromatography--flame ionization detector (HS-GC-FID) determination of twenty organic solvents routinely used in production of pharmaceuticals were obtained on the basis of the results of experiments carried out according to the Plackett-Burman factorial design. The effects were used as a basis for grouping the solvents into five groups, the solvents belonging to a group responded similarly to changes of HS conditions. To this end, visualization approaches were used as well as chemometric methods: cluster analysis (CA) and principal component analysis (PCA). Moreover, the most important HS experimental factors were selected for further optimization of the HS-GC determination procedure.

  9. Occurrence of erythromycin residues in sheep milk. Validation of an analytical method.

    Science.gov (United States)

    García-Mayor, M A; Paniagua-González, G; Soledad-Rodríguez, B; Garcinuño-Martínez, R M; Fernández-Hernando, P; Durand-Alegría, J S

    2015-04-01

    The paper describes a new and selective analytical sample treatment for quantitative extraction and preconcentration of erythromycin in presence of other macrolide antibiotics in sheep milk samples. The methodology is based on the use of a molecular imprinted polymer (MIP) employed as solid phase extraction sorbent (MISPE). The synthesized material by bulk polymerization using erythromycin (ERY) as template was evaluated as solid phase extraction sorbent, in a novel sample treatment technique that can be coupled to high-performance liquid chromatography with diode-array detector (HPLC-DAD). MIP selectivity was studied for other macrolide antibiotics with similar structures, such as tylosin (TYL), spiramycin (SPI), josamycin (JOS), roxithromycin (ROX) and ivermectin (IVER) getting recoveries for these interferents lower than 35%, for all cases except for ROX, which recoveries were around 85%. The variables affecting the molecularly imprinted solid-phase extraction (MISPE) procedure were optimized to select the best conditions of selectivity and sensitivity to determine ERY at concentration levels established by EU legislation in sheep milk. Under the selected experimental conditions, quantification limit was 24.1 µg kg(-1). Recoveries were higher than 98%, with RSDs between 0.7% and 2%. The proposed MISPE-HPLC method was validated and successfully applied to ERY analysis in sheep milk samples. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Fracture Toughness Prediction under Compressive Residual Stress by Using a Stress-Distribution T-Scaling Method

    Directory of Open Access Journals (Sweden)

    Toshiyuki Meshii

    2017-12-01

    Full Text Available The improvement in the fracture toughness Jc of a material in the ductile-to-brittle transition temperature region due to compressive residual stress (CRS was considered in this study. A straightforward fracture prediction was performed for a specimen with mechanical CRS by using the T-scaling method, which was originally proposed to scale the fracture stress distributions between different temperatures. The method was validated for a 780-MPa-class high-strength steel and 0.45% carbon steel. The results showed that the scaled stress distributions at fracture loads without and with CRS are the same, and that Jc improvement was caused by the loss in the one-to-one correspondence between J and the crack-tip stress distribution. The proposed method is advantageous in possibly predicting fracture loads for specimens with CRS by using only the stress–strain relationship, and by performing elastic-plastic finite element analysis, i.e., without performing fracture toughness testing on specimens without CRS.

  11. Rapid gas chromatographic method for the determination of famoxadone, trifloxystrobin and fenhexamid residues in tomato, grape and wine samples.

    Science.gov (United States)

    Likas, D T; Tsiropoulos, N G; Miliadis, G E

    2007-05-25

    Trifloxystrobin, fenhexamid and famoxadone belong to the generation of fungicides acting against a broad spectrum of fungi and widely used in Integrated Pest Management strategies in different agricultural crops but mainly in viticulture. In the present work, a gas chromatographic (GC) method for their determination was developed and validated on tomato, grape and wine matrices. The method was based on a simple one step liquid-liquid microextraction with cyclohexane/dichloromethane (9+1, v/v) and determination of fungicides by gas chromatography with nitrogen phosphorous (NP-) and electron capture (EC-) detection, and ion trap mass spectrometry (ITMS) for confirmation. The method was validated by recovery experiments, assessment of matrix effect and calculation of the associated uncertainty. Recoveries for GC-NPD and GC-ECD were found in the range of 81-102% with RSD NPD, respectively, depending on the sensitivity of each compound with trifloxystrobin being the most sensitive. The expanded uncertainty, calculated for a sample concentration of 0.10 mg/kg, ranged from 4.8 to 13% for the GC-ECD and from 5.4 to 29% for the GC-NPD. The concentration levels for famoxadone residues found in tomato and grape samples from field experiments were clearly below the EU established MRL values, thus causing no problems in terms of food safety.

  12. Multi-rate cubature Kalman filter based data fusion method with residual compensation to adapt to sampling rate discrepancy in attitude measurement system.

    Science.gov (United States)

    Guo, Xiaoting; Sun, Changku; Wang, Peng

    2017-08-01

    This paper investigates the multi-rate inertial and vision data fusion problem in nonlinear attitude measurement systems, where the sampling rate of the inertial sensor is much faster than that of the vision sensor. To fully exploit the high frequency inertial data and obtain favorable fusion results, a multi-rate CKF (Cubature Kalman Filter) algorithm with estimated residual compensation is proposed in order to adapt to the problem of sampling rate discrepancy. During inter-sampling of slow observation data, observation noise can be regarded as infinite. The Kalman gain is unknown and approaches zero. The residual is also unknown. Therefore, the filter estimated state cannot be compensated. To obtain compensation at these moments, state error and residual formulas are modified when compared with the observation data available moments. Self-propagation equation of the state error is established to propagate the quantity from the moments with observation to the moments without observation. Besides, a multiplicative adjustment factor is introduced as Kalman gain, which acts on the residual. Then the filter estimated state can be compensated even when there are no visual observation data. The proposed method is tested and verified in a practical setup. Compared with multi-rate CKF without residual compensation and single-rate CKF, a significant improvement is obtained on attitude measurement by using the proposed multi-rate CKF with inter-sampling residual compensation. The experiment results with superior precision and reliability show the effectiveness of the proposed method.

  13. Krylov methods for compressible flows

    Science.gov (United States)

    Tidriri, M. D.

    1995-01-01

    We investigate the application of Krylov methods to compressible flows, and the effect of implicit boundary conditions on the implicit solution of nonlinear problems. Two defect-correction procedures, namely, approximate factorization (AF) for structured grids and ILU/GMRES for general grids, are considered. Also considered here are Newton-Krylov matrix-free methods that we combined with the use of mixed discretization schemes in the implicitly defined Jacobian and its preconditioner. Numerical experiments that show the performance of our approaches are then presented.

  14. State of the art in the validation of screening methods for the control of antibiotic residues: is there a need for further development?

    Science.gov (United States)

    Gaudin, Valérie

    2017-09-01

    Screening methods are used as a first-line approach to detect the presence of antibiotic residues in food of animal origin. The validation process guarantees that the method is fit-for-purpose, suited to regulatory requirements, and provides evidence of its performance. This article is focused on intra-laboratory validation. The first step in validation is characterisation of performance, and the second step is the validation itself with regard to pre-established criteria. The validation approaches can be absolute (a single method) or relative (comparison of methods), overall (combination of several characteristics in one) or criterion-by-criterion. Various approaches to validation, in the form of regulations, guidelines or standards, are presented and discussed to draw conclusions on their potential application for different residue screening methods, and to determine whether or not they reach the same conclusions. The approach by comparison of methods is not suitable for screening methods for antibiotic residues. The overall approaches, such as probability of detection (POD) and accuracy profile, are increasingly used in other fields of application. They may be of interest for screening methods for antibiotic residues. Finally, the criterion-by-criterion approach (Decision 2002/657/EC and of European guideline for the validation of screening methods), usually applied to the screening methods for antibiotic residues, introduced a major characteristic and an improvement in the validation, i.e. the detection capability (CCβ). In conclusion, screening methods are constantly evolving, thanks to the development of new biosensors or liquid chromatography coupled to tandem-mass spectrometry (LC-MS/MS) methods. There have been clear changes in validation approaches these last 20 years. Continued progress is required and perspectives for future development of guidelines, regulations and standards for validation are presented here.

  15. Evaluation of Pentachlorophenol Residues in Some Hygienic Papers Prepared from Virgin and Secondary Pulp by Electron Capture Gas Chromatographic Method

    Directory of Open Access Journals (Sweden)

    Behrouz Akbari-adergani

    2016-01-01

    Full Text Available In this study, residual amount of pentachlorophenol (PCP as the most important paper preservative, which is extremely hazardous pollutant, was determined in some tissue papers and napkins. Twenty-five samples of two producing hygienic paper factories prepared from virgin and secondary pulp were analyzed for the presence of trace amount of PCP. The analytical procedure involved direct extraction of PCP from hygienic paper and its determination by gas chromatography with electron capture detection. The statistical results for the analysis of all samples revealed that there were significant differences between mean of PCP in hygienic papers prepared from virgin and secondary pulp (P<0.05. This method gave recoveries of 86-98% for hygienic paper made from virgin pulp and 79-92% for hygienic paper made from secondary pulp. The limit of detection (LOD and limit of quantification (LOQ for PCP were 6.3 and 21.0 mg/kg, respectively. The analytical method has the requisite sensitivity, accuracy, precision and specificity to assay PCP in hygienic papers. This study demonstrates a concern with exposition to PCP considering that hygienic paper is largely consumed in the society.

  16. Liquid chromatography – tandem mass spectrometry method for the determination of ten tetracycline residues in muscle samples

    Directory of Open Access Journals (Sweden)

    Gajda Anna

    2015-09-01

    Full Text Available A liquid chromatography – tandem mass spectrometry (LC-MS/MS method for the determination of oxytetracycline (OTC, 4-epi oxytetracycline (4-epi OTC, tetracycline (TC, 4-epi tetracycline (4-epi TC, chlortetracycline (CTC, 4-epi chlortetracycline (4-epi CTC, doxycycline (DC, minocycline (MINO, methacycline (META and rolitetracycline (ROLI residues in muscles was developed. The procedure consisted of an oxalic acid extraction followed by protein removal with trichloroacetic acid. Further solid phase clean-up on polymeric (Strata X reversed phase columns was performed to obtain an extract suitable for LC-MS/MS analysis. The tetracyclines were separated on a C 18 analytical column with mobile phase consisting of 0.01% formic acid in acetonitrile and 0.01% formic acid in water in gradient mode. The method was validated according to the Commission Decision 2002/657/EC. The recoveries of all target compounds were 91.8% – 103.6%. The decision limits were from 109.0 to 119.8 μg/kg and detection capability varied within the range of 122.2 to 137.6 μg/kg, depending on the analyte.

  17. Application and evaluation of a high-resolution mass spectrometry screening method for veterinary drug residues in incurred fish and imported aquaculture samples.

    Science.gov (United States)

    Turnipseed, Sherri B; Storey, Joseph M; Wu, I-Lin; Gieseker, Charles M; Hasbrouck, Nicholas R; Crosby, Tina C; Andersen, Wendy C; Lanier, Shanae; Casey, Christine R; Burger, Robert; Madson, Mark R

    2018-02-14

    The ability to detect chemical contaminants, including veterinary drug residues in animal products such as fish, is an important example of food safety analysis. In this paper, a liquid chromatography high-resolution mass spectrometry (LC-HRMS) screening method using a quadrupole-Orbitrap instrument was applied to the analysis of veterinary drug residues in incurred tissues from aquacultured channel catfish, rainbow trout, and Atlantic salmon and imported aquacultured products including European eel, yellow croaker, and tilapia. Compared to traditional MS methods, the use of HRMS with nontargeted data acquisition and exact mass measurement capability greatly increased the scope of compounds that could be monitored simultaneously. The fish samples were prepared for analysis using a simple efficient procedure that consisted of an acidic acetonitrile extraction followed by solid phase extraction cleanup. Two different HRMS acquisition programs were used to analyze the fish extracts. This method detected and identified veterinary drugs including quinolones, fluoroquinolones, avermectins, dyes, and aminopenicillins at residue levels in fish that had been dosed with those compounds. A metabolite of amoxicillin, amoxicillin diketone, was also found at high levels in catfish, trout, and salmon. The method was also used to characterize drug residues in imported fish. In addition to confirming findings of fluoroquinolone and sulfonamide residues that were found by traditional targeted MS methods, several new compounds including 2-amino mebendazole in eel and ofloxacin in croaker were detected and identified. Graphical Abstract Aquacultured samples are analyzed with a high-resolution mass spectrometry screening method to detect and identify unusual veterinary drug residues including ofloxacin in an imported fish.

  18. Effect of process variables on the Drucker-Prager cap model and residual stress distribution of tablets estimated by the finite element method.

    Science.gov (United States)

    Hayashi, Yoshihiro; Otoguro, Saori; Miura, Takahiro; Onuki, Yoshinori; Obata, Yasuko; Takayama, Kozo

    2014-01-01

    A multivariate statistical technique was applied to clarify the causal correlation between variables in the manufacturing process and the residual stress distribution of tablets. Theophylline tablets were prepared according to a Box-Behnken design using the wet granulation method. Water amounts (X1), kneading time (X2), lubricant-mixing time (X3), and compression force (X4) were selected as design variables. The Drucker-Prager cap (DPC) model was selected as the method for modeling the mechanical behavior of pharmaceutical powders. Simulation parameters, such as Young's modulus, Poisson rate, internal friction angle, plastic deformation parameters, and initial density of the powder, were measured. Multiple regression analysis demonstrated that the simulation parameters were significantly affected by process variables. The constructed DPC models were fed into the analysis using the finite element method (FEM), and the mechanical behavior of pharmaceutical powders during the tableting process was analyzed using the FEM. The results of this analysis revealed that the residual stress distribution of tablets increased with increasing X4. Moreover, an interaction between X2 and X3 also had an effect on shear and the x-axial residual stress of tablets. Bayesian network analysis revealed causal relationships between the process variables, simulation parameters, residual stress distribution, and pharmaceutical responses of tablets. These results demonstrated the potential of the FEM as a tool to help improve our understanding of the residual stress of tablets and to optimize process variables, which not only affect tablet characteristics, but also are risks of causing tableting problems.

  19. Methods to enhance hydrolysis during one and two-stage anaerobic digestion of energy crops and crop residues

    Energy Technology Data Exchange (ETDEWEB)

    Jagadabhi, P. S.

    2011-07-01

    The objective of this thesis was to evaluate methods to enhance hydrolysis (measured as specific SCOD production, g SCOD g-1 VS) during one and two-stage anaerobic digestion (AD) of energy crops and crop residues. Addition of macro (NH{sub 4}Cl), micro nutrients (Fe, Ni, Co and Mo) and leachate replacement during mono-digestion of grass silage in one-stage leach bed reactors (LBRs) enhanced hydrolysis by 18 % (0.56 g SCOD g-1 VS), 7 % (0.45 g SCOD g-1 VS) and 34 % (0.51 g SCOD g-1 VS) respectively compared to respective controls. On the other hand, creating micro-aerobic conditions (at 1 l min-1, 2.5 l of air) did not improve hydrolysis but enhanced VFA production by 4 fold (from 2.2 g l-1 to 9 g l-1). Application of rumen cultures improved hydrolysis by 10 % (0.33 g SCOD g-1 VS) more than control (0.30 g SCOD g-1 VS). Similarly, during two-stage AD in LBR-UASB reactor configuration leachate replacement enhanced hydrolysis in cucumber and grass silage (0.5 g SCOD g-1 VS) than in tomato and common reed (0.35 and 0.15 g SCOD g-1 VS respectively). During co-digestion of grass silage and cow manure at a ratio of 30:70 (VS) in CSTR, re-circulation of alkali treated solid fraction of digestate did not improve the anaerobic biodegradation rates or methane yields. Results from batch experiments showed that methane potential of grass silage varied from 0.28-0.39 m3 CH{sub 4} kg-1 VS{sub added} in all the experiments. On the other hand, methane potentials of the studied crop residues were 0.32 m3 CH{sub 4} kg-1 VS{sub added} for tomato and 0.26 m3 CH{sub 4} kg-1 VS{sub added} for cucumber and common reed. Alkali pretreatment of solids, obtained from digestate (during co-digestion of grass silage and cow manure in one-stage CSTRs), at a low concentration of 20 g NaOH kg-1 VS resulted in higher methane yield (0.34 m3 CH{sub 4} kg-1 VS{sub added}) than the other tested dosages (40 and 60 g NaOH kg-1 VS). Addition of macro nutrient (NH{sub 4}Cl) enhanced methane potential of

  20. A multi-residue method for characterization of endocrine disruptors in gaseous and particulate phases of ambient air

    Science.gov (United States)

    Alliot, Fabrice; Moreau-Guigon, Elodie; Bourges, Catherine; Desportes, Annie; Teil, Marie-Jeanne; Blanchard, Martine; Chevreuil, Marc

    2014-08-01

    A number of semi-volatile compounds occur in indoor air most of them being considered as potent endocrine disruptors and thus, exerting a possible impact upon health. To assess their concentration levels in indoor air, we developed and validated a method for sampling and multi-residue analysis of 58 compounds including phthalates, polycyclic aromatic hydrocarbons (PAHs), polybromodiphenylethers (PBDEs), polychlorobiphenyls (PCBs), parabens, bisphenol A (BPA) and tetrabromobisphenol A (TBBPA) in gaseous and particulate phases of air. We validated each step of procedures from extraction until analysis. Matrice spiking were performed at extraction, fractionation and purification stages. The more volatile compounds were analyzed with a gas chromatography system coupled with a mass spectrometer (GC/MS) or with a tandem mass spectrometer (GC/MS/MS). The less volatile compounds were analyzed with a liquid chromatography system coupled with a tandem mass spectrometer (LC/MS/MS). Labeled internal standard method was used ensuring high quantification accuracy. The instrumental detection limits were under 1 pg for all compounds and therefore, a limit of quantification averaging 1 pg m-3 for the gaseous and the particulate phases and a volume of 150 m3, except for phthalates, phenol compounds and BDE-209. Satisfactory recoveries were found except for phenol compounds. That method was successfully applied to several indoor air samples (office, apartment and day nursery) and most of the targeted compounds were quantified, mainly occurring in the gaseous phase. The most abundant were phthalates (up to 918 ng m-3 in total air), followed by PCBs > parabens > BPA > PAHs > PBDEs.

  1. Analytical method for the determination of cyromazine and melamine residues in soil using LC-UV and GC-MSD.

    Science.gov (United States)

    Yokley, R A; Mayer, L C; Rezaaiyan, R; Manuli, M E; Cheung, M W

    2000-08-01

    A method is reported for the determination of cyromazine and melamine residues in soil. Soil samples are extracted twice via mechanical shaking, each time with 70% acetonitrile/30% 0.050 M ammomium carbonate for 30 min. An aliquot portion of the pooled extracts is subjected to strong cation exchange (SCX) purification on AG 50W-X4 resin. Final analysis is accomplished using liquid chromatography-ultraviolet (LC-UV) detection at a wavelength of 214 nm. Confirmatory analyses can be performed using gas chromatography-mass selective detection (GC-MSD) in the selected ion monitoring (SIM) mode. The limit of detection (LOD) is 2.5 ng injected and the limit of quantification (LOQ) is 10 ppb when using LC-UV for the analysis of N-cyclopropyl-1,3,5-triazine-2,4, 6-triamine (cyromazine) and 1,3,5-triazine-2,4,6-triamine (melamine). The LOD is 0.050 ng injected and the LOQ is 10 ppb when using GC-MSD for confirmatory analyses. The mean procedural recoveries were 97 and 95% and the standard deviations were 16 and 11% for cyromazine and melamine, respectively (n = 24), when using LC-UV. The mean procedural recoveries were 107 and 92% and the standard deviations were 9.9 and 16% for cyromazine and melamine, respectively (n = 29), when using GC-MSD. The method validation study was conducted under U.S. EPA FIFRA Good Laboratory Practice Guidelines 40 CFR 160. The method also passed an Independent Laboratory Validation (ILV) as per U.S. EPA FIFRA Subdivision N.

  2. Increased component safety through improved methods for residual stress analysis. Subprojects. Consideration of the elastic-plastic material properties (Phase 2). Final report

    International Nuclear Information System (INIS)

    Mirbach, David von

    2015-01-01

    Residual stresses in mechanical components can result in both detrimental but also beneficial effects on the strength and lifetime of the components. The most detailed knowledge of the residual stress state is of advantage or a pre-requisite for the assessment of the component performance. Two commonly used methods for determination of residual stresses are the hole drilling method and the ring core method which can be regarded to the mechanical methods. In the context of reactor safety research of the German Federal Ministry of Economic and Energy (BMWi) two fundamental and interacting weak points of the hole drilling method as well as of the ring core method, respectively, in order to determine residual stresses are going to be investigated. As a consequence reliability of the methods will be improved in this joint research project. On the one hand there are effects of geometrical boundary conditions of the components and on the other hand there is the influence of plasticity due to notch effects both affecting the released strain field after removing material and after all the calculated residual stresses. The first issue mentioned above is under the responsibility of the Institute of Materials Engineering (Kassel University) and the last one is investigated by materials testing institute university Stuttgart. As a consequence of a successful project the knowledge base will be considerably improved resulting in benefits for various engineering fields. Especially the quantitative consideration of real residual stress states for optimized component designs will be possible and after all the consequences of residual stresses on safety of components which are used in nuclear facilities can be evaluated. In this second experimental research chapter (phase 2) the findings of the first numerical and theoretical research chapter (phase 1) where proofed. The developed differential calculation method with the method of adaptive calibration functions were compared with the

  3. Improvement in accuracy of the measurements of residual stresses due to circumferential welds in thin-walled pipe using Rayleigh wave method

    International Nuclear Information System (INIS)

    Akhshik, Siamak; Moharrami, Rasool

    2009-01-01

    To achieve an acceptable safety in many industrial applications such as nuclear power plants and power generation, it is extremely important to gain an understanding of the magnitudes and distributions of the residual stresses in a pipe formed by joining two sections with a girth butt weld. Most of the methods for high-accuracy measurement of residual stress are destructive. These destructive measurement methods cannot be applied to engineering systems and structures during actual operation. In this paper, we present a method based on the measurement of ultrasonic Rayleigh wave velocity variations versus the stress state for nondestructive evaluation of residual stress in dissimilar pipe welded joint. We show some residual stress profile obtained by this method. These are then compared with other profiles determined using a semi-destructive technique (hole-drilling) that makes it possible to check our results. According to the results, we also present a new method for adjusting the ultrasonic measurements to improve the agreement with the results obtained from other techniques.

  4. In-house method validation and occurrence of alpha-, beta-endosulfan, endosulfan sulphate, lambda-cyhalothrin, procymidone and trifluralin residues in strawberry

    Directory of Open Access Journals (Sweden)

    Alexandre Augusto Soares

    2013-12-01

    Full Text Available A method for determination of organohalogen pesticides in strawberry by gas chromatography with electron capture detection was validated and applied in a monitoring program. Linearity, matrix effects, and day effect were evaluated for the analytes alpha-endosulfan, beta-endosulfan, endosulfan sulphate, lambda-cyhalothrin, procymidone, and trifluralin. The linear range varied according to the chromatographic response of the analyte. Significant matrix effects were observed. The mean recoveries ranged from 74.6 to 115.4%, with repeatability standard deviations between 1.6 and 21.0% and intermediate precision between 5.9 and 21.0%. Detection, quantification and decision limit, and detection capacity ranged from 0.003 to 0.007 mg/kg, 0.005 to 0.013 mg/kg; 0.003 to 3.128 mg/kg; and 0.005 to 3.266 mg/kg, respectively. The method was fit for the purpose of monitoring organohalogen residues in strawberries. Residues of these pesticides were detected in 124 of the 186 samples analyzed between 2009 and 2011 in the state of Minas Gerais. Nine of them did not comply with the current legislation requirements; among them, seven (3.8% had residues of unauthorized pesticide for the culture of strawberry, one (0.5% had residues above the maximum residue limit, and another one (0.5% exhibited both non-conformities.

  5. Residual gas analysis

    International Nuclear Information System (INIS)

    Berecz, I.

    1982-01-01

    Determination of the residual gas composition in vacuum systems by a special mass spectrometric method was presented. The quadrupole mass spectrometer (QMS) and its application in thin film technology was discussed. Results, partial pressure versus time curves as well as the line spectra of the residual gases in case of the vaporization of a Ti-Pd-Au alloy were demonstrated together with the possible construction schemes of QMS residual gas analysers. (Sz.J.)

  6. Effect of processing conditions and methods on residual stress in CeO2 buffer layers and YBCO superconducting films

    International Nuclear Information System (INIS)

    Xiong Jie; Qin Wenfeng; Cui Xumei; Tao Bowan; Tang Jinlong; Li Yanrong

    2006-01-01

    CeO 2 layers have been fabricated by pulsed laser deposition (PLD) technique on (1 1 0 2) sapphire substrate. Microstructure of CeO 2 layers is characterized by X-ray diffraction as functions of substrate temperature. The effects of the substrate temperature on the residual stress have been studied. The results show that residual stress in CeO 2 film decreased with increasing substrate temperature, not the same development tendency as that of thermal stress. This means that the thermal stress is only a fraction of the residual stress. Moreover, YBCO superconducting films were prepared by direct current (DC) sputtering and pulsed laser deposition (PLD) technique. The residual stress and thermal stress of both YBCO films were measured. PLD processing apparently generated higher intrinsic compressive stresses in comparison to DC sputtering

  7. Influence of residual oxygen-15-labeled carbon monoxide radioactivity on cerebral blood flow and oxygen extraction fraction in a dual-tracer autoradiographic method.

    Science.gov (United States)

    Iwanishi, Katsuhiro; Watabe, Hiroshi; Hayashi, Takuya; Miyake, Yoshinori; Minato, Kotaro; Iida, Hidehiro

    2009-06-01

    Cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO(2)), oxygen extraction fraction (OEF), and cerebral blood volume (CBV) are quantitatively measured with PET with (15)O gases. Kudomi et al. developed a dual tracer autoradiographic (DARG) protocol that enables the duration of a PET study to be shortened by sequentially administrating (15)O(2) and C(15)O(2) gases. In this protocol, before the sequential PET scan with (15)O(2) and C(15)O(2) gases ((15)O(2)-C(15)O(2) PET scan), a PET scan with C(15)O should be preceded to obtain CBV image. C(15)O has a high affinity for red blood cells and a very slow washout rate, and residual radioactivity from C(15)O might exist during a (15)O(2)-C(15)O(2) PET scan. As the current DARG method assumes no residual C(15)O radioactivity before scanning, we performed computer simulations to evaluate the influence of the residual C(15)O radioactivity on the accuracy of measured CBF and OEF values with DARG method and also proposed a subtraction technique to minimize the error due to the residual C(15)O radioactivity. In the simulation, normal and ischemic conditions were considered. The (15)O(2) and C(15)O(2) PET count curves with the residual C(15)O PET counts were generated by the arterial input function with the residual C(15)O radioactivity. The amounts of residual C(15)O radioactivity were varied by changing the interval between the C(15)O PET scan and (15)O(2)-C(15)O(2) PET scan, and the absolute inhaled radioactivity of the C(15)O gas. Using the simulated input functions and the PET counts, the CBF and OEF were computed by the DARG method. Furthermore, we evaluated a subtraction method that subtracts the influence of the C(15)O gas in the input function and PET counts. Our simulations revealed that the CBF and OEF values were underestimated by the residual C(15)O radioactivity. The magnitude of this underestimation depended on the amount of C(15)O radioactivity and the physiological conditions. This underestimation

  8. A new microbial screening method for the detection of antimicrobial residues in slaughter animals: The Nouws antibiotic test (NAT-screening)

    NARCIS (Netherlands)

    Pikkemaat, M.G.; Oostra-van Dijk, S.; Schouten, J.; Rapallini, M.; Egmond, van H.J.

    2008-01-01

    An improved microbial method for the screening of antimicrobial residues in slaughter animals has been developed. The Nouws antibiotic test (NAT-screening) is based on the analysis of renal pelvis fluid and comprises five test plates enabling group specific identification. The NAT-screening combines

  9. The Effect of Different Methods of Fermentation on the Detection of Milk Protein Residues in Retail Cheese by Enzyme-Linked Immunosorbent Assay (ELISA).

    Science.gov (United States)

    Ivens, Katherine O; Baumert, Joseph L; Hutkins, Robert L; Taylor, Steve L

    2017-11-01

    Milk and milk products are among the most important allergenic food ingredients, both in the United States and throughout the world; cheeses are among the most important of these milk products. Milk contains several major antigenic proteins, each with differing susceptibilities to proteolytic enzymes. The extent of proteolysis in cheese varies as a result of conditions during manufacture and ripening. Proteolysis has the potential to degrade antigenic and allergenic epitopes that are important for residue detection and elicitation of allergic reactions. Commercial enzyme-linked immunosorbent assays (ELISAs) are not currently validated for use in detecting residues in hydrolyzed or fermented food products. Eighteen retail cheeses produced using 5 different styles of fermentation were investigated for detectable milk protein residues with 4 commercial ELISA kits. Mozzarella, Swiss, Blue, Limburger, and Brie cheeses were assessed. The Neogen Veratox® Casein and Neogen Veratox® Total Milk kits were capable of detecting milk residues in most cheeses evaluated, including blue-veined cheeses that exhibit extensive proteolysis. The other 2 ELISA kits evaluated, r-Biopharm® Fast Casein and ELISA Systems™ Casein, can detect milk residues in cheeses other than blue-veined varieties. ELISA results cannot be quantitatively compared among kits. The quantitative reliability of ELISA results in detection of cheese residues is questionable, but some methods are sufficiently robust to use as a semi-quantitative indication of proper allergen control for the validation of cleaning programs in industry settings. Many commercially available enzyme-linked immunosorbent assays (ELISAs) are not validated for detection of allergenic residues in fermented or hydrolyzed products. This research seeks to determine if commercial milk ELISAs can detect milk residues in varieties of cheese that have undergone different styles of fermentation and different degrees of proteolysis. Only certain

  10. Study of the experimental parameters associated to the determination of residual macro stresses in stainless steel tubes through x-rays diffraction method

    International Nuclear Information System (INIS)

    Guimaraes, L.R.

    1990-01-01

    The basic principles related to the determination of residual macro stresses by X-rays diffractometry are present, whereas different techniques associated with the respective experimental errors are discussed. The residual stresses in two 304 L stainless steel tubes were measured using three models of diffractometers, Rigaku SG-8, Jeol JDX-11PA and Rigaku Strainflex. The measured values of stresses as well as the reproducibilities are examined. The suitability of peak location method, by fitting three data points to the parabolic function, is discussed through values of position and intensity obtained by two of the above diffractometers. (author)

  11. Study of the experimental parameters associated to the determination of residual macro stresses in stainless steel tubes, through x-ray diffraction method

    International Nuclear Information System (INIS)

    Guimaraes, L.R.

    1990-01-01

    The basic principles related to the determination of residual macro stresses by X-rays diffractometry are present, whereas different techniques associated with the respective experimental errors are discussed. The residual stresses in two 304 L stainless steel tubes were measured using three models of diffractometers, Rigaku SG-8, Jeol JDX-11PA and Rigaku Strainflex. The measured values of stresses as well as the reproducibilities are examined. The suitability of peak location method, by fitting three data points to the parabolic function, is discussed through values of position and intensity obtained by two of the above diffractometers. (author)

  12. Numerical and experimental evaluation of the residual stress relaxation and the influence zone due to application of the crack compliance method

    International Nuclear Information System (INIS)

    Sandoval-Pineda, J M; Garcia-Lira, J; Urriolagoitia-Sosa, G; Urriolagoitia-Calderon, G; Hernandez-Gomez, L H; Beltran-Fernandez, J A; RodrIguez-Martinez, R

    2009-01-01

    This paper presents the results concerning an evaluation of the crack compliance method. The research was focused on the relaxation caused by a cut induced to obtain the data required to calculate the residual stress field. The main objective in this research is to establish the optimum place to cut in a specimen that has suffered a failure and how extended is the zone of relaxed stresses. It has been recognized that a crack vanishes the beneficial or detrimental effects of the residual stress fields. This research has been performed in a numerical and experimental way, so results can be compared and FEM on this topic can be assessed.

  13. A balancing domain decomposition method by constraints for advection-diffusion problems

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Xuemin; Li, Jing

    2008-12-10

    The balancing domain decomposition methods by constraints are extended to solving nonsymmetric, positive definite linear systems resulting from the finite element discretization of advection-diffusion equations. A pre-conditioned GMRES iteration is used to solve a Schur complement system of equations for the subdomain interface variables. In the preconditioning step of each iteration, a partially sub-assembled finite element problem is solved. A convergence rate estimate for the GMRES iteration is established, under the condition that the diameters of subdomains are small enough. It is independent of the number of subdomains and grows only slowly with the subdomain problem size. Numerical experiments for several two-dimensional advection-diffusion problems illustrate the fast convergence of the proposed algorithm.

  14. Versions of the Collocation and Least Residuals Method for Solving Problems of Mathematical Physics in the Convex Quadrangular Domains

    Directory of Open Access Journals (Sweden)

    Vasily A. Belyaev

    2017-01-01

    Full Text Available The new versions of the collocations and least residuals (CLR method of high-order accuracy are proposed and implemented for the numerical solution of the boundary value problems for PDE in the convex quadrangular domains. Their implementation and numerical experiments are performed by the examples of solving the biharmonic and Poisson equations. The solution of the biharmonic equation is used for simulation of the stress-strain state of an isotropic plate under the action of the transverse load. Differential problems are projected into the space of fourth-degree polynomials by the CLR method. The boundary conditions for the approximate solution are put down exactly on the boundary of the computational domain. The versions of the CLR method are implemented on the grids, which are constructed by two different ways. In the first version, a “quasiregular” grid is constructed in the domain, the extreme lines of this grid coincide with the boundaries of the domain. In the second version, the domain is initially covered by a regular grid with rectangular cells. Herewith, the collocation and matching points that are situated outside the domain are used for approximation of the differential equations in the boundary cells that had been crossed by the boundary. In addition the “small” irregular triangular cells that had been cut off by the domain boundary from rectangular cells of the initial regular grid are joined to adjacent quadrangular cells. This technique allowed to essentially reduce the conditionality of the system of linear algebraic equations of the approximate problem in comparison with the case when small irregular cells together with other cells were used as independent ones for constructing an approximate solution of the problem. It is shown that the approximate solution of problems converges with high order and matches with high accuracy with the analytical solution of the test problems in the case of the known solution in

  15. Residuation theory

    CERN Document Server

    Blyth, T S; Sneddon, I N; Stark, M

    1972-01-01

    Residuation Theory aims to contribute to literature in the field of ordered algebraic structures, especially on the subject of residual mappings. The book is divided into three chapters. Chapter 1 focuses on ordered sets; directed sets; semilattices; lattices; and complete lattices. Chapter 2 tackles Baer rings; Baer semigroups; Foulis semigroups; residual mappings; the notion of involution; and Boolean algebras. Chapter 3 covers residuated groupoids and semigroups; group homomorphic and isotone homomorphic Boolean images of ordered semigroups; Dubreil-Jacotin and Brouwer semigroups; and loli

  16. A review of novel strategies of sample preparation for the determination of antibacterial residues in foodstuffs using liquid chromatography-based analytical methods

    International Nuclear Information System (INIS)

    Marazuela, M.D.; Bogialli, S.

    2009-01-01

    The determination of trace residues and contaminants in food has been of growing concern over the past few years. Residual antibacterials in food constitute a risk to human health, especially because they can contribute to the transmission of antibiotic-resistant pathogenic bacteria through the food chain. Therefore, to ensure food safety EU and USA regulatory agencies have established lists of forbidden or banned substances and tolerance levels for authorized veterinary drugs (e.g. antibacterials). In addition, the EU Commission Decision 2002/657/EC has set requirements about the performance of analytical methods for the determination of veterinary drug residues in food and feedstuffs. During the past years, the use of powerful mass spectrometric detectors in combination with innovative chromatographic technologies has solved many problems related to sensitivity and selectivity of this type of analysis. However sample preparation still remains as the bottleneck step, mainly in terms of analysis time and sources of error. This review covering research published between 2004 and 2008 intends to provide an update overview of the past five years, on recent trends in sample preparation for the determination of antibacterial residues in foods, making special emphasis in on-line, high-throughput, multi-class methods and including several applications in detail.

  17. Quarter-Sweep Iteration Concept on Conjugate Gradient Normal Residual Method via Second Order Quadrature - Finite Difference Schemes for Solving Fredholm Integro-Differential Equations

    International Nuclear Information System (INIS)

    Aruchunan, E.

    2015-01-01

    In this paper, we have examined the effectiveness of the quarter-sweep iteration concept on conjugate gradient normal residual (CGNR) iterative method by using composite Simpson's (CS) and finite difference (FD) discretization schemes in solving Fredholm integro-differential equations. For comparison purposes, Gauss- Seidel (GS) and the standard or full- and half-sweep CGNR methods namely FSCGNR and HSCGNR are also presented. To validate the efficacy of the proposed method, several analyses were carried out such as computational complexity and percentage reduction on the proposed and existing methods. (author)

  18. Evaluation of strength and residual stress in ceramic/metal joint by x-ray diffraction method

    International Nuclear Information System (INIS)

    Park, Young Chul; Han, Geum Jo; Hue, Sun Chul; Sin, In Su; Kang, Jae Wook

    1997-01-01

    Since the ceramic has outstanding properties of light weight, high abrasion resistance and heat resistance etc., compared with the metal, it has been examined in detail in order to apply for the structures such as gas turbine and turbo-charger etc., which require high strength and heat resistance. But it is not desirable to be used for the structural material since the ceramic is fragile, so the joint with the metal with abundant toughness has been studied. However, during the cooling process, the residual stress develops on the ceramic/metal joint by the difference in thermal expansion coefficient between two materials and this joint residual stress affects the bending strength significantly. Also in order to use the joint material as the structural material. the study about the fatigue of thermal cycle of actual use statement is necessary. Therefore, to ensure security and improvement of the bending strength of joint material, we studied the state of residual stress distribution to the high temperature-thermal cycle, and studied the effects of thermal cycle and state of residual stress distribution on the strength of joint material as well.

  19. A novel life cycle impact assessment method on biomass residue harvesting reckoning with loss of biomass productivity

    NARCIS (Netherlands)

    Wiloso, E.I.; Heijungs, R.; Huppes, G.

    2014-01-01

    Second generation bioenergy such as cellulosic bioethanol is expected to become commercially available in the near future. Large scale production of this bioenergy will require secure and continuous supplies of raw materials. One promising source of materials is biomass residues that currently

  20. The use of solid phase extraction method for analysis of residues of pesticides used in banana production in Costa Rica

    International Nuclear Information System (INIS)

    Castillo, L.E.; Ruepert, C.; Alfaro, A.R.; Solis, E.

    1999-01-01

    Different solid phase extraction devices were tested for the analysis of residues of eleven pesticides used in banana production in Costa Rica. The analysis was performed by using gas chromatograph equipped with NPD and ECD detectors. In general low recoveries and high variation coefficients were found for chlorothalonil, imazalil, terbufos and thiabendazole. For the other pesticides recoveries ranged between 60 and over 100%. (author)

  1. Analysis by the reductive-cleavage method of linkage positions in a polysaccharide containing 4-linked D-glucopyranosyluronic residues.

    Science.gov (United States)

    Vodonik, S A; Gray, G R

    1988-04-01

    The fate of 4-linked D-glucopyranosyluronic residues under reductive-cleavage conditions was investigated by using the Klebsiella aerogenes type 54 strain A3 capsular polysaccharide. Treatment of the fully methylated polysaccharide with triethylsilane and trimethylsilyl trifluoromethanesulfonate in dichloromethane, followed by in situ acetylation, yielded 1,5-anhydro-2,3,4,6-tetra-O-methyl-D-glucitol, 3,4-di-O-acetyl-1,5-anhydro-2,6-di-O-methyl-D-glucitol, and 3-O-acetyl-1,5-anhydro-2,4-di-O-methyl-L-fucitol, as expected, but the expected product of reductive cleavage of the 4-linked D-glucopyranosyluronic residue, namely, methyl 3-O-acetyl-2,6-anhydro-4,5-di-O-methyl-L-gulonate, was not observed. Instead, methyl 2-O-acetyl-3,6-anhydro-4,5-di-O-methyl-L-gulonate (6) was identified as the sole product of reductive cleavage of the 4-linked D-glucopyranosyluronic residue. That compound 6 arose as a result of rearrangement during reductive cleavage rather than by reductive cleavage of a 5-linked D-glucofuranosyluronic residue, was established by reductive cleavage of the fully methylated polysaccharide following reduction of its ester groups with either lithium aluminum hydride or lithium aluminum deuteride. The products of the latter reductive cleavage were the same as before, except for the absence of 6 and the presence of 4,6-di-O-acetyl-1,5-anhydro-2,3-di-O-methyl-D-glucitol, or its 6,6-dideuterio isomer. Although the reductive-cleavage technique is suitable for the direct analysis of polysaccharides containing 4-linked D-glucopyranosyluronic residues, it does not establish whether the uronic residue is a 4-linked pyranoside or a 5-linked furanoside. The expected product is, however, derived from the 4-linked D-glucopyranosyluronic residue after sequential methylation, reduction of its ester group and reductive cleavage.

  2. Evidence of non-extractable florfenicol residues: development and validation of a confirmatory method for total florfenicol content in kidney by UPLC-MS/MS.

    Science.gov (United States)

    Faulkner, Dermot; Cantley, Margaret; Walker, Matthew; Crooks, Steven; Kennedy, David; Elliott, Christopher

    2016-06-01

    The parent compound florfenicol (FF) is a broad-spectrum antibacterial compound licensed in the UK for use in cattle, pigs and the aquaculture industry. The analysis of porcine tissues in this study demonstrates that significant amounts of solvent non-extractable FF-related residues are present in incurred tissues (kidney and muscle) from treated animals. The results indicate that methods based on solvent extraction alone may carry a significant risk of reporting false-negative results. The use of a strong acid hydrolysis step prior to solvent extraction of tissue samples is necessary for an accurate estimate of the total tissue FF content. A robust and sensitive method for the determination of total FF residue content in kidney samples by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been developed and validated. This method covers the synthetic amphenicol drug FF and its metabolites, measured as the marker residue florfenicol amine (FFA) as per Commission Regulation (EU) No. 37/2010. Non-extractable and intermediate metabolites are converted to the hydrolysis product FFA, and then partitioned into ethyl acetate. Extracts are solvent exchanged prior to a dispersive solid-phase extraction step, then analysed using an alkaline reverse-phase gradient separation by UPLC-MS/MS. The method was validated around the maximum residue levels (MRLs) set out in Regulation (EU) No. 37/2010 for bovine kidney in accordance with Commission Decision No. 2002/657/EC. The following method performance characteristics were assessed during a single laboratory validation study: selectivity, specificity, sensitivity, linearity, matrix effects, accuracy and precision (decision limit (CCα) and detection capability (CCβ) were determined).

  3. Wide-Scope Screening Method for Multiclass Veterinary Drug Residues in Fish, Shrimp, and Eel Using Liquid Chromatography-Quadrupole High-Resolution Mass Spectrometry.

    Science.gov (United States)

    Turnipseed, Sherri B; Storey, Joseph M; Lohne, Jack J; Andersen, Wendy C; Burger, Robert; Johnson, Aaron S; Madson, Mark R

    2017-08-30

    A screening method for veterinary drug residues in fish, shrimp, and eel using LC with a high-resolution MS instrument has been developed and validated. The method was optimized for over 70 test compounds representing a variety of veterinary drug classes. Tissues were extracted by vortex mixing with acetonitrile acidified with 2% acetic acid and 0.2% p-toluenesulfonic acid. A centrifuged portion of the extract was passed through a novel solid phase extraction cartridge designed to remove interfering matrix components from tissue extracts. The eluent was then evaporated and reconstituted for analysis. Data were collected with a quadrupole-Orbitrap high-resolution mass spectrometer using both nontargeted and targeted acquisition methods. Residues were detected on the basis of the exact mass of the precursor and a product ion along with isotope pattern and retention time matching. Semiquantitative data analysis compared MS 1 signal to a one-point extracted matrix standard at a target testing level. The test compounds were detected and identified in salmon, tilapia, catfish, shrimp, and eel extracts fortified at the target testing levels. Fish dosed with selected analytes and aquaculture samples previously found to contain residues were also analyzed. The screening method can be expanded to monitor for an additional >260 veterinary drugs on the basis of exact mass measurements and retention times.

  4. A method to separate and quantify the effects of indentation size, residual stress and plastic damage when mapping properties using instrumented indentation

    International Nuclear Information System (INIS)

    Hou, X D; Jennett, N M

    2017-01-01

    Instrumented indentation is a convenient and increasingly rapid method of high resolution mapping of surface properties. There is, however, significant untapped potential for the quantification of these properties, which is only possible by solving a number of serious issues that affect the absolute values for mechanical properties obtained from small indentations. The three most pressing currently are the quantification of: the indentation size effect (ISE), residual stress, and pile-up and sink-in—which is itself affected by residual stress and ISE. Hardness based indentation mapping is unable to distinguish these effects. We describe a procedure that uses an elastic modulus as an internal reference and combines the information available from an indentation modulus map, a hardness map, and a determination of the ISE coefficient (using self-similar geometry indentation) to correct for the effects of stress, pile up and the indentation size effect, to leave a quantified map of plastic damage and grain refinement hardening in a surface. This procedure is used to map the residual stress in a cross-section of the machined surface of a previously stress free metal. The effect of surface grinding is compared to milling and is shown to cause different amounts of work hardening, increase in residual stress, and surface grain size reduction. The potential use of this procedure for mapping coatings in cross-section is discussed. (paper)

  5. A method to separate and quantify the effects of indentation size, residual stress and plastic damage when mapping properties using instrumented indentation

    Science.gov (United States)

    Hou, X. D.; Jennett, N. M.

    2017-11-01

    Instrumented indentation is a convenient and increasingly rapid method of high resolution mapping of surface properties. There is, however, significant untapped potential for the quantification of these properties, which is only possible by solving a number of serious issues that affect the absolute values for mechanical properties obtained from small indentations. The three most pressing currently are the quantification of: the indentation size effect (ISE), residual stress, and pile-up and sink-in—which is itself affected by residual stress and ISE. Hardness based indentation mapping is unable to distinguish these effects. We describe a procedure that uses an elastic modulus as an internal reference and combines the information available from an indentation modulus map, a hardness map, and a determination of the ISE coefficient (using self-similar geometry indentation) to correct for the effects of stress, pile up and the indentation size effect, to leave a quantified map of plastic damage and grain refinement hardening in a surface. This procedure is used to map the residual stress in a cross-section of the machined surface of a previously stress free metal. The effect of surface grinding is compared to milling and is shown to cause different amounts of work hardening, increase in residual stress, and surface grain size reduction. The potential use of this procedure for mapping coatings in cross-section is discussed.

  6. Validation of HPLC method of analysis of tetracycline residues in eggs and broiler meat and its application to a feeding trial.

    Science.gov (United States)

    De Ruyck, H; De Ridder, H; Van Renterghem, R; Van Wambeke, F

    1999-02-01

    HPLC with ion-pairing chromatography and diodearray detection at 355 nm was used to determine tetracycline antibiotics in eggs and broiler meat. The analytical methods were optimized and validated. The mean recovery values for oxytetracycline for eggs and for tetracycline for breast meat were 76%. The within-day precision ranged from 8.0 to 11.8% for oxytetracycline in eggs and from 6.1 to 15.5% for tetracycline in breast meat. The between-day precision was 4.8% and 5.0% respectively for oxytetracycline in eggs and tetracycline in breast meat. The limit of detection and the limit of quantitation for oxytetracycline in eggs were 2.2 and 13.0 ng/g respectively. These limits for tetracycline in breast meat were 10.5 and 20.9 ng/g respectively. Residue values of tetracycline antibiotics in eggs and broiler meat were determined after oral administration of medicated feed. Medicated feed with 840 mg/kg oxytetracycline was provided to laying hens for seven successive days. Two days after the administration was stopped, the mean oxytetracycline residue value in the eggs was already lower than the Maximum Residue Limit (MRL)-level and reached 118 ng/g. Broilers were supplied with medicated feed containing 480 mg/kg tetracycline for seven successive days. Four days after the administration was stopped, the mean tetracycline residue value in breast meat decreased below the MRL and was 86 ng/g.

  7. Residual stresses in material processing

    Science.gov (United States)

    Kozaczek, K. J.; Watkins, T. R.; Hubbard, C. R.; Wang, Xun-Li; Spooner, S.

    Material manufacturing processes often introduce residual stresses into the product. The residual stresses affect the properties of the material and often are detrimental. Therefore, the distribution and magnitude of residual stresses in the final product are usually an important factor in manufacturing process optimization or component life prediction. The present paper briefly discusses the causes of residual stresses. It then addresses the direct, nondestructive methods of residual stress measurement by X ray and neutron diffraction. Examples are presented to demonstrate the importance of residual stress measurement in machining and joining operations.

  8. EBER - development of evaluation methods for shipping and storage containers with an increased content of metallic residual materials

    International Nuclear Information System (INIS)

    Droste, B.; Voelzke, H.

    1995-01-01

    Containers which are manufactured using recycled metallic residual materials from decommissioned nuclear facilities must be designed in accordance with the requirements of transport, interim and ultimate storage of radioactive waste. When metallic residual materials are added to the melt in the manufacture of containers made of cast iron with nodular graphite (GGG 40), how the effect on and characteristics of materials are to be observed as well as the permissible limits. The influence on charcteristics of relevance to safety, such as fracture toughness and the types and magnitudes of defects in construction components are the most important factors. In BAM's 'EBER' project presented here, the studies concentrate on design-based safety against the mechanical effects of accidents. (orig./DG) [de

  9. Effect of Residual Stresses and Prediction of Possible Failure Mechanisms on Thermal Barrier Coating System by Finite Element Method

    Science.gov (United States)

    Ranjbar-Far, M.; Absi, J.; Mariaux, G.; Shahidi, S.

    2010-09-01

    This work is focused on the effect of the residual stresses resulting from the coating process and thermal cycling on the failure mechanisms within the thermal barrier coating (TBC) system. To reach this objective, we studied the effect of the substrate preheating and cooling rate on the coating process conditions. A new thermomechanical finite element model (FEM) considering a nonhomogeneous temperature distribution has been developed. In the results, we observed a critical stress corresponding to a low substrate temperature and high cooling rate during spraying of the top-coat material. Moreover, the analysis of the stress distribution after service shows that more critical stresses are obtained in the case where residual stresses are taken into account.

  10. A method of obtaining signal components of residual carrier signal with their power content and computer simulation

    Science.gov (United States)

    Kantak, Anil V.

    1993-01-01

    A novel algorithm to obtain all signal components of a residual carrier signal with any number of channels is presented. The phase modulation type may be NRZ-L or split phase (Manchester). The algorithm also provides a simple way to obtain the power contents of the signal components. Steps to recognize the signal components that influence the carrier tracking loop and the data tracking loop at the receiver are given. A computer program for numerical computation is also provided.

  11. A literature review of methods for handling solid residues arising from fuel dissolution in a nuclear fuel recycle plant

    International Nuclear Information System (INIS)

    Taylor, P.

    1990-06-01

    This report reviews the literature on the management of solid residues, principally Zircaloy fuel hulls, arising from fuel dissolution in nuclear fuel recycle plants. Emphasis is placed on information likely to be relevant to possible future recycling of CANDU fuel. The report was prepared as part of the supporting documentation for the evaluation of fuel-waste treatment and disposal options in the Canadian Nuclear Fuel Waste Management Program

  12. Determination of residual moisture in lyophilized protein pharmaceuticals using a rapid and non-invasive method: near infrared spectroscopy.

    Science.gov (United States)

    Lin, Tanya P; Hsu, Chung C

    2002-01-01

    This study examined the application of near-infrared (NIR) spectroscopy to analyze residual moisture in lyophilized protein pharmaceuticals sealed in glass vials. We demonstrated that NIR was able to determine residual moisture in five marketed and clinical products with the same precision as Karl Fischer titration. We further investigated how changes in product configuration and protein formulation affected NIR measurement accuracy using a lyophilized monoclonal antibody rhuMAb E25 containing 1% to 5% residual moisture. The results indicated that the lyophilized cake porosity and dimensions had no effect on NIR measurement when the cake height and diameter exceeded the NIR penetration depth. In addition, changing the buffer and surfactant concentrations in the formulation did not affect moisture determination by NIR. However, doubling or halving the concentration of a disaccharide, which was used as a lyoprotectant, caused significant deviation between the NIR and Karl Fischer data because the NIR absorbance of the disaccharide overlapped with the moisture signal. Furthermore, complete removal of the disaccharide resulted in alteration of the protein NIR spectra, suggesting that NIR may be used to evaluate solid-state protein structure. The disaccharide concentration must be kept constant in this formulation to obtain accurate moisture results by NIR.

  13. Development of a multi-residue screening method for the determination of pesticides in cereals and dry animal feed using gas chromatography-triple quadrupole tandem mass spectrometry.

    Science.gov (United States)

    Walorczyk, Stanisław

    2007-09-21

    A multi-residue screening method for simultaneous analysis of 122 gas chromatography amenable pesticides in dry matrices such as cereal grain and certain feedingstuffs was developed. The method entails a simple extraction of re-hydrated sample with acetonitrile followed by a dispersive solid phase extraction (dispersive-SPE) clean-up step prior to the final determination by gas chromatography/triple quadrupole tandem mass spectrometry (GC-MS/MS). Due to complexity of analyzed matrices, two MS/MS transitions were set for each pesticide to eliminate the need for re-analysis of potentially positive samples, and provide unequivocal identification of detected pesticides in accordance with recent guidelines, in a single analytical run. Thus, in the developed GC-MS/MS acquisition method, a total of 216 different multiple reactions monitoring (MRM) transitions were monitored in one set of experimental conditions. To evaluate performance of the method, validation experiments were carried out on wheat grain at three spiking levels (0.01, 0.02 and 0.05 mg kg(-1)). Additional recovery tests at 0.05 mg kg(-1) were carried out on several other matrices. The recoveries ranged between 73 and 129% with associated relative standard deviations between 1 and 29% for the majority of pesticides. Limits of detection were less or equal to 0.01 mg kg(-1) for approximately 68% of pesticides. The applicability of the proposed method to detect and quantify pesticide residues has been demonstrated in the analysis of 136 real samples. Additionally, the method was favorably compared with an acetone extraction method (accepted as a reference method by some of European and U.S. authorities) in the analysis of real samples known to contain pesticide residues.

  14. A multi-residue method for 17 anticoccidial drugs and ractopamine in animal tissues by liquid chromatography-tandem mass spectrometry and time-of-flight mass spectrometry.

    Science.gov (United States)

    Matus, Johanna L; Boison, Joe O

    2016-05-01

    A new and sensitive multi-residue liquid chromatography-tandem mass spectrometry (LC-MS/MS) and liquid chromatography-quadrupole time-of-flight-mass spectrometry (LC-QToF-MS) method was developed and validated for the determination and confirmation of residues of 17 anticoccidials, plus free ractopamine in poultry muscle and liver, and bovine muscle, liver, and kidney tissues. The 17 anticoccidials are lasalocid, halofuginone, narasin, monensin, semduramicin, ethopabate, robenidine, buquinolate, toltrazuril as its sulfone metabolite, maduramicin, salinomycin, diclazuril, amprolium, decoquinate, dinitolmide, clopidol, and the nicarbazin metabolite DNC (N,N1-bis(4-nitrophenyl)urea). The analytes were extracted and cleaned up within a 3-hour period by simply extracting the analytes into a solvent mixture with salts followed by centrifugation, dilution, and filtration. The validated method was used in a pilot study for the analysis of 173 samples that included quail liver, bovine kidney, liver, muscle, and horse muscle. The predominant residues found in this study were monensin, ractopamine, and lasalocid. The results of this pilot study showed that this new method is applicable to real samples, and is fit for use in a regulatory testing programme. © 2016 Her Majesty the Queen in Right of Canada. Drug Testing and Analysis. © 2016 John Wiley & Sons, Ltd. © 2016 Her Majesty the Queen in Right of Canada. Drug Testing and Analysis. © 2016 John Wiley & Sons, Ltd.

  15. Development and validation of a high-performance liquid chromatography method for determination of ractopamine residue in pork samples by solid phase extraction and pre-column derivatization.

    Science.gov (United States)

    Ding, Guanglong; Li, Deguang; Qin, Jiao; Zhu, Juanli; Wang, Baitao; Geng, Qianqian; Guo, Mingcheng; Punyapitak, Darunee; Cao, Yongsong

    2015-08-01

    Ractopamine (RAC) has been approved as a feed additive for swine, cattle or turkey, and is likely to have residue in edible animal products and may pose a potential risk for consumer health. Therefore, it is essential to establish a method to detect the residue of RAC in animal products. This work presents a rapid and sensitive HPLC method for the determination of RAC in pork samples with pre-column derivatization. The RAC derivative was separated on a kromasil C18 column and detected at 284nm with a UV detector. The detection capability (CCβ) was 0.078μgg(-1) and the linearity was established over the concentration range of 0.15-100.0μgg(-1). The overall mean recovery in spike range of 0.2μgg(-1) to 100μgg(-1) was 89.9% with the overall mean relative standard deviation of 4.1%. This method can be used for the quantification of RAC in pork samples and help to establish adequate monitoring of the residue of RAC. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Development of a Method for the Analysis of Multiclass Antibiotic Residues in Milk Using QuEChERS and Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Wang, Yuan-long; Liu, Zhen-min; Ren, Jing; Guo, Ben-heng

    2015-08-01

    A precise and simplified method of sample preparation for the simultaneous quantification of the antibiotics β-lactam, macrolide, tetracycline, sulfonamide, and quinolone in bovine milk was developed. The central composite design of response surface methodology was used to design and optimize the method for the determination of six different antibiotic residues in milk. The recovery of each antibiotic was studied using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. Octadecylsilane (C18), primary secondary amine (PSA), and sodium acetate (Na acetate) were the main factors affecting the recovery of each antibiotic. After optimization, the maximum predicted recovery rate was 84.18% for erythromycin under the optimized conditions of 101.20 mg C18, 52.00 mg PSA, and 1.01 g Na acetate. The recovery rates of the five other antibiotic residues ranged from 86.09% to 115.99%. The results suggested that modified QuEChERS could effectively be implemented in the analysis of antibiotic residues in milk.

  17. Determination of cyflumetofen residue in water, soil, and fruits by modified quick, easy, cheap, effective, rugged, and safe method coupled to gas chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Li, Minmin; Liu, Xingang; Dong, Fengshou; Xu, Jun; Qin, Dongmei; Zheng, Yongquan

    2012-10-01

    A new, highly sensitive, and selective method was developed for the determination of the cyflumetofen residue in water, soil, and fruits by using gas chromatography quadruple mass spectrometry. The target compound was extracted using acetonitrile and then cleaned up using dispersive solid-phase extraction with primary and secondary amine and graphitized carbon black, and optionally by a freezing-out cleanup step. The matrix-matched standards gave satisfactory recoveries and relative standard deviation values in different matrices at three fortified levels (0.05, 0.5, and 1.0 mg kg(-1) ). The overall average recoveries for this method in water, soil, and all fruits matrix at three fortified levels ranged from 76.3 to 101.5% with relative standard deviations in the range of 1.2-11.8% (n = 5). The calculated limits of detection and quantification were typically below 0.005 and 0.015 μg kg(-1), which were much lower than the maximum residue levels established by Japanese Positive List. This study provides a theoretical basis for China to draw up maximum residue level and analytical method for cyflumetofen acaricide in different fruits. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. [Determination of 51 carbamate pesticide residues in vegetables by liquid chromatography-tandem mass spectrometry based on optimization of QuEChERS sample preparation method].

    Science.gov (United States)

    Wang, Lianzhu; Zhou, Yu; Huang, Xiaoyan; Wang, Ruilong; Lin, Zixu; Chen, Yong; Wang, Dengfei; Lin, Dejuan; Xu, Dunming

    2013-12-01

    The raw extracts of six vegetables (tomato, green bean, shallot, broccoli, ginger and carrot) were analyzed using gas chromatography-mass spectrometry (GC-MS) in full scan mode combined with NIST library search to confirm main matrix compounds. The effects of cleanup and adsorption mechanisms of primary secondary amine (PSA) , octadecylsilane (C18) and PSA + C18 on co-extractives were studied by the weight of evaporation residue for extracts before and after cleanup. The suitability of the two versions of QuEChERS method for sample preparation was evaluated for the extraction of 51 carbamate pesticides in the six vegetables. One of the QuEChERS methods was the original un-buffered method published in 2003, and the other was AOAC Official Method 2007.01 using acetate buffer. As a result, the best effects were obtained from using the combination of C18 and PSA for extract cleanup in vegetables. The acetate-buffered version was suitable for the determination of all pesticides except dioxacarb. Un-buffered QuEChERS method gave satisfactory results for determining dioxacarb. Based on these results, the suitable QuEChERS sample preparation method and liquid chromatography-positive electrospray ionization-tandem mass spectrometry under the optimized conditions were applied to determine the 51 carbamate pesticide residues in six vegetables. The analytes were quantified by matrix-matched standard solution. The recoveries at three levels of 10, 20 and 100 microg/kg spiked in six vegetables ranged from 58.4% to 126% with the relative standard deviations of 3.3%-26%. The limits of quantification (LOQ, S/N > or = 10) were 0.2-10 microg/kg except that the LOQs of cartap and thiofanox were 50 microg/kg. The method is highly efficient, sensitive and suitable for monitoring the 51 carbamate pesticide residues in vegetables.

  19. Residue processing

    Energy Technology Data Exchange (ETDEWEB)

    Gieg, W.; Rank, V.

    1942-10-15

    In the first stage of coal hydrogenation, the liquid phase, light and heavy oils were produced; the latter containing the nonliquefied parts of the coal, the coal ash, and the catalyst substances. It was the problem of residue processing to extract from these so-called let-down oils that which could be used as pasting oils for the coal. The object was to obtain a maximum oil extraction and a complete removal of the solids, because of the latter were returned to the process they would needlessly burden the reaction space. Separation of solids in residue processing could be accomplished by filtration, centrifugation, extraction, distillation, or low-temperature carbonization (L.T.C.). Filtration or centrifugation was most suitable since a maximum oil yield could be expected from it, since only a small portion of the let-down oil contained in the filtration or centrifugation residue had to be thermally treated. The most satisfactory centrifuge at this time was the Laval, which delivered liquid centrifuge residue and centrifuge oil continuously. By comparison, the semi-continuous centrifuges delivered plastic residues which were difficult to handle. Various apparatus such as the spiral screw kiln and the ball kiln were used for low-temperature carbonization of centrifuge residues. Both were based on the idea of carbonization in thin layers. Efforts were also being made to produce electrode carbon and briquette binder as by-products of the liquid coal phase.

  20. Development of an efficient method for multi residue analysis of 160 pesticides in herbal plant by ethyl acetate hexane mixture with direct injection to GC-MS/MS.

    Science.gov (United States)

    Taha, Sherif M; Gadalla, Sohair A

    2017-11-01

    A simple and efficient multi residue method was developed, for the analysis of 160 pesticides by GC-MS/MS in herbal plants. The developed method employs pesticide residue extraction by EtAC/ n. hexane (6:4) with a cleanup step using florisil/ PSA mixture. The optimized conditions have resulted in lower co-extracted matrix components than those extracted using EtAC or MeCN (QuEChERS method), according to FTIR and full scan GC/MS analyses. In addition, the developed method (EtAC/ Hexane) eliminates the evaporation step that is usually performed when using MeCN as an extraction solvent prior to the GC-MS/MS injection. The developed method was fully validated on chamomile, based on SANTE/11945/2015 guidelines. Where, intraday recoveries were estimated at three concentration levels of 10, 50 and 250μgkg -1 . However, interday recoveries have also been carried out, at 250μgkg -1 . In addition, intraday recoveries were estimated for two other herbal plants (thyme and marjoram), at 250μgkg -1 . Three point calibration mixtures were prepared in ethyl acetate solvent and in the blank extracts of chamomile, thyme, and marjoram, in order to check the linearity and matrix effect. The average recoveries for most of the studied pesticides ranged from 70% to 100% at 50 and 250μgkg -1 with relative standard deviations below 20%. The validated method was successfully applied for determination of pesticide residues in 20 herb samples, collected from the Egyptian market. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Identification of family-specific residue packing motifs and their use for structure-based protein function prediction: I. Method development

    Science.gov (United States)

    Bandyopadhyay, Deepak; Huan, Jun; Prins, Jan; Snoeyink, Jack; Wang, Wei; Tropsha, Alexander

    2009-11-01

    Protein function prediction is one of the central problems in computational biology. We present a novel automated protein structure-based function prediction method using libraries of local residue packing patterns that are common to most proteins in a known functional family. Critical to this approach is the representation of a protein structure as a graph where residue vertices (residue name used as a vertex label) are connected by geometrical proximity edges. The approach employs two steps. First, it uses a fast subgraph mining algorithm to find all occurrences of family-specific labeled subgraphs for all well characterized protein structural and functional families. Second, it queries a new structure for occurrences of a set of motifs characteristic of a known family, using a graph index to speed up Ullman's subgraph isomorphism algorithm. The confidence of function inference from structure depends on the number of family-specific motifs found in the query structure compared with their distribution in a large non-redundant database of proteins. This method can assign a new structure to a specific functional family in cases where sequence alignments, sequence patterns, structural superposition and active site templates fail to provide accurate annotation.

  2. Rapid analytical method for the determination of pesticide residues in sunflower seeds based on focused microwave-assisted Soxhlet extraction prior to gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Prados-Rosales, R C; Luque García, J L; Luque de Castro, M D

    2003-04-18

    A rapid analytical method for determination of organochlorine pesticide residues in sunflower seeds based on focused microwave-assisted Soxhlet extraction has been developed. The main factors affecting the extraction efficiency--namely microwave power, irradiation time, volume of extractant and number of cycles--were optimized by a two-level factorial fractional design. After extraction, a liquid-liquid extraction and a clean-up step including the use of Florisil macrocolumns were required prior to injection of the extracts into the chromatograph in order to isolate the pesticide residues from the lipid fraction of the original extract. The MS-MS ion preparation mode was selected due to the high sensitivity and selectivity it provides. Seed samples were used collected near a crop subjected to aerial pesticide application. Residues of hexachlorocyclohexane isomers and endosulfan were found in the seeds although they were not subjected to pesticide application, thus showing the spray-drift contamination. The validation of the proposed approach was carried out by comparison with the ISO 659-1988 reference extraction method obtaining similar, or even better efficiencies by the proposed approach.

  3. Validation of QuEChERS based method for determination of fenitrothion residues in tomatoes by gas chromatography-flame photometric detector: Decline pattern and risk assessment.

    Science.gov (United States)

    Malhat, Farag; Boulangé, Julien; Abdelraheem, Ehab; Abd Allah, Osama; Abd El-Hamid, Rania; Abd El-Salam, Shokr

    2017-08-15

    A simple and rapid gas chromatography with flame photometric detector (GC-FPD) determination method was developed to detect residue levels and investigate the dissipation pattern and safe use of fenitrothion in tomatoes. A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) using an ethyl acetate-based extraction, followed by a dispersive solid-phase extraction (d-SPE) with primary-secondary amine (PSA) and graphite carbon black (GCB) for clean up, was applied prior to GC-FPD analysis. The method showed satisfactory linearity, recovery and precision. The limits of detection (LOD) and quantification (LOQ) were 0.005 and 0.01mg/kg, respectively. The residue levels of fenitrothion were best described by first order kinetics with a half-life of 2.2days in tomatoes. The potential health risks posed by fenitrothion were not significant, based on supervised residue trial data. The current findings could provide guidance for safe and reasonable use of fenitrothion in tomatoes and prevent health problems to consumers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Bithionol residue analysis in animal-derived food products by an effective and rugged extraction method coupled with liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zheng, Weijia; Park, Jin-A; Abd El-Aty, A M; Kim, Seong-Kwan; Cho, Sang-Hyun; Choi, Jeong-Min; Yi, Hee; Cho, Soo-Min; El-Banna, H A; Shim, Jae-Han; Chang, Byung-Joon; Wang, Jing; Kim, Jin-Suk; Shin, Ho-Chul

    2017-10-01

    Herein, we developed a simple analytical procedure for the quantitation of bithionol residues in animal-derived food products such as porcine muscle, eggs, milk, eel, flatfish, and shrimp using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction method coupled with liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI + /MS-MS). Samples were extracted with 0.1% solution of formic acid in acetonitrile and the extract was purified using a C18 sorbent. Separation was performed on a Waters XBridge™ C18 reversed-phase analytical column using 0.1% solution of formic acid/acetonitrile as the mobile phase. Six-point matrix-matched calibration indicated good linearity, with the calculated coefficients of determination (R 2 ) being≥0.9813. Intra- and inter-day recoveries (determined at spiking levels equivalent to 1×and 2×the limit of quantitation (0.25μg/kg)) ranged between 80.0 and 94.0%, with the corresponding relative standard deviations (RSDs) being≤8.2%. The developed experimental protocol was applied to different samples purchased from local markets in Seoul, which were tested negative for bithionol residues. In conclusion, the proposed method proved to be versatile and precise, being ideally suited for the routine detection of bithionol residues in animal-derived food products with various protein and fat contents. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Analysis of Veterinary Drug and Pesticide Residues Using the Ethyl Acetate Multiclass/Multiresidue Method in Milk by Liquid Chromatography-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Husniye Imamoglu

    2016-01-01

    Full Text Available A rapid and simple multiclass, ethyl acetate (EtOAc multiresidue method based on liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS detection was developed for the determination and quantification of 26 veterinary drugs and 187 total pesticide residues in milk. Sample preparation was a simple procedure based on liquid–liquid extraction with ethyl acetate containing 0.1% acetic acid, followed by centrifugation and evaporation of the supernatant. The residue was dissolved in ethyl acetate with 0.1% acetic acid and centrifuged prior to LC-MS/MS analysis. Chromatographic separation of analytes was performed on an Inertsil X-Terra C18 column with acetic acid in methanol and water gradient. The repeatability and reproducibility were in the range of 2 to 13% and 6 to 16%, respectively. The average recoveries ranged from 75 to 120% with the RSD (n=18. The developed method was validated according to the criteria set in Commission Decision 2002/657/EC and SANTE/11945/2015. The validated methodology represents a fast and cheap alternative for the simultaneous analysis of veterinary drug and pesticide residues which can be easily extended to other compounds and matrices.

  6. Fluorescence histochemistry of peptide hormone-producing cells: observations on the phenanthrenequinone method for the demonstration of arginine residues.

    Science.gov (United States)

    Sundler, F; Håkanson, R

    1978-07-12

    Phenanthrenequinone is a sensitive and specific fluorescence histochemical reagent for monosubstituted guanidines. It is probable that it selectively demonstrates the guanidino group of arginine residues of proteins and peptides. Phenanthrenequinone induces moderate to intense fluorescence in gastric chief cells, parenchymal cells of the pancreas, and certain peptide hormone-producing cell types such as the GH cells of the adenohypophysis and the glucagon cells of the pancreatic islets. Similar fluorescence spectra were obtained from an arginine-containing peptide in a histochemical model and from the GH cells of the adenohypophysis following exposure to phenanthrenequinone. We conclude that the cells demonstrated with this reagent store peptides or proteins rich in arginine.

  7. Residual stress measurments of chromium films by x-ray diffraction, the sin/sup 2/psi method

    Energy Technology Data Exchange (ETDEWEB)

    Wong, S.M.

    1978-01-01

    Residual stresses on chromium films vacuum deposited by electron beam on beryllium substrates were measured by x-ray diffraction. The minute peak shift of the diffraction profile reveals the presence of strain, hence stress. Shift detection was made possible by fitting experimental data to a modified Lorentz function and then subjecting the fit to a regression analysis. Computer aid was utilized extensively. Stresses, both tensile and compressive, and of magnitude between 10/sup 9/ to 10/sup 10/ dynes cm/sup -2/ were found for substrate temperatures in the range of 300 to 550/sup 0/C.

  8. Screening for tetracycline residues in food products of animal origin in the State of Kuwait using Charm II radio-immunoassay and LC/MS/MS methods.

    Science.gov (United States)

    Al-Mazeedi, Hani M; Abbas, Alaa B; Alomirah, Hussam F; Al-Jouhar, Wafaa Y; Al-Mufty, Siham A; Ezzelregal, Mohamed M; Al-Owaish, Rashed A

    2010-03-01

    This study surveyed tetracycline residues in foods marketed in Kuwait using various techniques to determine their prevalence above the threshold level. A total of 1517 locally produced and imported food samples of animal origin were collected for analyses, comprising dairy products, eggs and tissue samples (meat, poultry and fish) to give a representative picture of the current use and/or misuse of the drug in Kuwait. Screening was carried out using the Charm II test for tetracycline residues. Positive and suspect positive samples were confirmed by LC/MS/MS. Negative and positive controls, in triplicate, were applied to each method and showed 80-100% agreement. The results showed that 100% of tested eggs, meat, fish, ice cream and cheese were within the limit, while 5% of poultry and 18% of milk samples were above the permitted limit.

  9. A novel method to determine residual detergent in biological samples post endotoxin reduction treatment and evaluation of strategies for subsequent detergent removal.

    Science.gov (United States)

    London, Anne Serdakowski; Japutra, Chietara; Planck, Kyle; Lihon, Michael; Nguyen, Andrew Anh

    2016-08-01

    Endotoxin removal using detergent washes and extractions are well-established, efficient, and cost-effective methods; however, removing residual detergent post treatment has been shown to be a challenge. In this communication, we show a simple and fast method for determining the detergent concentration in a protein solution post treatment and highlight strategies for detergent removal to achieve levels below the critical micelle concentration (CMC), the minimum concentration at which detergent micelles form. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Development of a multi-residue analytical method, based on liquid chromatography-tandem mass spectrometry, for the simultaneous determination of 46 micro-contaminants in aqueous samples.

    Science.gov (United States)

    Nödler, Karsten; Licha, Tobias; Bester, Kai; Sauter, Martin

    2010-10-15

    A multi-residue analytical method based on high-performance liquid chromatographic separation, electrospray ionization with tandem mass spectrometric detection (HPLC/MS-MS) was developed for the simultaneous analysis of 46 basic, neutral and acidic compounds covering a wide range of polarity (logK(OW)MQL) in surface and seawater ranged from 1.2 to 28 ng/L, in wastewater from 5.0 to 160 ng/L, respectively. In order to demonstrate the applicability of the method, river water, treated wastewater and seawater were analyzed. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Carbon stock estimates for forests in the Castilla y Leon region, Spain. A GIS based method for evaluating spatial distribution of residual biomass for bio-energy

    Energy Technology Data Exchange (ETDEWEB)

    Gil, Maria Victoria; Blanco, Daniel; Carballo, Maria Teresa; Calvo, Luis Fernando [Chemical Engineering, Institute of Natural Resources, University of Leon, Avenida de Portugal, 41, 24071 Leon (Spain)

    2011-01-15

    Analysis of aboveground biomass and carbon stocks (as equivalent CO{sub 2}) was performed in the Castilla y Leon region, Spain. Data from the second and third Spanish Forest Inventories (1996 and 2006) were used. Total aboveground biomass was calculated using allometric biomass equations and biomass expansion factors (BEF), the first method giving higher values. Forests of Castilla y Leon stored 77,051,308 Mg of biomass, with a mean of 8.18 Mg ha{sup -1}, in 1996 and 135,531,737 Mg of biomass, with a mean of 14.4 Mg ha{sup -1}, in 2006. The total equivalent CO{sub 2} in this region's forests increased 9,608,824 Mg year{sup -1} between 1996 and 2006. In relation to the Kyoto Protocol, the Castilla y Leon forests have sequestered 3 million tons of CO{sub 2} per year, which represents 6.4% of the total regional emission of CO{sub 2}. A Geographic Information System (GIS) based method was also used to assess the geographic distribution of residual forest biomass for bio-energy in the region. The forest statistics data on area of each species were used. The fraction of vegetation cover, land slope and protected areas were also considered. The residual forest biomass in Castilla y Leon was 1,464,991 Mg year{sup -1}, or 1.90% of the total aboveground biomass in 1996. The residual forest biomass was concentrated in specific zones of the Castilla y Leon region, suitable for the location of industries that utilize biomass as energy source. The energy potential of the residual forest biomass in the Castilla y Leon region is 7350 million MJ per year. (author)

  12. Interaction of residue tetracycline hydrochloride in milk with β-galactosidase protein by multi-spectrum methods and molecular docking

    Science.gov (United States)

    Gao, Xin; Bi, Hongna; Zuo, Huijun; Jia, Jingjing; Tang, Lin

    2017-08-01

    The purpose of this study was to explore the effect of residue tetracycline hydrochloride (TCH) in milk on molecular structure and activity of β-Gal. Inhibition kinetics assay showed the TCH inhibited β-Gal activity reversibly in a competitive manner. In addition, differences in the activity of β-Gal in the absence and presence of TCH as a function of pH and temperature were found although the optimum pH and temperature of β-Gal remained similar. Fluorescence experiment results showed that TCH effectively quenched the intrinsic fluorescence of β-Gal via static quenching. Thermodynamic parameters delineated the major roles of electrostatic forces played between β-Gal and TCH. Additionally, synchronous fluorescence and circular dichroism spectra (CD spectra) results indicated the secondary structure of β-Gal was changed due to the formation of β-Gal-TCH complexes. The molecular docking further revealed that TCH interacted with some amino acid residues of β-Gal, affecting the active site of the enzyme and thus leading to change in enzyme activity. These alterations in conformation and activity of β-Gal should be taken into consideration while using β-Gal for producing oligosaccharide prebiotics on dairy industries.

  13. Analysis of Margin Index as a Method for Predicting Residual Disease After Breast-Conserving Surgery in a European Cancer Center.

    LENUS (Irish Health Repository)

    Bolger, Jarlath C

    2011-06-03

    INTRODUCTION: Breast-conserving surgery (BCS), followed by appropriate adjuvant therapies is established as a standard treatment option for women with early-stage invasive breast cancers. A number of factors have been shown to correlate with local and regional disease recurrence. Although margin status is a strong predictor of disease recurrence, consensus is yet to be established on the optimum margin necessary. Margenthaler et al. recently proposed the use of a "margin index," combining tumor size and margin status as a predictor of residual disease after BCS. We applied this new predictive tool to a population of patients with primary breast cancer who presented to a symptomatic breast unit to determine its suitability in predicting those who require reexcision surgery. METHODS: Retrospective analysis of our breast cancer database from January 1, 2000 to June 30, 2010 was performed, including all patients who underwent BCS. Of 531 patients who underwent BCS, 27.1% (144\\/531) required further reexcision procedures, and 55 were eligible for inclusion in the study. Margin index was calculated as: margin index = closest margin (mm)\\/tumor size (mm) × 100, with index >5 considered optimum. RESULTS: Of the 55 patients included, 31% (17\\/55) had residual disease. Fisher\\'s exact test showed margin index not to be a significant predictor of residual disease on reexcision specimen (P = 0.57). Of note, a significantly higher proportion of our patients presented with T2\\/3 tumors (60% vs. 38%). CONCLUSIONS: Although an apparently elegant tool for predicting residual disease after BCS, we have shown that it is not applicable to a symptomatic breast unit in Ireland.

  14. Analysis of margin index as a method for predicting residual disease after breast-conserving surgery in a European cancer center.

    LENUS (Irish Health Repository)

    Bolger, Jarlath C

    2012-02-01

    INTRODUCTION: Breast-conserving surgery (BCS), followed by appropriate adjuvant therapies is established as a standard treatment option for women with early-stage invasive breast cancers. A number of factors have been shown to correlate with local and regional disease recurrence. Although margin status is a strong predictor of disease recurrence, consensus is yet to be established on the optimum margin necessary. Margenthaler et al. recently proposed the use of a "margin index," combining tumor size and margin status as a predictor of residual disease after BCS. We applied this new predictive tool to a population of patients with primary breast cancer who presented to a symptomatic breast unit to determine its suitability in predicting those who require reexcision surgery. METHODS: Retrospective analysis of our breast cancer database from January 1, 2000 to June 30, 2010 was performed, including all patients who underwent BCS. Of 531 patients who underwent BCS, 27.1% (144\\/531) required further reexcision procedures, and 55 were eligible for inclusion in the study. Margin index was calculated as: margin index = closest margin (mm)\\/tumor size (mm) x 100, with index >5 considered optimum. RESULTS: Of the 55 patients included, 31% (17\\/55) had residual disease. Fisher\\'s exact test showed margin index not to be a significant predictor of residual disease on reexcision specimen (P = 0.57). Of note, a significantly higher proportion of our patients presented with T2\\/3 tumors (60% vs. 38%). CONCLUSIONS: Although an apparently elegant tool for predicting residual disease after BCS, we have shown that it is not applicable to a symptomatic breast unit in Ireland.

  15. Oscillations

    Directory of Open Access Journals (Sweden)

    Qinghua Wu

    2015-01-01

    equivalent to the GMRES method proposed by Olver (2009. Moreover, the simpler GMRES does not require upper Hessenberg matrix factorization, which leads to much simpler program and requires less work. Numerical experiments are conducted to illustrate the performance of the new method and show that in some cases the simpler GMRES method could achieve higher accuracy than GMRES.

  16. Residual risk

    African Journals Online (AJOL)

    ing the residual risk of transmission of HIV by blood transfusion. An epidemiological approach assumed that all HIV infections detected serologically in first-time donors were pre-existing or prevalent infections, and that all infections detected in repeat blood donors were new or incident infections. During 1986 - 1987,0,012%.

  17. Autoclave sterilization of instruments used on women with cervical neoplasia is an effective method of eradicating residual human papillomavirus DNA: a polymerase chain reaction-based evaluation.

    Science.gov (United States)

    Estes, Jacob M; Kirby, Tyler O; Huh, Warner K

    2007-01-01

    To determine whether autoclave sterilization eradicates human papillomavirus (HPV) DNA on specula and instruments used to treat women with cervical neoplasia. Specula and instruments used in two referral colposcopy clinics were evaluated to determine the PGMY9/11 primer system's ability to amplify residual HPV DNA. Each speculum and instrument was sampled with a Dacron swab and stored in PreservCyt solution (Cytyc Corporation, Marlborough, MA) at 4 degrees C. DNA amplification was performed under standard conditions with appropriate controls followed by HPV typing using the reverse line blot test (Roche Molecular Systems, Alameda, CA). Once validated, the same polymerase chain reaction method was used on autoclave-sterilized specula and biopsy instruments and heated glass bead- and Cidex bath (Johnson & Johnson, New Brunswick, NJ)-sterilized instruments. All results, with appropriate positive and negative controls, were confirmed in triplicate. A total of 140 instruments (70 used and 70 autoclaved) were sampled for residual HPV DNA. Five samples in the contaminated specula arm were excluded from analysis secondary to insufficient sampling. Of the remaining samples, 52.3% (34/65) of contaminated instruments-both specula and biopsy instruments-had detectable HPV DNA. Fifty-five percent of contaminated biopsy instruments (11/20) were positive and 51.1% of contaminated specula (23/45) were positive. All 70 autoclaved samples (50 specula and 20 biopsy instruments) were negative for residual HPV DNA or beta-globin. One instrument in the glass bead and Cidex group that was presumed sterile was positive for HPV 16 DNA. The PGMY9/11 primer system is an effective method to detect residual HPV DNA. Autoclave sterilization appears to eradicate HPV DNA to levels undetectable with this sensitive assay, whereas heated glass beads followed by Cidex bath appears to be inadequate methods. These results suggest that autoclave sterilization is effective when using nondisposable

  18. Development and validation of a stability-indicating gas chromatographic method for quality control of residual solvents in blonanserin: a novel atypical antipsychotic agent.

    Science.gov (United States)

    Peng, Ming; Liu, Jin; Lu, Dan; Yang, Yong-Jian

    2012-09-01

    Blonanserin is a novel atypical antipsychotic agent for the treatment of schizophrenia. Ethyl alcohol, isopropyl alcohol and toluene are utilized in the synthesis route of this bulk drug. A new validated gas chromatographic (GC) method for the simultaneous determination of residual solvents in blonanserin is described in this paper. Blonanserin was dissolved in N, N-dimethylformamide to make a sample solution that was directly injected into a DB-624 column. A postrun oven temperature at 240°C for approximately 2 h after the analysis cycle was performed to wash out blonanserin residue in the GC column. Quantitation was performed by external standard analyses and the validation was carried out according to International Conference on Harmonization validation guidelines Q2A and Q2B. The method was shown to be specific (no interference in the blank solution), linear (correlation coefficients ≥0.99998, n = 10), accurate (average recoveries between 94.1 and 101.7%), precise (intra-day and inter-day precision ≤2.6%), sensitive (limit of detection ≤0.2 ng, and limit of quantitation ≤0.7 ng), robust (small variations of carrier gas flow, initial oven temperature, temperature ramping rate, injector and detector temperatures did not significantly affect the system suitability test parameters and peak areas) and stable (reference standard and sample solutions were stable over 48 h). This extensively validated method is ready to be used for the quality control of blonanserin.

  19. Validation of a GC-MS method for the estimation of dithiocarbamate fungicide residues and safety evaluation of mancozeb in fruits and vegetables.

    Science.gov (United States)

    Mujawar, Sumaiyya; Utture, Sagar C; Fonseca, Eddie; Matarrita, Jessie; Banerjee, Kaushik

    2014-05-01

    A sensitive and rugged residue analysis method was validated for the estimation of dithiocarbamate fungicides in a variety of fruit and vegetable matrices. The sample preparation method involved reaction of dithiocarbamates with Tin(II) chloride in aqueous HCl. The CS2 produced was absorbed into an isooctane layer and estimated by GC-MS selected ion monitoring. Limit of quantification (LOQ) was ⩽40μgkg(-1) for grape, green chilli, tomato, potato, brinjal, pineapple and chayote and the recoveries were within 75-104% (RSD<15% at LOQ). The method could be satisfactorily applied for analysis of real world samples. Dissipation of mancozeb, the most-used dithiocarbamate fungicide, in field followed first+first order kinetics with pre-harvest intervals of 2 and 4days in brinjal, 7 and 10days in grapes and 0day in chilli at single and double dose of agricultural applications. Cooking practices were effective for removal of mancozeb residues from vegetables. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. High-throughput method for the determination of residues of β-lactam antibiotics in bovine milk by LC-MS/MS.

    Science.gov (United States)

    Jank, Louise; Martins, Magda Targa; Arsand, Juliana Bazzan; Hoff, Rodrigo Barcellos; Barreto, Fabiano; Pizzolato, Tânia Mara

    2015-01-01

    This study describes the development and validation procedures for scope extension of a method for the determination of β-lactam antibiotic residues (ampicillin, amoxicillin, penicillin G, penicillin V, oxacillin, cloxacillin, dicloxacillin, nafcillin, ceftiofur, cefquinome, cefoperazone, cephapirine, cefalexin and cephalonium) in bovine milk. Sample preparation was performed by liquid-liquid extraction (LLE) followed by two clean-up steps, including low temperature purification (LTP) and a solid phase dispersion clean-up. Extracts were analysed using a liquid chromatography-electrospray-tandem mass spectrometry system (LC-ESI-MS/MS). Chromatographic separation was performed in a C18 column, using methanol and water (both with 0.1% of formic acid) as mobile phase. Method validation was performed according to the criteria of Commission Decision 2002/657/EC. Main validation parameters such as linearity, limit of detection, decision limit (CCα), detection capability (CCβ), accuracy, and repeatability were determined and were shown to be adequate. The method was applied to real samples (more than 250) and two milk samples had levels above maximum residues limits (MRLs) for cloxacillin - CLX and cefapirin - CFAP.

  1. Evaluation and validation of a multi-residue method based on biochip technology for the simultaneous screening of six families of antibiotics in muscle and aquaculture products.

    Science.gov (United States)

    Gaudin, Valérie; Hedou, Celine; Soumet, Christophe; Verdon, Eric

    2016-01-01

    The Evidence Investigator™ system (Randox, UK) is a biochip and semi-automated system. The microarray kit II (AM II) is capable of detecting several compounds belonging to different families of antibiotics: quinolones, ceftiofur, thiamphenicol, streptomycin, tylosin and tetracyclines. The performance of this innovative system was evaluated for the detection of antibiotic residues in new matrices, in muscle of different animal species and in aquaculture products. The method was validated according to the European Decision No. EC/2002/657 and the European guideline for the validation of screening methods, which represents a complete initial validation. The false-positive rate was equal to 0% in muscle and in aquaculture products. The detection capabilities CCβ for 12 validated antibiotics (enrofloxacin, difloxacin, ceftiofur, desfuroyl ceftiofur cysteine disulfide, thiamphenicol, florfenicol, tylosin, tilmicosin, streptomycin, dihydrostreptomycin, tetracycline, doxycycline) were all lower than the respective maximum residue limits (MRLs) in muscle from different animal origins (bovine, ovine, porcine, poultry). No cross-reactions were observed with other antibiotics, neither with the six detected families nor with other families of antibiotics. The AM II kit could be applied to aquaculture products but with higher detection capabilities from those in muscle. The detection capabilities CCβ in aquaculture products were respectively at 0.25, 0.10 and 0.5 of the respective MRL in aquaculture products for enrofloxacin, tylosin and oxytetracycline. The performance of the AM II kit has been compared with other screening methods and with the performance characteristics previously determined in honey.

  2. Numerical Evaluation of Temperature Field and Residual Stresses in an API 5L X80 Steel Welded Joint Using the Finite Element Method

    Directory of Open Access Journals (Sweden)

    Jailson A. Da Nóbrega

    2016-01-01

    Full Text Available Metallic materials undergo many metallurgical changes when subjected to welding thermal cycles, and these changes have a considerable influence on the thermo-mechanical properties of welded structures. One method for evaluating the welding thermal cycle variables, while still in the project phase, would be simulation using computational methods. This paper presents an evaluation of the temperature field and residual stresses in a multipass weld of API 5L X80 steel, which is extensively used in oil and gas industry, using the Finite Element Method (FEM. In the simulation, the following complex phenomena were considered: the variation in physical and mechanical properties of the material as a function of the temperature, welding speed and convection and radiation mechanisms. Additionally, in order to characterize a multipass weld using the Gas Tungsten Arc Welding process for the root pass and the Shielded Metal Arc Welding process for the filling passes, the analytical heat source proposed by Goldak and Chakravarti was used. In addition, we were able to analyze the influence of the mesh refinement in the simulation results. The findings indicated a significant variation of about 50% in the peak temperature values. Furthermore, changes were observed in terms of the level and profile of the welded joint residual stresses when more than one welding pass was considered.

  3. Comparison of an acetonitrile extraction/partitioning and “dispersive solid-phase extraction” method with classical multi-residue methods for the extraction of herbicide residues in barley samples

    NARCIS (Netherlands)

    Diez, C.; Traag, W.A.; Zommer, P.; Marinero, P.; Atienza, J.

    2006-01-01

    An acetonitrile/partitioning extraction and "dispersive solid-phase extraction (SPE)" method that provides high quality results with a minimum number of steps and a low solvent and glassware consumption was published in 2003. This method, suitable for the analysis of multiple classes of pesticide

  4. Quadratic residues and non-residues selected topics

    CERN Document Server

    Wright, Steve

    2016-01-01

    This book offers an account of the classical theory of quadratic residues and non-residues with the goal of using that theory as a lens through which to view the development of some of the fundamental methods employed in modern elementary, algebraic, and analytic number theory. The first three chapters present some basic facts and the history of quadratic residues and non-residues and discuss various proofs of the Law of Quadratic Reciprosity in depth, with an emphasis on the six proofs that Gauss published. The remaining seven chapters explore some interesting applications of the Law of Quadratic Reciprocity, prove some results concerning the distribution and arithmetic structure of quadratic residues and non-residues, provide a detailed proof of Dirichlet’s Class-Number Formula, and discuss the question of whether quadratic residues are randomly distributed. The text is a valuable resource for graduate and advanced undergraduate students as well as for mathematicians interested in number theory.

  5. [A Simultaneous Determination Method with Acetonitrile-n-Hexane Partitioning and Solid-Phase Extraction for Pesticide Residues in Livestock and Marine Products by GC-MS].

    Science.gov (United States)

    Yoshizaki, Mayuko; Kobayashi, Yukari; Shimizu, Masanori; Maruyama, Kouichi

    2015-01-01

    A simultaneous determination method was examined for 312 pesticides (including isomers) in muscle of livestock and marine products by GC-MS. The pesticide residues extracted from samples with acetone and n-hexane were purified by acetonitrile-n-hexane partitioning, and C18 and SAX/PSA solid-phase extraction without using GPC. Matrix components such as cholesterol were effectively removed. In recovery tests performed by this method using pork, beef, chicken and shrimp, 237-257 pesticides showed recoveries within the range of 70-120% in each sample. Validity was confirmed for 214 of the target pesticides by means of a validation test using pork. In comparison with the Japanese official method using GPC, the treatment time of samples and the quantity of solvent were reduced substantially.

  6. An optimized SPE-LC-MS/MS method for antibiotics residue analysis in ground, surface and treated water samples by response surface methodology- central composite design.

    Science.gov (United States)

    Mirzaei, Roya; Yunesian, Masoud; Nasseri, Simin; Gholami, Mitra; Jalilzadeh, Esfandiyar; Shoeibi, Shahram; Bidshahi, Hooshang Shafieyan; Mesdaghinia, Alireza

    2017-01-01

    Antibiotic residues are being constantly identified in environmental waters at low concentration. Growing concern has been expressed over the adverse environmental and human health effects even at low concentration. Hence, it is crucial to develop a multi-residues analytical method for antibiotics to generate a considerable dataset which are necessary in the assessment of aquatic toxicity of environmental waters for aquatic organisms and human health. This work aimed to develop a reliable and sensitive multi-residue method based on high performance liquid chromatography coupled with quadrupole-linear ion trap tandem mass spectrometry (HPLC-MS-MS). The method was optimized and validated for simultaneous determination of four classes of antibiotics including, β-lactam, macrolide, fluoroquinolone and nitro-imidazole in treated, ground and surface water matrices. In order to optimize the solid phase extraction process, main parameters influencing the extraction process including, pH, the volume of elution solvent and the amount of Na 4 EDTA were evaluated. The optimization of extraction process was carried out by response surface methodology using central composite design. Analysis of variance was performed for nine target antibiotics using response surface methodology. The extraction recoveries were found to be sensitive to the independent variables of pH, the volume of elution solvent and the amount of Na 4 EDTA. The extraction process was pH-dependent and pH was a significant model term in the extraction process of all target antibiotics. Method validation was performed in optimum operation conditions in which the recoveries were obtained in the range of 50-117% for seven antibiotics in spiked treated and ground water samples and for six antibiotics in spiked river water samples. Method validation parameters in terms of method detection limit were obtained in the range of 1-10 ng/L in treated water, 0.8-10 ng/L in the ground water and 0.8-25 ng/L in river water

  7. Weld Residual Stress in Corner Boxing Joints

    OpenAIRE

    Kazuyoshi, Matsuoka; Tokuharu, Yoshii; Ship Research Institute, Ministry of Transport; Ship Research Institute, Ministry of Transport

    1998-01-01

    Fatigue damage often occurs in corner boxing welded joints because of stress concentration and residual stress. The hot spot stress approach is applicable to stress concentration. However, the number of suitable methods for estimating residual stress in welded joints is limited. The purpose of this paper is to clarify the residual stress in corner boxing joints. The method of estimating residual stresses based on the inherent stress technique is presented. Residual stress measurements are per...

  8. Parallel Iterative Solution Methods for Linear Systems arising from Discretized PDE's

    OpenAIRE

    Vorst, H.A. van der

    1995-01-01

    In these notes we will present an overview of a number of related iterative methods for the solution of linear systems of equations. These methods are so-called Krylov projection type methods and the include popular methods as Conjugate Gradients, Bi-Conjugate Gradients, CGST Bi-CGSTAB, QMR, LSQR and GMRES. We will show how these methods can be derived from simple basic iteration formulas. We will not give convergence proofs, but we will refer for these, as far as available, to litterature. I...

  9. Residual basins

    International Nuclear Information System (INIS)

    D'Elboux, C.V.; Paiva, I.B.

    1980-01-01

    Exploration for uranium carried out over a major portion of the Rio Grande do Sul Shield has revealed a number of small residual basins developed along glacially eroded channels of pre-Permian age. Mineralization of uranium occurs in two distinct sedimentary units. The lower unit consists of rhythmites overlain by a sequence of black shales, siltstones and coal seams, while the upper one is dominated by sandstones of probable fluvial origin. (Author) [pt

  10. Evaluation of a new modified QuEChERS method for the monitoring of carbamate residues in high-fat cheeses by using UHPLC-MS/MS.

    Science.gov (United States)

    Hamed, Ahmed M; Moreno-González, David; Gámiz-Gracia, Laura; García-Campaña, Ana M

    2017-01-01

    A simple and efficient method for the determination of 28 carbamates in high-fat cheeses is proposed. The methodology is based on a modified quick, easy, cheap, effective, rugged, and safe procedure as sample treatment using a new sorbent (Z-Sep + ) followed by ultra-high performance liquid chromatography with tandem mass spectrometry determination. The method has been validated in different kinds of cheese (Gorgonzola, Roquefort, and Camembert), achieving recoveries of 70-115%, relative standard deviations lower than 13% and limits of quantification lower than 5.4 μg/kg, below the maximum residue levels tolerated for these compounds by the European legislation. The matrix effect was lower than ±30% for all the studied pesticides. The combination of ultra-high performance liquid chromatography and tandem mass spectrometry with this modified quick, easy, cheap, effective, rugged, and safe procedure using Z-Sep + allowed a high sample throughput and an efficient cleaning of extracts for the control of these residues in cheeses with a high fat content. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Investigation study for technological application of alternative methods for the energy exploitation of biomass/agricultural residues in Northern Greece

    Directory of Open Access Journals (Sweden)

    Zabaniotou Anastasia A.

    2007-01-01

    Full Text Available Biomass energy potential is addressed to be the most promising among the renewable energy sources, due to its spread and availability worldwide. Apart form that, biomass has the unique advantage among the rest of renewable energy sources, to be able to provide solid, liquid, and gaseous fuels that can be stored, transported, and utilized, far away from the point of origin. For the northern region of Macedonia in Greece, biomass utilization is considered to be a major issue, due to the considerably intensive regional agricultural activities. Wood by-products, fruit cores, rice husk and cotton gin waste provide a promising energy source for the region. The energy potential of the available agricultural biomass produced in the region is much enough to cover the 10% of the annual oil consumption utilized for thermal applications. However, the cost of energy utilization of biomass is considerably high due to the high cost of the logistics concerning the collection, transport, and storage of biomass. The available utilization technologies developed, to handle efficiently all different species of biomass, cover a wide technological range. One of the most promising technologies involving thermal treatment of biomass and the production of a gaseous fuel (biogas for industrial heat applications and electricity production, is the thermo chemical conversion. In the present work, an investigation concerning biomass potential for energy production in the region of central Macedonia in Greece, utilizing several locally produced biomass species, is conducted. Emphasis is put on the energy utilization of agricultural by-products and residues. Agricultural sector is of great importance due to the considerably intensive agricultural activities in the region of Central Macedonia. .

  12. Identification of improvised explosives residues using physical-chemical analytical methods under real conditions after an explosion

    Science.gov (United States)

    Kotrlý, Marek; Mareš, Bohumil; Turková, Ivana; Beroun, Ivo

    2016-05-01

    Within the analysis of cases relating to the use of explosives for crimes, we have experienced a shift from using industrial explosives towards substances made in amateur and illegal way. Availability of industrial explosives is increasingly limited to a narrow sphere of subjects with a relevant permission. Thus, on the part of perpetrators, terrorists, ever greater attention is paid to illegal production of explosives that are easily made from readily available raw materials. Another alarming fact is the availability of information found on the internet. Procedures of preparation are often very simple and do not require even a deeper professional knowledge. Explosive characteristics are not actually accessible for many of these substances (detonation velocity, sensitivity, working capacity, brisance, physical and chemical stability, etc.). Therefore, a project is being implemented, which on grounds of assessment of individual information available in literature and on the internet, aiming at choosing individual areas of potentially abusable substances (e.g. mixtures of nitric acid (98%) with organic substances, mixtures nitromethane and tetranitromethane with organic substances, mixtures of chlorates and perchlorates of alkali metals with organic substances, chemically individual compounds of organic base type of perchloric acid, azides, fulminates, acetylides, picrates, styphnates of heavy metals, etc.). It is directed towards preparation of these explosives also in non-stoichiometric mixtures, conducting test explosives, determination of explosive characteristics (if they are unknown) and analysis of both primary phases and post-blast residues through available analytical techniques, such as gas and liquid chromatography with mass detection, FTIR, micro-Raman spectrometry, electron microscopy with microanalysis and Raman microspectrometry directly in SEM chamber for analysis at the level of individual microparticles. The received characteristics will be used to

  13. A sensitive multi-residue method for the determination of 35 micropollutants including pharmaceuticals, iodinated contrast media and pesticides in water.

    Science.gov (United States)

    Valls-Cantenys, Carme; Scheurer, Marco; Iglesias, Mònica; Sacher, Frank; Brauch, Heinz-Jürgen; Salvadó, Victoria

    2016-09-01

    A sensitive, multi-residue method using solid-phase extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed to determine a representative group of 35 analytes, including corrosion inhibitors, pesticides and pharmaceuticals such as analgesic and anti-inflammatory drugs, five iodinated contrast media, β-blockers and some of their metabolites and transformation products in water samples. Few other methods are capable of determining such a broad range of contrast media together with other analytes. We studied the parameters affecting the extraction of the target analytes, including sorbent selection and extraction conditions, their chromatographic separation (mobile phase composition and column) and detection conditions using two ionisation sources: electrospray ionisation (ESI) and atmospheric pressure chemical ionisation (APCI). In order to correct matrix effects, a total of 20 surrogate/internal standards were used. ESI was found to have better sensitivity than APCI. Recoveries ranging from 79 to 134 % for tap water and 66 to 144 % for surface water were obtained. Intra-day precision, calculated as relative standard deviation, was below 34 % for tap water and below 21 % for surface water, groundwater and effluent wastewater. Method quantification limits (MQL) were in the low ng L(-1) range, except for the contrast agents iomeprol, amidotrizoic acid and iohexol (22, 25.5 and 17.9 ng L(-1), respectively). Finally, the method was applied to the analysis of 56 real water samples as part of the validation procedure. All of the compounds were detected in at least some of the water samples analysed. Graphical Abstract Multi-residue method for the determination of micropollutants including pharmaceuticals, iodinated contrast media and pesticides in waters by LC-MS/MS.

  14. Desarrollo de un método de CLAR-IR para la determinación de etanol residual en vacuna Development of a HPLC-IR method for determination of residual ethanol in vaccine

    Directory of Open Access Journals (Sweden)

    Matilde Cuevas Valdespino

    2009-08-01

    Full Text Available Los ingredientes farmacéuticos activos de la vacuna antimeningocócica cubana VA-MENGOC-BC TM (vesículas de membrana externa purificadas de Neisseria meningitidis, serogrupo B y polisacárido capsular purificado de Neisseria meningitidis, serogrupo C son conservados en etanol, de ahí que dicha vacuna posea un contenido de etanol residual, cuya concentración real no se conocía hasta el momento. Las regulaciones internacionales plantean que los productos biofarmacéuticos y sus ingredientes farmacéuticos activos deben tener bien caracterizadas todas sus impurezas, por lo que el objetivo de este trabajo fue el desarrollo de un método de determinación de etanol mediante cromatografía líquida de alta resolución-índice de refracción para estos fines y su comparación con un método utilizado frecuentemente para cuantificar este solvente, como es la cromatografía gaseosa. El método evaluado resultó ser útil y con una buena robustez para la determinación de este solvente orgánico en esta vacuna antimenigocócica. No se detectaron diferencias estadísticamente significativas entre los resultados obtenidos al evaluar las mismas muestras de vacuna mediante ambos métodos cromatográficos (cromatografía líquida de alta resolución y cromatografía gaseosa, lo que indica la posibilidad del uso de la cromatografía líquida de alta resolución en sustitución de la cromatografía gaseosa para esta determinación.Active pharmaceutical ingredients of Cuban anti-meningococcal vaccine VA-MENGOC-BC TM (vesicles of purified external membranes of Neisseria meningitidis, B serum-group, and purified capsular polysaccharide of Neisseria meningitidis, serum-group C are stored in ethanol, thus that such vaccine has residual ethanol content, of which real concentration is not known just now. International regulations propose that the biopharmaceutical products and its active pharmaceutical ingredients must to have well defined all impurities, thus

  15. Martingale residual-based method to control for confounders measured only in a validation sample in time-to-event analysis.

    Science.gov (United States)

    Burne, Rebecca M; Abrahamowicz, Michal

    2016-11-10

    Unmeasured confounding remains an important problem in observational studies, including pharmacoepidemiological studies of large administrative databases. Several recently developed methods utilize smaller validation samples, with information on additional confounders, to control for confounders unmeasured in the main, larger database. However, up-to-date applications of these methods to survival analyses seem to be limited to propensity score calibration, which relies on a strong surrogacy assumption. We propose a new method, specifically designed for time-to-event analyses, which uses martingale residuals, in addition to measured covariates, to enhance imputation of the unmeasured confounders in the main database. The method is applicable for analyses with both time-invariant data and time-varying exposure/confounders. In simulations, our method consistently eliminated bias because of unmeasured confounding, regardless of surrogacy violation and other relevant design parameters, and almost always yielded lower mean squared errors than other methods applicable for survival analyses, outperforming propensity score calibration in several scenarios. We apply the method to a real-life pharmacoepidemiological database study of the association between glucocorticoid therapy and risk of type II diabetes mellitus in patients with rheumatoid arthritis, with additional potential confounders available in an external validation sample. Compared with conventional analyses, which adjust only for confounders measured in the main database, our estimates suggest a considerably weaker association. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  16. Residual stress characterization in low transformation temperature 13%Cr-4%Ni stainless steel weld by neutron diffraction and the contour method

    International Nuclear Information System (INIS)

    Thibault, Denis; Bocher, Philippe; Thomas, Marc; Gharghouri, Michael; Cote, Marjolaine

    2010-01-01

    This study presents the results of residual stress characterization by neutron diffraction and the contour method on 13%Cr-4%Ni welds made using 410NiMo weld filler metal. The transverse, longitudinal and normal components of stress were determined by neutron diffraction. The longitudinal stress distribution was also measured by the contour method. The last bead of the weld was found to be in a state of triaxial compression while a part of the heat-affected zone as well as a region beneath the weld were in a state of longitudinal tension. These results are explained with reference to the low martensitic transformation start temperature (M s ) of the alloy. The same measurements were made on an identical weld that had undergone a standardized post-weld heat treatment. The maximum tensile stress was reduced from 534 to 136 MPa, and the maximum compressive stress was reduced from 371 to 152 MPa.

  17. An aptamer-based effective method for highly sensitive detection of chloramphenicol residues in animal-sourced food using real-time fluorescent quantitative PCR.

    Science.gov (United States)

    Duan, Ye; Wang, Lihui; Gao, Zhiqiang; Wang, Huishan; Zhang, Hexiao; Li, Hao

    2017-04-01

    Chloramphenicol (CAP) residues can not only harm human health through entering food chain, but also cause the spreading of drug-resistant bacteria, thereby leading to secondary environmental pollution. Therefore, it is in urgent need of establishing an efficient technology to detect CAP residues in animal-sourced food. In this study, a novel sensitive approach for detection of CAP was designed based on a CAP specific aptamer and real-time fluorescent quantitative PCR (qRT-PCR). The CAP specific aptamer was firstly hybridized with a biotin modified complementary probe, and then was immobilized on streptavidin conjugated magnetic beads through biotin. When CAP was added, the aptamer would specifically bind with CAP by forming a hairpin structure and be released from the magnetic beads for CAP detection by qRT-PCR. Factors (i.e., probe strand length, aptamer concentration, NaCl concentration and incubation time) that would influence the determination accuracy of this aptamer-based detection system were optimized. Under the optimized conditions, the present detection system exhibited a high sensitivity toward CAP with a limit of detection of 0.1ng/mL (linear range from 0.1 to 20ng/mL). Moreover, this detection system also showed high selectivity against thiamphenicol (TAP) and florfenicol (FF), which are CAP's structure analogs. Eventually, this detection system was applied for detecting CAP in real spiked milk. The recovery rate of CAP from spiked milk samples ranged from 94.0-102.0%. These results indicated this developed detection system a promising high sensitive and specific method of CAP residues detection in animal-sourced food. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Comparison of methods of zeta potential and residual turbidity of pectin solutions using calcium sulphate/aluminium sulphate as a precipitant

    Directory of Open Access Journals (Sweden)

    Kuljanin Tatjana A.

    2017-01-01

    Full Text Available The affinity of calcium ion binding from CaO used in the most common process of purification of sugar beet juice is relatively low. Therefore, large amounts of this compound are required. This paper presents the theoretical basis of a novel sugar beet juice purification method based on the application of the binary system CaSO4/Al2(SO4 . In order to monitor the process of coagulation and precipitation of pectin in the presence of CaSO4/Al2(SO43, two methods were compared: measurement of the zeta potential and of residual solution turbidity. The zeta potential of pectin solution was determined by electrophoretic method, while the residual turbidity was determined by spectrophotometry. Two model solutions of pectin (0.1 % w/w were investigated. Studies were performed with 10 different concentrations of the binary solution CaSO4/Al2(SO43 (50 - 500 g dm-3. The amount of the precipitant CaSO4/Al2(SO43 (1:1 w/w needed to achieve the minimum solution turbidity and charge neutralization of pectin particles (zero zeta potential were measured and compared. Colloidal destabilization occurred before a complete neutralization of the surface charge of pectin particles (zeta potential ~ 0 mV. Optimal quantities (490 - 705 mg g-1 pectin of the applied binary mixture, were obtained using both methods. This is much lower than the amount of CaO that is commonly used in the conventional process of sugar beet juice purification (about 9 g• g-1 pectin. The use of these precipitants could be important from both economic and environmental point of view. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR 31055

  19. A multilevel method for conductive-radiative heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Banoczi, J.M.; Kelley, C.T. [North Carolina State Univ., Raleigh, NC (United States)

    1996-12-31

    We present a fast multilevel algorithm for the solution of a system of nonlinear integro-differential equations that model steady-state combined radiative-conductive heat transfer. The equations can be formulated as a compact fixed point problem with a fixed point map that requires both a solution of the linear transport equation and the linear heat equation for its evaluation. We use fast transport solvers developed by the second author, to construct an efficient evaluation of the fixed point map and then apply the Atkinson-Brakhage, method, with Newton-GMRES as the coarse mesh solver, to the full nonlinear system.

  20. Application of Computer Algebra Systems to the Construction of the Collocations and Least Residuals Method for Solving the 3D Navier–Stokes Equations

    Directory of Open Access Journals (Sweden)

    V. P. Shapeev

    2014-01-01

    Full Text Available The method of collocations and least residuals (CLR, which was proposed previously for the numerical solution of two-dimensional Navier–Stokes equations governing the stationary flows of a viscous incompressible fluid, is extended here for the three-dimensional case. The solution is sought in the implemented version of the method in the form of an expansion in the basis solenoidal functions. At all stages of the CLR method construction, a computer algebra system (CAS is applied for the derivation and verification of the formulas of the method and for their translation into arithmetic operators of the Fortran language. For accelerating the convergence of iterations a sufficiently universal algorithm is proposed, which is simple in its implementation and is based on the use of the Krylov’s subspaces. The obtained computational formulas of the CLR method were verified on the exact analytic solution of a test problem. Comparisons with the published numerical results of solving the benchmark problem of the 3D driven cubic cavity flow show that the accuracy of the results obtained by the CLR method corresponds to the known high-accuracy solutions.

  1. Development and validation of multi-residue and multi-class method for antibacterial substances analysis in non-target feed by liquid chromatography - tandem mass spectrometry.

    Science.gov (United States)

    Patyra, Ewelina; Nebot, Carolina; Gavilán, Rosa Elvira; Cepeda, Alberto; Kwiatek, Krzysztof

    2018-03-01

    A confirmatory HPLC-MS/MS method for the determination of residues of 11 antibacterial substances from different therapeutic class (β-lactams, lincosamides, fluoroquinolones, macrolides, pleuromutilins and sulfonamides) in animal feeds has been developed. The sample preparation is based on extraction with 0.1% formic acid in acetonitrile. Separation of the analytes was performed on biphenyl column with a gradient of 0.1% formic acid in acetonitrile and 0.1% formic acid in Milli-Q water. The developed method was validated following the guidelines included in the European Union Commission Decision 2002/657/EC. Limits of detection ranging from 79.22 to 193.60 µg/kg; instrumental and analytical linearity coefficients were above 0.99 for matrix-match calibration; and relative recoveries ranging from 76.04% to 117.39%. Repeatability of the method was in the range of 2.41-19.76% (CV, %), whereas reproducibility ranged from 6.52 to 28.40% (CV %). The method shown to be efficient and precise for quantification of the 11 antibacterial substances in animal feed. The results demonstrate the feasibility of the method for routine use to monitor these substances in feed. The validated method was successfully applied to eight suspect feed samples collected from the Association of American Feed Control Officials (AFFCO) and feed manufactures from Galicia (Spain) in June and July 2017. Of these 8 non-target feeds, 5 were positive for the presence of tiamulin, tylosin and sulfadiazine.

  2. Validation of a liquid chromatography-mass spectrometry multi-residue method for the simultaneous determination of sulfonamides, tetracyclines, and pyrimethamine in milk.

    Science.gov (United States)

    Koesukwiwat, Urairat; Jayanta, Siripastr; Leepipatpiboon, Natchanun

    2007-01-26

    A multiresidue method suitable for confirmation and determination of six sulfonamides (SAs), three tetracyclines (TCs), and pyrimethamine (PYR) in cow milk was validated. Milk samples were extracted using copolymer Oasis HLB solid-phase extraction (SPE) and analyzed by liquid chromatography-electrospray mass spectrometry with positive ion mode. Estimated method detection limits (MDL) and method quantitation limits (MQL) ranged from 0.48 to 2.64 and 0.61 to 8.64ng/mL, respectively. These values are far lower than the maximum residue limits (MRLs) established by several control authorities. Excellent linear dynamic range was observed from the method quantitation limits to 300ng/mL with correlation coefficients better than 0.9900 for all compounds. The method was accurate with recoveries ranging from 72.01 to 97.39%. Good intra-precision and intermediate precision were obtained with RSD better than 11.08%. The method is fairly robust with sample pH being the only critical control point.

  3. Preparation of a Nanoemulsion with Carapa guianensis Aublet (Meliaceae Oil by a Low-Energy/Solvent-Free Method and Evaluation of Its Preliminary Residual Larvicidal Activity

    Directory of Open Access Journals (Sweden)

    Flávia L. M. Jesus

    2017-01-01

    Full Text Available Andiroba (Carapa guianensis seeds are the source of an oil with a wide range of biological activities and ethnopharmacological uses. However, few studies have devoted attention to innovative formulations, including nanoemulsions. The present study aimed to obtain a colloidal system with the andiroba oil using a low-energy and organic-solvent-free method. Moreover, the preliminary residual larvicidal activity of the nanoemulsion against Aedes aegypti was evaluated. Oleic and palmitic acids were the major fatty acids, in addition to the phytosterol β-sitosterol and limonoids (tetranortriterpenoids. The required hydrophile-lipophile was around 11.0 and the optimal nanoemulsion was obtained using polysorbate 85. The particle size distribution suggested the presence of small droplets (mean diameter around 150 nm and low polydispersity index (around 0.150. The effect of temperature on particle size distribution revealed that no major droplet size increase occurred. The preliminary residual larvicidal assay suggested that the mortality increased as a function of time. The present study allowed achievement of a potential bioactive oil in water nanoemulsion that may be a promising controlled release system. Moreover, the ecofriendly approach involved in the preparation associated with the great bioactive potential of C. guianensis makes this nanoemulsion very promising for valorization of this Amazon raw material.

  4. A synchrotron X-ray diffraction deconvolution method for the measurement of residual stress in thermal barrier coatings as a function of depth.

    Science.gov (United States)

    Li, C; Jacques, S D M; Chen, Y; Daisenberger, D; Xiao, P; Markocsan, N; Nylen, P; Cernik, R J

    2016-12-01

    The average residual stress distribution as a function of depth in an air plasma-sprayed yttria stabilized zirconia top coat used in thermal barrier coating (TBC) systems was measured using synchrotron radiation X-ray diffraction in reflection geometry on station I15 at Diamond Light Source, UK, employing a series of incidence angles. The stress values were calculated from data deconvoluted from diffraction patterns collected at increasing depths. The stress was found to be compressive through the thickness of the TBC and a fluctuation in the trend of the stress profile was indicated in some samples. Typically this fluctuation was observed to increase from the surface to the middle of the coating, decrease a little and then increase again towards the interface. The stress at the interface region was observed to be around 300 MPa, which agrees well with the reported values. The trend of the observed residual stress was found to be related to the crack distribution in the samples, in particular a large crack propagating from the middle of the coating. The method shows promise for the development of a nondestructive test for as-manufactured samples.

  5. Parameter validation of analytical methods of insecticide residue analyses in foods of animal origin, feed and water.

    Science.gov (United States)

    Debebe, Amsalu; Kuttalam, S

    2011-06-01

    The study was conducted to examine the interrelationship and coherence of analytical parameters in method validation. Recovery, sensitivity, linearity, precision and limits of detection (LOD) were tested in six methods for organochlorine and organophosphate insecticides. Compounds that fell out of the stipulated recovery, 70-120%, in a matrix have concurrently failed to meet the requirements for sensitivity (≥ 0.7), linearity (R² > 0.99) and precision (< 0.2) in the same matrix. Highest LOD was recorded in those compounds and matrices. Different from the conventional point estimate, a new approach was introduced for setting upper and lower confidence limits of the LOD in quantitative analyses.

  6. Assessment of wet explosion as a pretreatment method to enhance methane production from agricultural residues and energy crops

    DEFF Research Database (Denmark)

    Wang, Guangtao; Gavala, Hariklia N.; Skiadas, Ioannis

    2011-01-01

    In the present study, wet explosion has been studied as a pretreatment method for increasing the methane yield from wheat straw, miscantus and willow. Among the three biomasses tested, wheat straw and miscanthus were the most promising in terms of methane production, yielding around 265 m...... not necessarily imply increased methane yield....

  7. Multi-residue method for the determination of organochlorine pesticides in fish feed based on a cleanup approach followed by gas chromatography-triple quadrupole tandem mass spectrometry.

    Science.gov (United States)

    Nardelli, Valeria; dell'Oro, Daniela; Palermo, Carmen; Centonze, Diego

    2010-07-23

    A multi-residue method for the determination of organochlorine pesticides in fish feed samples was developed and optimized. The method is based on a cleanup step of the extracted fat, carried out by liquid-liquid extraction on diatomaceous earth cartridge with n-hexane/acetonitrile (80/20, v/v) followed by solid phase extraction (SPE) with silica gel-SCX cartridge, before the identification and quantification of the residues by gas chromatography-triple quadrupole tandem spectrometry (GC-MS/MS). Performance characteristics, such as accuracy, precision, linear range, limits of detection (LOD) and quantification (LOQ), for each pesticide were determined. Instrumental LODs ranged from 0.01 to 0.11 microg L(-1), LOQs were in the range of 0.02-0.35 microg L(-1), and calibration curves were linear (r2>0.999) in the whole range of explored concentrations (5-100 microg L(-1)). Repeatability values were in the range of 3-15%, evaluated from the relative standard deviation of six samples spiked at 100 microg kg(-1) of fat, and in compliance with that derived by the Horwitz's equation. No matrix effects or interfering substances were observed in fish feed analyses. The proposed method allowed high recoveries (92-116%) of spiked extracted fat samples at 100 microg kg(-1), and very low LODs (between 0.02 and 0.63 microg kg(-1)) and LOQs (between 0.05 and 2.09 microg kg(-1)) determined in fish feed samples. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  8. Multi-residue method for the detection of veterinary drugs in distillers grains by liquid chromatography-Orbitrap high resolution mass spectrometry.

    Science.gov (United States)

    Kaklamanos, George; Vincent, Ursula; von Holst, Christoph

    2013-12-27

    Distillers Grain (DG) is an important by-product of ethanol production. The ethanol production process uses only the starch portion of the plant and all the remaining nutrients, protein, fat, minerals, and vitamins remain in DGs, a valuable feed material for livestock. The use of antimicrobial drugs is helpful to limit harmful bacterial growth during the early part of the fermentation process. This can lead to the possible presence of contaminants in the by-products that are used in the food and feed industries, resulting in a major concern for the development of bacterial resistance in both humans and animals. To facilitate the detection of antimicrobial and other commonly used veterinary drugs in DGs, a liquid chromatography-high resolution mass spectrometry (LC-HRMS) method was developed targeting a wide range of 12 chemical classes of anti-bacterial substances and drugs, such as ionophore and non-ionophore authorized coccidiostats, banned coccidiostats, macrolides, tetracyclines, nitroimidazoles, amphenicols, quinolones, sulphonamides, tranquilizers, non-steroidal anti-inflammatory drugs and benzimidazoles. Following a simple and fast extraction step with a mixture of organic solvents, the extract was directly injected into the LC coupled to an Orbitrap mass analyzer. The identification of residues is based on accurate mass measurement. The high mass resolution of 50,000 full width at half maximum (FWHM) and corresponding narrow mass windows permitted a very selective and sensitive detection of the analytes in such a complex matrix. A single-laboratory validation procedure was carried out evaluating selectivity, sensitivity, linearity, precision and accuracy. The method showed satisfactory analytical performance for precision and trueness, and allowed the determination of the compounds at low concentration. The proposed multi-method demonstrated that liquid chromatography coupled to an Orbitrap mass spectrometer is a promising analytical technique, suitable for

  9. Automated multi-filtration cleanup with nitrogen-enriched activated carbon material as pesticide multi-residue analysis method in representative crop commodities.

    Science.gov (United States)

    Qin, Yuhong; Zhang, Jingru; Li, Yifan; Wang, Qiuxiao; Wu, Yangliu; Xu, Lanshu; Jin, Xiaojuan; Pan, Canping

    2017-09-15

    An automated multi-filtration cleanup (Auto m-FC) method with nitrogen-enriched activated carbon material based on modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) extracts was developed. It was applied to pesticide multi-residue analysis in six representative crop commodities. The automatic device was aimed to improve the cleanup efficiency and reduce manual operation workload in cleanup step. By controlling extracts volume, flow rate and Auto m-FC cycles, the device could finish cleanup process accurately. In this work, nitrogen-enriched activated carbon mixed with alternative sorbents and anhydrous magnesium sulfate (MgSO 4 ) was packed in a column for Auto m-FC and followed by liquid chromatography with tandem mass spectrometric (LC-MS/MS) detection. This newly developed carbon material showed excellent cleanup performance. It was validated by analyzing 23 pesticides in six representative matrices spiked at two concentration levels of 10 and 100μg/kg. Water addition volume, salts, sorbents, Auto m-FC procedure including the flow rate and the Auto m-FC cycles for each matrix were optimized. Then, three general Auto m-FC methods were introduced to high water content, high oil and starch content, difficult commodities. Spike recoveries were within 82 and 106% and 1-14% RSD for all analytes in the tested matrices. Matrix-matched calibrations were performed with the coefficients of determination over 0.997 between concentration levels of 10 and 1000μg/kg. The developed method was successfully applied to the determination of pesticide residues in market samples. Copyright © 2017. Published by Elsevier B.V.

  10. Improved parallel solution techniques for the integral transport matrix method

    International Nuclear Information System (INIS)

    Zerr, R. Joseph; Azmy, Yousry Y.

    2011-01-01

    Alternative solution strategies to the parallel block Jacobi (PBJ) method for the solution of the global problem with the integral transport matrix method operators have been designed and tested. The most straightforward improvement to the Jacobi iterative method is the Gauss-Seidel alternative. The parallel red-black Gauss-Seidel (PGS) algorithm can improve on the number of iterations and reduce work per iteration by applying an alternating red-black color-set to the subdomains and assigning multiple sub-domains per processor. A parallel GMRES(m) method was implemented as an alternative to stationary iterations. Computational results show that the PGS method can improve on the PBJ method execution time by up to 10´ when eight sub-domains per processor are used. However, compared to traditional source iterations with diffusion synthetic acceleration, it is still approximately an order of magnitude slower. The best-performing cases are optically thick because sub-domains decouple, yielding faster convergence. Further tests revealed that 64 sub-domains per processor was the best performing level of sub-domain division. An acceleration technique that improves the convergence rate would greatly improve the ITMM. The GMRES(m) method with a diagonal block pre conditioner consumes approximately the same time as the PBJ solver but could be improved by an as yet undeveloped, more efficient pre conditioner. (author)

  11. Development and comparison of two multi-residue methods for the analysis of select pesticides in honey bees, pollen, and wax by gas chromatography-quadrupole mass spectrometry.

    Science.gov (United States)

    Li, Yuanbo; Kelley, Rebecca A; Anderson, Troy D; Lydy, Michael J

    2015-08-01

    One of the hypotheses that may help explain the loss of honey bee colonies worldwide is the increasing potential for exposure of honey bees to complex mixtures of pesticides. To better understand this phenomenon, two multi-residue methods based on different extraction and cleanup procedures have been developed, and compared for the determination of 11 relevant pesticides in honey bees, pollen, and wax by gas chromatography-quadrupole mass spectrometry. Sample preparatory methods included solvent extraction followed by gel permeation chromatography (GPC) cleanup and cleanup using a dispersive solid-phase extraction with zirconium-based sorbents (Z-Sep). Matrix effects, method detection limits, recoveries, and reproducibility were evaluated and compared. Method detection limits (MDL) of the pesticides for the GPC method in honey bees, pollen, and wax ranged from 0.65 to 5.92 ng/g dw, 0.56 to 6.61 ng/g dw, and 0.40 to 8.30 ng/g dw, respectively, while MDLs for the Z-Sep method were from 0.33 to 4.47 ng/g dw, 0.42 to 5.37 ng/g dw, and 0.51 to 5.34 ng/g dw, respectively. The mean recoveries in all matrices and at three spiking concentrations ranged from 64.4% to 149.5% and 71.9% to 126.2% for the GPC and Z-Sep methods, with relative standard deviation between 1.5-25.3% and 1.3-15.9%, respectively. The results showed that the Z-Sep method was more suitable for the determination of the target pesticides, especially chlorothalonil, in bee hive samples. The Z-Sep method was then validated using a series of field-collected bee hive samples taken from honey bee colonies in Virginia. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. A validated RP-HPLC method for the determination of Irinotecan hydrochloride residues for cleaning validation in production area

    Directory of Open Access Journals (Sweden)

    Sunil Reddy

    2013-03-01

    Full Text Available Introduction: cleaning validation is an integral part of current good manufacturing practices in pharmaceutical industry. The main purpose of cleaning validation is to prove the effectiveness and consistency of cleaning in a given pharmaceutical production equipment to prevent cross contamination and adulteration of drug product with other active ingredient. Objective: a rapid, sensitive and specific reverse phase HPLC method was developed and validated for the quantitative determination of irinotecan hydrochloride in cleaning validation swab samples. Method: the method was validated using waters symmetry shield RP-18 (250mm x 4.6mm 5 µm column with isocratic mobile phase containing a mixture of 0.02 M potassium di-hydrogen ortho-phosphate, pH adjusted to 3.5 with ortho-phosphoric acid, methanol and acetonitrile (60:20:20 v/v/v. The flow rate of mobile phase was 1.0 mL/min with column temperature of 25°C and detection wavelength at 220nm. The sample injection volume was 100 µl. Results: the calibration curve was linear over a concentration range from 0.024 to 0.143 µg/mL with a correlation coefficient of 0.997. The intra-day and inter-day precision expressed as relative standard deviation were below 3.2%. The recoveries obtained from stainless steel, PCGI, epoxy, glass and decron cloth surfaces were more than 85% and there was no interference from the cotton swab. The detection limit (DL and quantitation limit (QL were 0.008 and 0.023 µg ml-1, respectively. Conclusion: the developed method was validated with respect to specificity, linearity, limit of detection and quantification, accuracy, precision and solution stability. The overall procedure can be used as part of a cleaning validation program in pharmaceutical manufacture of irinotecan hydrochloride.

  13. A simple method for the determination of residual amount of Hsub(2)Osub(2) a preservative present in the milk

    International Nuclear Information System (INIS)

    Srinivas, B.; Rao, V.R.S.; Kuriacose, J.C.

    1986-01-01

    A new method for the continuous determination of Hsub(2)Osub(2) is described based on the catalytic decomposition of Hsub(2)Osub(2) by LaCoOsub(3). The liberated oxygen is measured by a gas measuring burette. γ-irradiated catalyst enhances the catalytic activity and decreases the time required for complete decomposition. The procedure is suitable for microdetermination of Hsub(2)Osub(2) in various food products. (author)

  14. RNABindRPlus: a predictor that combines machine learning and sequence homology-based methods to improve the reliability of predicted RNA-binding residues in proteins.

    Science.gov (United States)

    Walia, Rasna R; Xue, Li C; Wilkins, Katherine; El-Manzalawy, Yasser; Dobbs, Drena; Honavar, Vasant

    2014-01-01

    Protein-RNA interactions are central to essential cellular processes such as protein synthesis and regulation of gene expression and play roles in human infectious and genetic diseases. Reliable identification of protein-RNA interfaces is critical for understanding the structural bases and functional implications of such interactions and for developing effective approaches to rational drug design. Sequence-based computational methods offer a viable, cost-effective way to identify putative RNA-binding residues in RNA-binding proteins. Here we report two novel approaches: (i) HomPRIP, a sequence homology-based method for predicting RNA-binding sites in proteins; (ii) RNABindRPlus, a new method that combines predictions from HomPRIP with those from an optimized Support Vector Machine (SVM) classifier trained on a benchmark dataset of 198 RNA-binding proteins. Although highly reliable, HomPRIP cannot make predictions for the unaligned parts of query proteins and its coverage is limited by the availability of close sequence homologs of the query protein with experimentally determined RNA-binding sites. RNABindRPlus overcomes these limitations. We compared the performance of HomPRIP and RNABindRPlus with that of several state-of-the-art predictors on two test sets, RB44 and RB111. On a subset of proteins for which homologs with experimentally determined interfaces could be reliably identified, HomPRIP outperformed all other methods achieving an MCC of 0.63 on RB44 and 0.83 on RB111. RNABindRPlus was able to predict RNA-binding residues of all proteins in both test sets, achieving an MCC of 0.55 and 0.37, respectively, and outperforming all other methods, including those that make use of structure-derived features of proteins. More importantly, RNABindRPlus outperforms all other methods for any choice of tradeoff between precision and recall. An important advantage of both HomPRIP and RNABindRPlus is that they rely on readily available sequence and sequence

  15. RNABindRPlus: A Predictor that Combines Machine Learning and Sequence Homology-Based Methods to Improve the Reliability of Predicted RNA-Binding Residues in Proteins

    Science.gov (United States)

    Walia, Rasna R.; Xue, Li C.; Wilkins, Katherine; El-Manzalawy, Yasser; Dobbs, Drena; Honavar, Vasant

    2014-01-01

    Protein-RNA interactions are central to essential cellular processes such as protein synthesis and regulation of gene expression and play roles in human infectious and genetic diseases. Reliable identification of protein-RNA interfaces is critical for understanding the structural bases and functional implications of such interactions and for developing effective approaches to rational drug design. Sequence-based computational methods offer a viable, cost-effective way to identify putative RNA-binding residues in RNA-binding proteins. Here we report two novel approaches: (i) HomPRIP, a sequence homology-based method for predicting RNA-binding sites in proteins; (ii) RNABindRPlus, a new method that combines predictions from HomPRIP with those from an optimized Support Vector Machine (SVM) classifier trained on a benchmark dataset of 198 RNA-binding proteins. Although highly reliable, HomPRIP cannot make predictions for the unaligned parts of query proteins and its coverage is limited by the availability of close sequence homologs of the query protein with experimentally determined RNA-binding sites. RNABindRPlus overcomes these limitations. We compared the performance of HomPRIP and RNABindRPlus with that of several state-of-the-art predictors on two test sets, RB44 and RB111. On a subset of proteins for which homologs with experimentally determined interfaces could be reliably identified, HomPRIP outperformed all other methods achieving an MCC of 0.63 on RB44 and 0.83 on RB111. RNABindRPlus was able to predict RNA-binding residues of all proteins in both test sets, achieving an MCC of 0.55 and 0.37, respectively, and outperforming all other methods, including those that make use of structure-derived features of proteins. More importantly, RNABindRPlus outperforms all other methods for any choice of tradeoff between precision and recall. An important advantage of both HomPRIP and RNABindRPlus is that they rely on readily available sequence and sequence

  16. A sensitive spectrofluorimetric method for the quantification of melamine residue in milk powder using the Mannich reaction in aqueous solutions.

    Science.gov (United States)

    Rima, Jamil; Assaker, Karine; El Omar, Fawaz; karim, Chawki bou

    2013-11-15

    The objective of this study was to develop a spectrofluorimetric method for the quantitative determination of melamine. The method was based on the complexation of melamine with a mixture of formaldehyde and chemicals including a ketone group, as described by the Mannich reaction. The complex was determined by spectrofluorimetric measurement as it is characterized by specific spectroscopic properties that are related to the chromophore of the ketone compounds. 1,3-Diphenylpropane-1,3-dione (DPPD) was tested as a ketone compound. The fluorescence spectrum of the complex presented a maximum of absorption at 325 nm.A quenching of the fluorescence occurred when melamine was added into the solution. The kinetic of fluorescence quenching was followed to determine quantitatively the melamine concentration. An internal standard was added to quantify melamine. The method was tested to determine the level of melamine in contaminated milk powder. The recovery value was 97% and the limit of detection was 0.007 μg mL(-1.) © 2013 Elsevier B.V. All rights reserved.

  17. Assessment of the Contour Method for 2-D Cross Sectional Residual Stress Measurements of Friction Stir Welded Parts of AA2024-T3—Numerical and Experimental Comparison

    DEFF Research Database (Denmark)

    Sonne, Mads Rostgaard; Carlone, Pierpaolo; Hattel, Jesper Henri

    2017-01-01

    The contour method is one of the newest techniques for obtaining residual stress fields from friction stir welded (FSW) parts, experimentally. This method has many advantages; however, edge effects coming from the process itself might introduce artifacts in the obtained results, and this was slig......The contour method is one of the newest techniques for obtaining residual stress fields from friction stir welded (FSW) parts, experimentally. This method has many advantages; however, edge effects coming from the process itself might introduce artifacts in the obtained results...

  18. A rapid SPE-based analytical method for UPLC/MS/MS determination of aminoglycoside antibiotic residues in bovine milk, muscle, and kidney.

    Science.gov (United States)

    Young, Michael S; van Tran, Kim; Goh, Evelyn; Shia, Jeremy C

    2014-01-01

    An SPE-based cleanup protocol was developed for ultra-performance LC (UPLC)/MS/MS determination of residues of the common aminoglycoside antibiotics streptomycin, dihydrostreptomycin, neomycin, and gentamicin in bovine milk, kidney, and muscle. Recoveries for all compounds except neomycin ranged from 80 to 104% for all matrixes studied; recoveries for neomycin ranged from 71 to 84%. Intraday and interday precision data were under 15% for all sample matrixes. Compared with other recently reported cleanup methods, less sample is required, the use of potentially dangerous reagents is minimized, and fewer manipulations are required by the analyst. A high throughput 96-well plate format was used for SPE cleanup and UPLC/MS analysis.

  19. RESIDUAL RISK ASSESSMENTS - RESIDUAL RISK ...

    Science.gov (United States)

    This source category previously subjected to a technology-based standard will be examined to determine if health or ecological risks are significant enough to warrant further regulation for Coke Ovens. These assesments utilize existing models and data bases to examine the multi-media and multi-pollutant impacts of air toxics emissions on human health and the environment. Details on the assessment process and methodologies can be found in EPA's Residual Risk Report to Congress issued in March of 1999 (see web site). To assess the health risks imposed by air toxics emissions from Coke Ovens to determine if control technology standards previously established are adequately protecting public health.

  20. Estimation of the uncertainty in a multiresidue method for the determination of pesticide residues in fruit and vegetables

    DEFF Research Database (Denmark)

    Christensen, Hanne Bjerre; Poulsen, Mette Erecius; Pedersen, Mikael

    2003-01-01

    . In the present study, recommendations from the International Organisation for Standardisation's (ISO) Guide to the Expression of Uncertainty and the EURACHEM/CITAC guide Quantifying Uncertainty in Analytical Measurements were followed to estimate the expanded uncertainties for 153 pesticides in fruit......The estimation of uncertainty of an analytical result has become important in analytical chemistry. It is especially difficult to determine uncertainties for multiresidue methods, e.g. for pesticides in fruit and vegetables, as the varieties of pesticide/commodity combinations are many...

  1. A Parallel Implicit Reconstructed Discontinuous Galerkin Method for Compressible Flows on Hybrid Grids

    Science.gov (United States)

    Xia, Yidong

    a computer program. By using an AD tool, the manpower can be significantly reduced for deriving the flux Jacobians, which can be quite complicated, tedious, and error-prone if done by hand or symbolic arithmetic software, depending on the complexity of the numerical flux scheme. In addition, the workload for code maintenance can also be largely reduced in case the underlying flux scheme is updated. The approximate system of linear equations arising from the Newton linearization is solved by the general minimum residual (GMRES) algorithm with lower-upper symmetric gauss-seidel (LUSGS) preconditioning. This GMRES+LU-SGS linear solver is the most robust and efficient for implicit time integration of the discretized Navier-Stokes equations when the AD-based flux Jacobians are provided other than the other two approaches. The developed HWENO(P1P2) method is used to compute a variety of well-documented compressible inviscid and viscous flow test cases on 3D hybrid grids, including some standard benchmark test cases such as the Sod shock tube, flow past a circular cylinder, and laminar flow past a at plate. The computed solutions are compared with either analytical solutions or experimental data, if available to assess the accuracy of the HWENO(P 1P2) method. Numerical results demonstrate that the HWENO(P 1P2) method is able to not only enhance the accuracy of the underlying HWENO(P1) method, but also ensure the linear and non-linear stability at the presence of strong discontinuities. An extensive study of grid convergence analysis on various types of elements: tetrahedron, prism, hexahedron, and hybrid prism/hexahedron, for a number of test cases indicates that the developed HWENO(P1P2) method is able to achieve the designed third-order accuracy of spatial convergence for smooth inviscid flows: one order higher than the underlying second-order DG(P1) method without significant increase in computing costs and storage requirements. The performance of the the developed

  2. Ultrahigh-performance liquid chromatography electrospray ionization Q-Orbitrap mass spectrometry for the analysis of 451 pesticide residues in fruits and vegetables: method development and validation.

    Science.gov (United States)

    Wang, Jian; Chow, Willis; Chang, James; Wong, Jon W

    2014-10-22

    This paper presents an application of ultrahigh-performance liquid chromatography electrospray ionization quadrupole Orbitrap high-resolution mass spectrometry (UHPLC/ESI Q-Orbitrap MS) for the determination of 451 pesticide residues in fruits and vegetables. Pesticides were extracted from samples using the QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure. UHPLC/ESI Q-Orbitrap MS in full MS scan mode acquired full MS data for quantification, and UHPLC/ESI Q-Orbitrap Full MS/dd-MS(2) (i.e., data-dependent scan mode) obtained product ion spectra for identification. UHPLC/ESI Q-Orbitrap MS quantification was achieved using matrix-matched standard calibration curves along with the use of isotopically labeled standards or a chemical analogue as internal standards to achieve optimal method accuracy. The method performance characteristics include overall recovery, intermediate precision, and measurement uncertainty evaluated according to a nested experimental design. For the 10 matrices studied, 94.5% of the pesticides in fruits and 90.7% in vegetables had recoveries between 81 and 110%; 99.3% of the pesticides in fruits and 99.1% of the pesticides in vegetables had an intermediate precision of ≤20%; and 97.8% of the pesticides in fruits and 96.4% of the pesticides in vegetables showed measurement uncertainty of ≤50%. Overall, the UHPLC/ESI Q-Orbitrap MS demonstrated acceptable performance for the quantification of pesticide residues in fruits and vegetables. The UHPLC/ESI Q-Orbitrap Full MS/dd-MS(2) along with library matching showed great potential for identification and is being investigated further for routine practice.

  3. Methods for storage and disposal of residues from wastewater treatment of former uranium mining and milling facilities in Germany

    International Nuclear Information System (INIS)

    Larue, J.; Weiss, D.; Kiessig, G.

    2002-01-01

    In connection with the flooding of uranium mines in Saxony and Thuringia, there are contaminated pit waters that must be purified before discharge into surface waters. The expected duration of the water purification process until concentrations of natural radionuclides, various heavy metals and arsenic are low enough to allow direct discharge into surface waters amounts to decades . To prevent or minimize the leaching of the contaminants from the sludge of the water treatment in the long term, the contaminants are either transformed into chemical compounds of low solubility or affixed within ion exchange resins. Due to the accumulation of those contaminants during the water processing procedure, the residua must be disposed of for reasons of radiation protection and waste management. A final storage of the residua in accord with nuclear regulatory stipulations is unnecessary because of the contamination levels and also because of the mining origin. The method of residua-storage chosen to be best suited to a particular site has to be based on costs-to-benefit analyses, giving due consideration to the different aspects e.g. radiation and environmental protection, long term safety, form of immobilization, site specific conditions. These methods will be described and illustrated using specific examples of applications. (author)

  4. Development and validation of a multiclass method for the determination of antibiotic residues in honey using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    El Hawari, Khaled; Mokh, Samia; Doumyati, Samah; Al Iskandarani, Mohamad; Verdon, Eric

    2017-04-01

    A new, simple and fast method was developed for the determination of multi-class antibiotic residues in honey (sulfonamides, tetracyclines, macrolides, lincosamides and aminoglycosides). Separation and determination were carried out by LC-MS/MS. During sample preparation, various parameters affecting extraction efficiency were examined, including the type of solvent, pH, efficiencies of cleavage of N-glycosidic linkages by hydrochloric acid, ultrasonic extraction and its duration compared with shaking, along with dispersive SPE clean-up. Experiments with fortified samples demonstrated that 10 min of ultrasonic treatment with acidified methanol (HCl 2 M) followed by dispersive SPE clean-up with 50 mg PSA gave an effective sample preparation method for several classes of antibiotics in honey. Anhydroerythromycin A, erythromycin A enol ether and desmycosin were used as markers for the presence of erythromycin A and tylosin A in honey samples. The method was validated according to European Commission Decision (EC) No. 2002/657. The recoveries of analytes ranged from 85% to 111%. Repeatability and intra-laboratory reproducibility were honey test material 02270 through a FAPAS proficiency test (PT) for the determination of tetracyclines. PT results were obtained within a z-score range of ±2, proving that the validated method is suitable for routine analysis to ensure the quality of honey.

  5. Incorporação de CuSO4 residual em argamassa, como método de disposição final Incorporation of residual cuso4 into cement as a final disposal method

    Directory of Open Access Journals (Sweden)

    Matheus Paes Paschoalino

    2006-07-01

    Full Text Available Residual CuSO4 was incorporated into the mass utilized for cement preparation. To a cement mass with 1:0.5:5 of cement, lime and sand to 0.25, 0.50, 0.75 and 1.00% of residual CuSO4 were added. The sulfate was mixed separately with lime and water to induce metal precipitation. The hardened test bodies were submerged in Milli-Q water for three months. No Cu was detected in the water by Atomic Absorption Spectrometry. The best proportion for mechanical resistance and porosity is 0.50%. The cement is adequate for non-structural objects.

  6. A simple method for detection of gunshot residue particles from hands, hair, face, and clothing using scanning electron microscopy/wavelength dispersive X-ray (SEM/WDX).

    Science.gov (United States)

    Kage, S; Kudo, K; Kaizoji, A; Ryumoto, J; Ikeda, H; Ikeda, N

    2001-07-01

    We devised a simple and rapid method for detection of gunshot residue (GSR) particles, using scanning electron microscopy/wavelength dispersive X-ray (SEM/WDX) analysis. Experiments were done on samples containing GSR particles obtained from hands, hair, face, and clothing, using double-sided adhesive coated aluminum stubs (tape-lift method). SEM/WDX analyses for GSR were carried out in three steps: the first step was map analysis for barium (Ba) to search for GSR particles from lead styphnate primed ammunition, or tin (Sn) to search for GSR particles from mercury fulminate primed ammunition. The second step was determination of the location of GSR particles by X-ray imaging of Ba or Sn at a magnification of x 1000-2000 in the SEM, using data of map analysis, and the third step was identification of GSR particles, using WDX spectrometers. Analysis of samples from each primer of a stub took about 3 h. Practical applications were shown for utility of this method.

  7. Determination of Anthracycline Drug Residual in Cleaning Validation Swabs of Stainless-Steel Equipment after Production of Cytostatic Injections Using HPLC Analytical Method

    Directory of Open Access Journals (Sweden)

    Zuzana Slivová

    2015-01-01

    Full Text Available Standard cleaning procedures of production line equipment were verified after manufacture of cytostatic injections containing Anthracycline derivate substance. Residual content of Anthracycline drug substance on stainless-steel equipment surface was determined using swab sampling with a specific HPLC-DAD analysis. The acceptance limit was decided as 200.0 μg/100 cm2. Recovery from the stainless-steel surface was 90.1%. Linearity of the method was observed in the concentration range of 0.155–194 μg/mL when estimated using Zorbax TMS (5 μm, 0.25 m × 4.6 mm ID column at 1.3 mL/min flow rate and 254 nm (DAD 190–600 nm. The mobile phase consisted of lauryl hydrogen sulphate solution (3.7 g/L : methanol : acetonitrile (54 : 16 : 30, v/v/v with pH adjusted to 2.5 using phosphoric acid (85%. The LOD and LOQ for Anthracycline derivate were found to be 0.047 and 0.155 μg/mL, respectively. The method validation confirmed the method provides acceptable degree of selectivity, linearity, accuracy, and precision for the intended purposes.

  8. β-lactam antibiotics residues analysis in bovine milk by LC-ESI-MS/MS: a simple and fast liquid-liquid extraction method.

    Science.gov (United States)

    Jank, L; Hoff, R B; Tarouco, P C; Barreto, F; Pizzolato, T M

    2012-01-01

    This study presents the development and validation of a simple method for the detection and quantification of six β-lactam antibiotics residues (ceftiofur, penicillin G, penicillin V, oxacillin, cloxacillin and dicloxacillin) in bovine milk using a fast liquid-liquid extraction (LLE) for sample preparation, followed by liquid chromatography-electrospray-tandem mass spectrometry (LC-MS/MS). LLE consisted of the addition of acetonitrile to the sample, followed by addition of sodium chloride, centrifugation and direct injection of an aliquot into the LC-MS/MS system. Separation was performed in a C(18) column, using acetonitrile and water, both with 0.1% of formic acid, as mobile phase. Method validation was performed according to the criteria of Commission Decision 2002/657/EC. Limits of detection ranged from 0.4 (penicillin G and penicillin V) to 10.0 ng ml(-1) (ceftiofur), and linearity was achieved. The decision limit (CCα), detection capability (CCβ), accuracy, inter- and intra-day repeatability of the method are reported.

  9. Determination of fenobucarb residues in animal and aquatic food products using liquid chromatography-tandem mass spectrometry coupled with a QuEChERS extraction method.

    Science.gov (United States)

    Zheng, Weijia; Park, Jin-A; Zhang, Dan; Abd El-Aty, A M; Kim, Seong-Kwan; Cho, Sang-Hyun; Choi, Jeong-Min; Shim, Jae-Han; Chang, Byung-Joon; Kim, Jin-Suk; Shin, Ho-Chul

    2017-07-15

    A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction method coupled with liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI + /MS-MS) was developed for quantification of fenobucarb residues in animal food products, such as porcine muscle, egg, and whole milk, and aquatic food products, such as eel, flatfish, and shrimp. Acetonitrile with the addition of 0.1% trifluoroacetic acid was employed as an extraction solvent and was compared with acetonitrile alone and 0.1% formic acid in acetonitrile. All extracted samples were purified using C18 sorbent. The best extraction efficiencies, expressed as recovery at two spiking levels equivalent to 1- and 2-times the limit of quantification (LOQ=2μg/kg) were achieved using 0.1% trifluoroacetic acid in acetonitrile and ranged from 61.38 to 102.21% in all matrices, with relative standard deviations (RSDs) 20%). Six-point matrix-matched calibration was used for quantification and the determination coefficients were good (R 2 ≥0.9865). The method was verified by application to samples purchased from local markets and none of the samples tested positive. In conclusion, the developed method is simple and versatile and can be used for the routine detection of fenobucarb in different animal food products having varying protein and fat contents with satisfactory accuracy and precision. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Optimization of a multi-residue method for 101 pesticides in green tea leaves using gas chromatography–tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Xue Hou

    Full Text Available ABSTRACT A method for analysis of 101 pesticide residues in tea leaves was developed and validated for the first time. Pure acetonitrile was used as extraction solvent rather than acetonitrile after matrix hydration based on the amount of co-extracts and recoveries performance. During clean-up procedure, primary-secondary amine/graphitized carbon black (500 mg was selected, which exhibited outstanding properties in clean-up capabilities and recoveries of pesticides comparing to primary-secondary amine/graphitized carbon black (250 mg, NH2-Carbon and TPT absorbents. The method was validated employing gas chromatography coupled to tandem mass spectrometry at the spiked concentration levels of 0.050 and 0.100 mg kg−1. For most of the targeted pesticides, the percent recoveries range from 70 to 120%, with relative standard deviations <20%. The linear correlation coefficients (r 2 were higher than 0.99 at concentration levels of 0.025–0.250 mg kg−1. Limits of quantification ranged from 1.1 to 25.3 µg kg−1 for all pesticides. The developed method was successfully applied to the determination of pesticides in tea leaf samples.

  11. Sensitive determination of mixtures of neonicotinoid and fungicide residues in pollen and single bumblebees using a scaled down QuEChERS method for exposure assessment.

    Science.gov (United States)

    David, Arthur; Botías, Cristina; Abdul-Sada, Alaa; Goulson, Dave; Hill, Elizabeth M

    2015-10-01

    To accurately estimate exposure of bees to pesticides, analytical methods are needed to enable quantification of nanogram/gram (ng/g) levels of contaminants in small samples of pollen or the individual insects. A modified QuEChERS extraction method coupled with ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) analysis was tested to quantify residues of 19 commonly used neonicotinoids and fungicides and the synergist, piperonyl butoxide, in 100 mg samples of pollen and in samples of individual bumblebees (Bombus terrestris). Final recoveries ranged from 71 to 102 % for most compounds with a repeatability of below 20 % for both pollen and bumblebee extracts spiked at 5 and 40 ng/g. The method enables the detection of all compounds at sub-ng/g levels in both matrices and the method detection limits (MDL) ranged from 0.01 to 0.84 ng/g in pollen and 0.01 to 0.96 ng/g in individual bumblebees. Using this method, mixtures of neonicotinoids (thiamethoxam, clothianidin, imidacloprid and thiacloprid) and fungicides (carbendazim, spiroxamine, boscalid, tebuconazole, prochloraz, metconazole, fluoxastrobin, pyraclostrobin and trifloxystrobin) were detected in pollens of field bean, strawberry and raspberry at concentrations ranging from neonicotinoids and from MDL, and in some bees, the fungicides carbendazim, boscalid, tebuconazole, flusilazole and metconazole were present at concentrations between 0.80 to 30 ng/g. This new method allows the analysis of mixtures of neonicotinoids and fungicides at trace levels in small quantities of pollen and individual bumblebees and thus will facilitate exposure assessment studies.

  12. Residual stress measurements of welded stainless steel 304 plate using the HANARO residual stress instrument

    International Nuclear Information System (INIS)

    Mun, M. K.; Lee, C. H.; Em, V. T.

    2001-01-01

    In order to nondestructively measure in-depth residual stress distribution of the metallic materials, it is unique method to use neutron diffraction. In this paper the principles of residual stress measurements by neutron diffraction is described. The residual stress distribution of welded strainless steeel 304 plate using te HANARO residual stress instrument is also described

  13. Highly sensitive in vitro methods for detection of residual undifferentiated cells in retinal pigment epithelial cells derived from human iPS cells.

    Directory of Open Access Journals (Sweden)

    Takuya Kuroda

    Full Text Available Human induced pluripotent stem cells (hiPSCs possess the capabilities of self-renewal and differentiation into multiple cell types, and they are free of the ethical problems associated with human embryonic stem cells (hESCs. These characteristics make hiPSCs a promising choice for future regenerative medicine research. There are significant obstacles, however, preventing the clinical use of hiPSCs. One of the most obvious safety issues is the presence of residual undifferentiated cells that have tumorigenic potential. To locate residual undifferentiated cells, in vivo teratoma formation assays have been performed with immunodeficient animals, which is both costly and time-consuming. Here, we examined three in vitro assay methods to detect undifferentiated cells (designated an in vitro tumorigenicity assay: soft agar colony formation assay, flow cytometry assay and quantitative real-time polymerase chain reaction assay (qRT-PCR. Although the soft agar colony formation assay was unable to detect hiPSCs even in the presence of a ROCK inhibitor that permits survival of dissociated hiPSCs/hESCs, the flow cytometry assay using anti-TRA-1-60 antibody detected 0.1% undifferentiated hiPSCs that were spiked in primary retinal pigment epithelial (RPE cells. Moreover, qRT-PCR with a specific probe and primers was found to detect a trace amount of Lin28 mRNA, which is equivalent to that present in a mixture of a single hiPSC and 5.0×10⁴ RPE cells. Our findings provide highly sensitive and quantitative in vitro assays essential for facilitating safety profiling of hiPSC-derived products for future regenerative medicine research.

  14. Multi-residue method for trace level determination of pharmaceuticals in environmental samples using liquid chromatography coupled to triple quadrupole mass spectrometry.

    Science.gov (United States)

    Grabic, Roman; Fick, Jerker; Lindberg, Richard H; Fedorova, Ganna; Tysklind, Mats

    2012-10-15

    A multi-residue method for the simultaneous determination of more than 90 pharmaceuticals in water samples was developed and validated. The developed method utilizes a single liquid chromatography-tandem mass spectrometry (LC-MS/MS) run after sample enrichment using solid-phase extraction (SPE). The pharmaceuticals included in this method were chosen based on their potency (effect/concentration ratio) and potential to bioaccumulate in fish. Because the selection was based on ecotoxicological criteria and not on ease of detection, the pharmaceuticals have a wide range of physico-chemical properties and represent 27 distinct classes. No method for surface, waste water or similar matrices was previously described for 52 of the 100 target analytes. Four chromatographic columns were tested to optimize the separation prior to detection by mass spectrometry (MS). The resulting method utilizes a Hypersil Gold aQ column. Three different water matrices were tested during method validation: Milli-Q water, surface water (river water from the Umea River) and effluent from the Umea waste water treatment plant (WWTP). Four of the selected pharmaceuticals exhibited poor method efficiency in all matrices. Amiodarone, Dihydroergotamine, Perphenazine and Terbutalin were omitted from the final analytical method. In addition, five compounds were excluded from the method for surface water (Atorvastatin, Chloropromazin, Dipyridamol, Furosemid and Ranitidin) and three other pharmaceuticals (Glibenclamid, Glimepirid and Meclozine) from waste water method respectively. Absolute recoveries were above 70% for Milli-Q water, surface water, and sewage effluent for most pharmaceuticals. The limits of quantification (LOQs) ranged from 0.05 to 50 ng L(-1) (median 5 ng L(-1)). The use of matrix-matched standards led to the elimination of ionization enhancement or suppression. The recoveries of the method for real matrices were in the range of 23-134% for surface water (only three compounds were

  15. Statistical inference on residual life

    CERN Document Server

    Jeong, Jong-Hyeon

    2014-01-01

    This is a monograph on the concept of residual life, which is an alternative summary measure of time-to-event data, or survival data. The mean residual life has been used for many years under the name of life expectancy, so it is a natural concept for summarizing survival or reliability data. It is also more interpretable than the popular hazard function, especially for communications between patients and physicians regarding the efficacy of a new drug in the medical field. This book reviews existing statistical methods to infer the residual life distribution. The review and comparison includes existing inference methods for mean and median, or quantile, residual life analysis through medical data examples. The concept of the residual life is also extended to competing risks analysis. The targeted audience includes biostatisticians, graduate students, and PhD (bio)statisticians. Knowledge in survival analysis at an introductory graduate level is advisable prior to reading this book.

  16. Loss of residual monomer from resilient lining materials processed by different methods = Perda de monômero residual de reembasadores resilientes processados por diferentes métodos

    Directory of Open Access Journals (Sweden)

    León, Blanca Liliana Torres

    2008-01-01

    Full Text Available Objetivo: Avaliar o monômero residual liberado de materiais resilientes para reembasamento polimerizados por diferentes métodos. Metodologia: Dois materiais foram testados: Ever-Soft polymerizado por banho quente de água ou por energia de microondas, e Light Liner polimerizado quimicamente e por luz visível (polimerização dual. O monômero residual liberado foi mensurado em 12 espécimes (40x10x0,3mm fabricados com cada material e método de polimerização. Os espécimes foram armazenados em água destilada por 168 horas a 37ºC, e analisados diariamente por espectrometria ultravioleta (Light Liner: 204nm, Ever-Soft: 206nm. Os dados foram analisados por ANOVA de fator único e teste de Bonferroni (a=0,05. O monômero residual liberado em relação ao tempo foi determinado por análise de regressão polinomial. Resultados: O monômero residual liberado em 168 horas do teste (µg/cm2 em espécimes polimerizados por banho de água quente (0,27±0,01µg/cm2 foi significativamente maior (P < 0,05 que em espécimes processados por energia de microondas (0,25±0,02µg/cm2. Ever-Soft mostrou uma redução na liberação de monomer residual com o tempo, tendendo a se estabilizar em 96 horas. Light Liner continuou a liberar monômero com o tempo. Conclusão: Ever-Soft pode ser polimerizado por energia de microondas. Os valores de monômero residual liberado foram baixos, e os níveis de monômero diminuíram com o tempo

  17. Analysis by the Residual Method for Estimate Market Value of Land on the Areas with Mining Exploitation in Subsoil under Future New Building

    Science.gov (United States)

    Gwozdz-Lason, Monika

    2017-12-01

    This paper attempts to answer some of the following questions: what is the main selling advantage of a plot of land on the areas with mining exploitation? which attributes influence on market value the most? and how calculate the mining influence in subsoil under future new building as market value of plot with commercial use? This focus is not accidental, as the paper sets out to prove that the subsoil load bearing capacity, as directly inferred from the local geotechnical properties with mining exploitation, considerably influences the market value of this type of real estate. Presented in this elaborate analysis and calculations, are part of the ongoing development works which aimed at suggesting a new technology and procedures for estimating the value of the land belonging to the third category geotechnical. Analysed the question was examined both in terms of the theoretical and empirical. On the basis of the analysed code calculations in residual method, numerical, statistical and econometric defined results and final conclusions. A market analysis yielded a group of subsoil stabilization costs which depend on the mining operations interaction, subsoil parameters, type of the contemplated structure, its foundations, selected stabilization method, its overall area and shape.

  18. Determination of chlorpropham (CIPC) residues, in the concrete flooring of potato stores, using quantitative (HPLC UV/VIS) and qualitative (GCMS) methods.

    Science.gov (United States)

    Douglas, Leisa; MacKinnon, Gillian; Cook, Gordon; Duncan, Harry; Briddon, Adrian; Seamark, Steven

    2018-03-01

    Isopropyl-N-(3-chlorophenyl) carbamate (CIPC, common name Chlorpropham) is commonly used for post-harvest sprout inhibition in stored potatoes. It is applied as a thermal fog which results in loss to the fabric of the store and the atmosphere. Recently, there have been concerns in the United Kingdom because of cross contamination of other crop commodities that were stored in buildings with a history of CIPC usage. This cross contamination may have occurred because of retained residues in the fabric of the stores. The retention of CIPC in concrete is poorly understood; therefore the requirement for a robust analytical method for the detection and quantification of CIPC in concrete is a critical first step in tackling this problem. A method using High-Performance Liquid Chromatography with ultraviolet detection (HPLC UV/VIS) was validated. CIPC recoveries at three concentration levels (0.4, 4.0 and 40.0 μg g -1 ) were in the range of 90.7-97.0% with relative standard deviations between 2.14 and 3.01%. The limits of detection and quantification were 0.03 and 0.1 μg g -1 , respectively. This study confirmed that CIPC was persistent in concrete to a depth of 4 cm, with >90% within the top 1 cm of the flooring. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Residue behaviors and dietary risk assessment of dinotefuran and its metabolites in Oryza sativa by a new HPLC-MS/MS method.

    Science.gov (United States)

    Li, Ruijuan; Liu, Tongjin; Cui, Shuhua; Zhang, Sicong; Yu, Jianlei; Song, Guochun

    2017-11-15

    In this study, we developed a new method to detect dinotefuran and its metabolites (UF and DN) in Oryza sativa (Rice) by HPLC-MS/MS in multiple reaction monitoring (MRM) modes. The recovery rates for dinotefuran, UF and DN were 82.3-85.8%, 83.7-89.0%, and 81.6-90.2%, respectively. The dissipation kinetics of dinotefuran in rice followed a combined first+first kinetic model, where the half-lives of dinotefuran and its metabolites were determined to be between 0.5 and 2.3days. The dinotefuran residue in brown rice sampled at day 7, 14, and 21 after the last application was 0.4131mg/kg with a very low risk quotient (RQ) value. We recommend that the safety interval of application for rice is 7days. The method developed in this study is simple and rapid, with high accuracy and precision which meet the requirements for quantitative analysis of dinotefuran in rice. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. A multi-residue method for determination of 70 organic micropollutants in surface waters by solid-phase extraction followed by gas chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Terzopoulou, Evangelia; Voutsa, Dimitra; Kaklamanos, George

    2015-01-01

    A multi-residue method, based on gas chromatography coupled to tandem mass spectrometry (GC-MS/MS), has been developed for the determination of 70 organic micropollutants from various chemical classes (organochlorinated, organophosphorous, triazines, carbamate and urea, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, pharmaceuticals, phenols, etc.) in surface waters. A single-step SPE extraction using OASIS HLB cartridges was employed for the recovery of target micropollutants. The method has been validated according to monitoring performance criteria of the Water Framework Directive, taking into account the approved guidelines on quality assurance and quality control. The recoveries ranged from 60 to 110 %, the coefficient of variation from 0.84 to 27.4 %, and the uncertainty from 6 to 37 %. The LOD varied from 6.0 to 40 ng/L. The limits of quantification for the priority pollutants anthracene, alachlor, atrazine, benzo(a)pyrene, chlorfenvinphos, diuron, isoproturon, nonylphenol, simazine, and terbutryn fulfill the criterion of diuron, isoproturon, salicylic acid, chlorfenvinphos, 1,2-benzanthracene, pyrene, diflubenzuron, and carbaryl exhibited the highest detection frequencies.

  1. Pasture residue amount and sowing method effects on establishment of overseeded cool-season grasses and on total annual production of herbage

    Science.gov (United States)

    Warm-season pasture residue may create problems for no-till overseeding with cool-season grasses in the USA Southern Plains. Removal of residue to facilitate overseeding, however, represents additional cost and requires labor that may not be available on small livestock enterprises. Field experiment...

  2. Disruptive tension under normalized atmospheric pulse and residual tension on lightning arresters power systems: statistical methods application. Practical results and comments; Ensaios de tensao disruptiva sob impulso atmosferico normalizado e tensao residual em para-raios para sistemas de potencia: a aplicacao de metodos estatisticos. Comentarios e resultados praticos

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, M.L.B. [ELETRONORTE, Brasilia (Brazil); Oliveira, A.L. [Eletricidade da Sao Paulo S.A. (ELETROPAULO), Sao Paulo, SP (Brazil)

    1991-12-31

    The necessity of complementary assays of disruptive tension under normalized atmospheric pulses and residual tension on lightning arresters, as well as the adequate use of a statistical treatment of its results are commented. Some statistical methods and its applicability on lightning arresters characteristics surveys, and its quality control are proposed 8 refs., 5 figs., 3 tabs.

  3. Methods for counting residual leukocytes in leukocyte-depleted plasma-a comparison between a routine hematology instrument, the Nageotte chamber, flow cytometry, and a fluorescent microscopy analyzer.

    Science.gov (United States)

    Petersson, Annika; Ekblom, Kim

    2017-05-01

    Counting very low levels of leukocytes is technically challenging but mandatory for quality control of leukocyte-depleted plasma. Established assays, such as flow cytometry and counting in the Nageotte chamber, are laborious and expensive. The aim of this study was to test two alternative assays, the cerebrospinal fluid program in the routine hematology analyzer ADVIA 2120 and a fluorescence microscopy analyzer, the ADAM-rWBC. Linearity, accuracy, and precision were established for the ADVIA 2120, the ADAM-rWBC analyzer and the Nageotte chamber with flow cytometry as the reference method. Two hundred consecutive leukocyte-depleted donor plasma samples were also tested. The ADAM-rWBC analyzer and the Nageotte chamber fulfilled all quality requirements. Flow cytometry fulfilled the requirements for linearity and precision. The ADVIA 2120 analyzer did not fully reach the quality criteria, and flow cytometry did not reach quality criteria on accuracy. No false-positive results on donor plasma samples were recorded. The ADAM-rWBC is suitable for the purpose of quality control of residual leukocytes in leukocyte-depleted plasma. For the ADVIA 2120, further improvements and studies are needed to reach the quality requirements stated in this study. © 2017 AABB.

  4. Identification of oligo-N-glycolylneuraminic acid residues in mammal-derived glycoproteins by a newly developed immunochemical reagent and biochemical methods.

    Science.gov (United States)

    Sato, C; Kitajima, K; Inoue, S; Inoue, Y

    1998-01-30

    The occurrence of the alpha2-->8-linked oligomeric form of N-glycolylneuraminic acid (oligo-Neu5Gc) residues in mammalian glycoproteins was unequivocally demonstrated using a newly developed anti-oligo/poly-Neu5Gc monoclonal antibody as well as by chemical and biochemical methods. First, the antibody, designated mAb.2-4B, which specifically recognized oligo/poly-Neu5Gc with a degree of polymerization of >2, was developed by establishing a hybridoma cell line from P3U1 myeloma cells fused with splenocytes from an MRL autoimmune mouse immunized with dipalmitoylphosphatidylethanolamine-conjugated oligo/poly-Neu5Gc. Second, oligo-Neu5Gc was shown to occur in glycoproteins derived from pig spleen by Western blot analysis using mAb.2-4B, which was also confirmed by fluorometric high performance liquid chromatographic analysis of the product of periodate oxidation/reduction/acid hydrolysis of the purified glycopeptide fractions and by TLC and 600-MHz 1H NMR spectroscopic analysis of their mild acid hydrolysates. Finally, the ubiquitous occurrence of oligo-Neu5Gc chains as glycoproteinaceous components in Wistar rat tissue was immunochemically indicated. This is the first example demonstrating the diversity in oligo/poly-Sia structure in mammalian glycoproteins, where only poly-N-acetylneuraminic acid is known to occur. Such diversity in oligo/poly-Sia structure also implicates a diverged array of biological functions of this glycan unit in glycoproteins.

  5. Development of a multi-residue analytical method for TBBP-A and PBDEs in various biological matrices using unique reduced size sample

    Energy Technology Data Exchange (ETDEWEB)

    Andre, F.; Cariou, R.; Antignac, J.P.; Le Bizec, B. [Ecole Nationale Veterinaire de Nantes (FR). Laboratoire d' Etudes des Residus et Contaminants dans les Aliments (LABERCA); Debrauwer, L.; Zalko, D. [Institut National de Recherches Agronomiques (INRA), 31-Toulouse (France). UMR 1089 Xenobiotiques

    2004-09-15

    The impact of brominated flame retardants on the environment and their potential risk for animal and human health is a present time concern for the scientific community. Numerous studies related to the detection of tetrabromobisphenol A (TBBP-A) and polybrominated diphenylethers (PBDEs) have been developed over the last few years; they were mainly based on GC-ECD, GC-NCI-MS or GC-EI-HRMS, and recently GC-EI-MS/MS. The sample treatment is usually derived from the analytical methods used for dioxins, but recently some authors proposed the utilisation of solid phase extraction (SPE) cartridges. In this study, a new analytical strategy is presented for the multi-residue analysis of TBBP-A and PBDEs from a unique reduced size sample. The main objective of this analytical development is to be applied for background exposure assessment of French population groups to brominated flame retardants, for which, to our knowledge, no data exist. A second objective is to provide an efficient analytical tool to study the transfer of these contaminants through the environment to living organisms, including degradation reactions and metabolic biotransformations.

  6. Analysis of changes in hardness of a metal surface layer in areas of high stress and methods of determining residual life of parts for mining machines

    Science.gov (United States)

    Zvonarev, I. E.; Ivanov, S. L.

    2016-02-01

    The methodological bases for determining the energy resource of mechanical transmissions details for mining machines are considered. Based on the analysis of the accumulation of damage in metal gears, a method of estimating residual life of coarse-toothed wheels by periodically measuring the hardness of the surface layer of the teeth is justified. The regularities in change of hardness of coarse-tooth gear, conditioned by a change in metal strength properties that take into account the micro- and macromechanisms of plastic and elastic deformation, distortion of the metal crystal lattice with formation and movement of vacancies and dislocations. Experimental setup was built and the results of laboratory experiments are given related to the process of destruction of non-standard samples under different loads. Comparison of dimensions and hardness values of the sample allows concluding that a larger deformation corresponds to a greater increase in hardness, their limit value for the material being in the fracture zone. It is established that the detected changes in the local hardness occurs in areas of increased stresses above the limit of proportionality and the work of fracture forces attributed to dislocations density adjacent to the fracture plane expressed in terms of hardness increment is constant.

  7. Natural sex steroids and their xenobiotic analogs in animal production: growth, carcass quality, pharmacokinetics, metabolism, mode of action, residues, methods, and epidemiology.

    Science.gov (United States)

    Lone, K P

    1997-03-01

    Natural and xenobiotic compounds having sex-related actions have long been used for growth promotion and various changes in carcass quality in meat animals. The first compounds used were synthetic estrogens; however, later on a whole battery of compounds having androgenic, and progestogenic actions have also been involved. In surveying the effects of these compounds in meat-producing animals, it became clear that these drugs increase the growth rate of the treated animals and bring about changes in the carcass that are generally characterized by lower fat content and more lean mass. Extensive studies undertaken in various countries, including the European Economic Community (EEC), have shown that if used according to good husbandry practices, the meat from treated animals does not have excessive amounts of residues compared with the endogenous amount of steroid production in the animals in question and also in human beings. The banning of these compounds in the European community brought a new phenomenon of illegal or black market cocktails. These mixtures of anabolic steroids are injected into the body of the animals rather than implanted in the ears, which is the normal practice in countries where they have not yet been banned. Several screening and confirmatory methods are now available for monitoring programs. However, these programs need excessive resources in terms of manpower, funds, and proper legislation, which in underdeveloped countries is questionable, particularly in the absence of strong scientific evidence for the exercise.

  8. Cycling of grain legume residue nitrogen

    DEFF Research Database (Denmark)

    Jensen, E.S.

    1995-01-01

    Symbiotic nitrogen fixation by legumes is the main input of nitrogen in ecological agriculture. The cycling of N-15-labelled mature pea (Pisum sativum L.) residues was studied during three years in small field plots and lysimeters. The residual organic labelled N declined rapidly during the initial...... management methods in order to conserve grain legume residue N sources within the soil-plant system....

  9. Multi-RELIEF : a method to recognize specificity determining residues from multiple sequence alignments using a Machine-Learning approach for feature weighting

    NARCIS (Netherlands)

    Ye, Kai; Feenstra, K Anton; Heringa, Jaap; Ijzerman, Adriaan P; Marchiori, Elena

    2008-01-01

    MOTIVATION: Identification of residues that account for protein function specificity is crucial, not only for understanding the nature of functional specificity, but also for protein engineering experiments aimed at switching the specificity of an enzyme, regulator or transporter. Available

  10. Studies by nuclear and physico-chemical methods of tissue's metallic contamination located around biomaterials. Toxicity measurements of several biomaterials residual radioactivity

    International Nuclear Information System (INIS)

    Guibert, Geoffroy

    2004-01-01

    Implants used as biomaterials fulfill conditions of functionality, compatibility and occasionally bio-activity. There are four main families of biomaterials: metals and metal alloys, polymers, bio-ceramics and natural materials. Because of corrosion and friction in the human body, implants generate debris. These debris develop different problems: toxicity, inflammatory reactions, prosthetic unsealing by osseous dissolution. Nature, size, morphology and amount of debris are the parameters which have an influence on tissue response. We characterize metallic contamination coming from knee prosthesis into surrounding capsular tissue by depth migration, in vivo behaviours, content, size and nature of debris. The PIXE-RBS and STEM-EDXS methods, that we used, are complementary, especially about characterization scale. Debris contamination distributed in the whole articulation is very heterogeneous. Debris migrate on several thousands μm in tissue. Solid metallic particles, μm, are found in the most polluted samples, for both kinds of alloys TA6V and CrCoMo. In the mean volume analysed by PIXE, the in vivo mass ratios [Ti]/[V] and [Co]/[Cr] confirm the chemical stability of TA6V debris and chemical evolution of CrCoMo debris. Complementary measures of TA6V grains, on a nano-metric scale by STEM-EDXS, show a dissolution of coarse grain (μm) in smaller grains (nm). Locally, TA6V grains of a phase are detected and could indicate a preferential dissolution of β phase (grain boundaries) with dropping of Al and V, both toxic and carcinogenic elements. A thin target protocol development correlates PIXE and histological analysis on the same zone. This protocol allows to locate other pathologies in relationship with weaker metal contamination, μg/g, thanks to the great sensitivity of PIXE method. Harmlessness with respect to the residual radioactivity of several natural or synthetic biomaterials is established, using ultra low background noise γ detection system. (author)

  11. Multi-RELIEF: a method to recognize specificity determining residues from multiple sequence alignments using a Machine-Learning approach for feature weighting.

    Science.gov (United States)

    Ye, Kai; Feenstra, K Anton; Heringa, Jaap; Ijzerman, Adriaan P; Marchiori, Elena

    2008-01-01

    Identification of residues that account for protein function specificity is crucial, not only for understanding the nature of functional specificity, but also for protein engineering experiments aimed at switching the specificity of an enzyme, regulator or transporter. Available algorithms generally use multiple sequence alignments to identify residue positions conserved within subfamilies but divergent in between. However, many biological examples show a much subtler picture than simple intra-group conservation versus inter-group divergence. We present multi-RELIEF, a novel approach for identifying specificity residues that is based on RELIEF, a state-of-the-art Machine-Learning technique for feature weighting. It estimates the expected 'local' functional specificity of residues from an alignment divided in multiple classes. Optionally, 3D structure information is exploited by increasing the weight of residues that have high-weight neighbors. Using ROC curves over a large body of experimental reference data, we show that (a) multi-RELIEF identifies specificity residues for the seven test sets used, (b) incorporating structural information improves prediction for specificity of interaction with small molecules and (c) comparison of multi-RELIEF with four other state-of-the-art algorithms indicates its robustness and best overall performance. A web-server implementation of multi-RELIEF is available at www.ibi.vu.nl/programs/multirelief. Matlab source code of the algorithm and data sets are available on request for academic use.

  12. Evaluation and validation of biochip multi-array technology for the screening of six families of antibiotics in honey according to the European guideline for the validation of screening methods for residues of veterinary medicines.

    Science.gov (United States)

    Gaudin, Valérie; Hedou, Celine; Soumet, Christophe; Verdon, Eric

    2014-01-01

    The main chemicals used against varoa are acaricides, and the antibiotics used for the control of bee bacterial diseases are mainly tetracyclines, streptomycins, sulfonamides and chloramphenicol. No maximum residue limits (MRLs) have been set for any antibiotics in honey. Therefore, in the European Union, minimum recommended concentrations (RC) for the analytical performance of methods to control a certain set of these non-authorised chemicals in honey were published by the European Union Reference Laboratory (EU-RL) in 2007. Concerning the strategy for the control for antibiotic residues in honey, there is still a great need for a cheap and single multi-residue method. Biochip array technology is an innovative assay technology for the multi-analyte screening of biological samples in a rapid and easy-to-use format. A multi-array system, called Evidence Investigator™ (Randox, Crumlin, Co., Antrim, UK), was evaluated in our laboratory. It is a semi-automated biochip system designed for research, clinical applications and veterinary use. A competitive chemiluminescent immunoassay is employed for the detection of antimicrobials. The MicroArray II kit (AM II) dedicated to the screening of six different families of antibiotic residues was validated according to the European guideline for the validation of screening methods for residues of veterinary medicines. The specificity was proven to be very satisfactory, and applicability to different kinds of honey was demonstrated. The detection capabilities (CCβ) of six antibiotic residues were determined and were below the RCs when exist. The AM II kit could detect at least six quinolones, four tetracyclines and three epimers, three aminoglycosides, three macrolides, thiamphenicol, florfenicol and ceftiofur along with one of its stabilised metabolites, the desfuroylceftiofurcysteine disulfide (DCCD).

  13. Automatic prediction of catalytic residues by modeling residue structural neighborhood

    Directory of Open Access Journals (Sweden)

    Passerini Andrea

    2010-03-01

    Full Text Available Abstract Background Prediction of catalytic residues is a major step in characterizing the function of enzymes. In its simpler formulation, the problem can be cast into a binary classification task at the residue level, by predicting whether the residue is directly involved in the catalytic process. The task is quite hard also when structural information is available, due to the rather wide range of roles a functional residue can play and to the large imbalance between the number of catalytic and non-catalytic residues. Results We developed an effective representation of structural information by modeling spherical regions around candidate residues, and extracting statistics on the properties of their content such as physico-chemical properties, atomic density, flexibility, presence of water molecules. We trained an SVM classifier combining our features with sequence-based information and previously developed 3D features, and compared its performance with the most recent state-of-the-art approaches on different benchmark datasets. We further analyzed the discriminant power of the information provided by the presence of heterogens in the residue neighborhood. Conclusions Our structure-based method achieves consistent improvements on all tested datasets over both sequence-based and structure-based state-of-the-art approaches. Structural neighborhood information is shown to be responsible for such results, and predicting the presence of nearby heterogens seems to be a promising direction for further improvements.

  14. Matrix Effect Evaluation and Method Validation of Azoxystrobin and Difenoconazole Residues in Red Flesh Dragon Fruit (Hylocereus polyrhizus) Matrices Using QuEChERS Sample Preparation Methods Followed by LC-MS/MS Determination.

    Science.gov (United States)

    Noegrohati, Sri; Hernadi, Elan; Asviastuti, Syanti

    2018-03-30

    Production of red flesh dragon fruit (Hylocereus polyrhizus) was hampered by Colletotrichum sp. Pre-harvest application of azoxystrobin and difenoconazole mixture is recommended, therefore, a selective and sensitive multi residues analytical method is required in monitoring and evaluating the commodity's safety. LC-MS/MS is a well-established analytical technique for qualitative and quantitative determination in complex matrices. However, this method is hurdled by co-eluted coextractives interferences. This work evaluated the pH effect of acetate buffered and citrate buffered QuEChERS sample preparation in their effectiveness of matrix effect reduction. Citrate buffered QuEChERS proved to produce clean final extract with relative matrix effect 0.4%-0.7%. Method validation of the selected sample preparation followed by LC-MS/MS for whole dragon fruit, flesh and peel matrices fortified at 0.005, 0.01, 0.1 and 1 g/g showed recoveries 75%-119%, intermediate repeatability 2%-14%. The expanded uncertainties were 7%-48%. Based on the international acceptance criteria, this method is valid.

  15. A multi-residue method for pesticides analysis in green coffee beans using gas chromatography-negative chemical ionization mass spectrometry in selective ion monitoring mode.

    Science.gov (United States)

    Pizzutti, Ionara R; de Kok, Andre; Dickow Cardoso, Carmem; Reichert, Bárbara; de Kroon, Marijke; Wind, Wouter; Weber Righi, Laís; Caiel da Silva, Rosselei

    2012-08-17

    In this study, a new gas chromatography-mass spectrometry (GC-MS) method, using the very selective negative chemical ionization (NCI) mode, was developed and applied in combination with a modified acetonitrile-based extraction method (QuEChERS) for the analysis of a large number of pesticide residues (51 pesticides, including isomers and degradation products) in green coffee beans. A previously developed integrated sample homogenization and extraction method for both pesticides and mycotoxins analysis was used. An homogeneous slurry of green milled coffee beans and water (ratio 1:4, w/w) was prepared and extracted with acetonitrile/acetic acid (1%), followed by magnesium sulfate addition for phase separation. Aliquots from this extract could be used directly for LC-MS/MS analysis of mycotoxins and LC-amenable pesticides. For GC-MS analysis, a further clean-up was necessary. C18- and PSA-bonded silica were tested as dispersive solid-phase extraction (d-SPE) sorbents, separate and as a mixture, and the best results were obtained using C18-bonded silica. For the optimal sensitivity and selectivity, GC-MS detection in the NCI-selected ion monitoring (SIM) mode had to be used to allow the fast analysis of the difficult coffee bean matrix. The validation was performed by analyzing recovery samples at three different spike concentrations, 10, 20 and 50 μg kg(-1), with 6 replicates (n=6) at each concentration. Linearity (r(2)) of calibration curves, estimated instrument and method limits of detection and limits of quantification (LOD(i), LOD(m), LOQ(i) and LOQ(m), respectively), accuracy (as recovery %), precision (as RSD%) and matrix effects (%) were determined for each individual pesticide. From the 51 analytes (42 parent pesticides, 4 isomers and 5 degradation products) determined by GC-MS (NCI-SIM), approximately 76% showed average recoveries between 70-120% and 75% and RSD ≤ 20% at the lowest spike concentration of 10 μg kg(-1), the target method LOQ. For the

  16. Mobility of as, Cu, Cr, and Zn from tailings covered with sealing materials using alkaline industrial residues: a comparison between two leaching methods.

    Science.gov (United States)

    Jia, Yu; Maurice, Christian; Öhlander, Björn

    2016-01-01

    Different alkaline residue materials (fly ash, green liquor dregs, and lime mud) generated from the pulp and paper industry as sealing materials were evaluated to cover aged mine waste tailings (<1% sulfur content, primarily pyrite). The mobility of four selected trace elements (Cr, Cu, Zn, and As) was compared based on batch and column leaching studies to assess the effectiveness of these alkaline materials as sealing agents. Based on the leaching results, Cr, Cu, and Zn were immobilized by the alkaline amendments. In the amended tailings in the batch system only As dramatically exceeded the limit values at L/S 10 L/kg. The leaching results showed similar patterns to the batch results, though leached Cr, Cu, and Zn showed higher levels in the column tests than in the batch tests. However, when the columns were compared with the batches, the trend for Cu was opposite for the unamended tailings. By contrast, both batch and column results showed that the amendment caused mobilization of As compared with the unamended tailings in the ash-amended tailings. The amount of As released was greatest in the ash column and decreased from the dregs to the lime columns. The leaching of As at high levels can be a potential problem whenever alkaline materials (especially for fly ash) are used as sealing materials over tailings. The column test was considered by the authors to be a more informative method in remediation of the aged tailings with low sulfur content, since it mimics better actual situation in a field.

  17. Comparison of Some Mechanical and Physical Methods for Measurement of Residual Stresses in Brush-Plated Nickel Hardened Gold and Silver Coatings

    Directory of Open Access Journals (Sweden)

    Harri LILLE

    2016-05-01

    Full Text Available Hard gold and silver are applied in coating owing to their high hardness, good wear and corrosion resistance for engineering application (e.g. on generators slip rings, sliding contacts and small machine parts and are typically plated on copper (mostly, brass and bronze. The studied nickel-hardened gold and silver coatings were brush plated on open thin-walled copper ring substrates. Residual stresses in the coatings were calculated from the curvature changes of the substrates. Biaxial intrinsic residual stresses were also determined by nanoindentation testing and by the X-ray technique. The values of the residual stresses represented tensile stresses and when determined by the techniques used they were comparable within a maximum limit of measurement uncertainty. These stresses relax; the dependence of relaxation time was approximated by a linear-fractional function.DOI: http://dx.doi.org/10.5755/j01.ms.22.1.7439

  18. Study of field assessment methods and worker risks for processing alternatives to support principles for FUSRAP waste materials. Part 1: Treatment methods and comparative risks of thorium removal from waste residues

    Energy Technology Data Exchange (ETDEWEB)

    Porter, R.D.; Hamby, D.M.; Martin, J.E.

    1997-07-01

    This study was done to examine the risks of remediation and the effectiveness of removal methods for thorium and its associated radioactive decay products from various soils and wastes associated with DOE`s Formerly Utilized Sites Remedial Action Program (FUSRAP). Its purpose was to provide information to the Environmental Management Advisory Board`s FUSRAP Committee for use in its deliberation of guiding principles for FUSRAP sites, in particular the degree to which treatment should be considered in the FUSRAP Committee`s recommendations. Treatment of FUSRAP wastes to remove thorium could be beneficial to management of lands that contain thorium if such treatment were effective and cost efficient. It must be recognized, however, that treatment methods invariably require workers to process residues and waste materials usually with bulk handling techniques. These processes expose workers to the radioactivity in the materials, therefore, workers would incur radiological risks in addition to industrial accident risks. An important question is whether the potential reduction of future radiological risks to members of the public justifies the risks that are incurred by remediation workers due to handling materials. This study examines, first, the effectiveness of treatment and then the risks that would be associated with remediation. Both types of information should be useful for decisions on whether and how to apply thorium removal methods to FUSRAP waste materials.

  19. Study of field assessment methods and worker risks for processing alternatives to support principles for FURSRAP waste materials. Part 1: Treatment methods and comparative risks of thorium removal from waste residues

    International Nuclear Information System (INIS)

    Porter, R.D.; Hamby, D.M.; Martin, J.E.

    1997-07-01

    This study was done to examine the risks of remediation and the effectiveness of removal methods for thorium and its associated radioactive decay products from various soils and wastes associated with DOE's Formerly Utilized Sites Remedial Action Program (FUSRAP). Its purpose was to provide information to the Environmental Management Advisory Board's FUSRAP Committee for use in its deliberation of guiding principles for FUSRAP sites, in particular the degree to which treatment should be considered in the FUSRAP Committee's recommendations. Treatment of FUSRAP wastes to remove thorium could be beneficial to management of lands that contain thorium if such treatment were effective and cost efficient. It must be recognized, however, that treatment methods invariably require workers to process residues and waste materials usually with bulk handling techniques. These processes expose workers to the radioactivity in the materials, therefore, workers would incur radiological risks in addition to industrial accident risks. An important question is whether the potential reduction of future radiological risks to members of the public justifies the risks that are incurred by remediation workers due to handling materials. This study examines, first, the effectiveness of treatment and then the risks that would be associated with remediation. Both types of information should be useful for decisions on whether and how to apply thorium removal methods to FUSRAP waste materials

  20. Residue determination of two co-administered antibacterial agents--cephalexin and colistin--in calf tissues using high-performance liquid chromatography and microbiological methods.

    Science.gov (United States)

    Leroy, P; Decolin, D; Nicolas, S; Archimbault, P; Nicolas, A

    1989-01-01

    Residues of two antibacterial agents, cephalexin and colistin, co-administered by intramuscular injection to calves, were quantified in four different tissues (muscle, fat, liver and kidney) by column switching HPLC and by a microbiological method. For cephalexin assay, tissue samples with cephradin as internal standard were homogenized in a 5% trichloroacetic acid solution and filtrates were injected onto a concentration precolumn filled with LiChroprep RP-18 (25-40 microns). A clean-up step was incorporated by flowing a mobile phase (methanol-0.01 M phosphate buffer (pH 3.0); 15:85, v/v) through the enrichment column before elution on a LiChrospher RP-18e (5 microns) column with a methanol-phosphate buffer (30:70, v/v) at a flow rate of 1 ml min-1. Spectrometric detection was at 260 nm. An additional "off-line" washing step of extracts with methylene chloride was operated to achieve higher selectivity in the case of liver and kidney samples. The limit for quantitative assay was 0.045 micrograms g-1 with relative standard deviations in the range 5-8% and recoveries within 70%. For microbiological assay of colistin, samples were homogenized in 0.1 M hydrochloric acid-acetonitrile mixtures (3:1, v/v, for kidney and liver; 3:2, v/v, for fat and muscle). The supernatants were assayed by the cylinder plate method after evaporation to dryness under vacuum. Bordetella bronchiseptica ATCC 4617 was chosen as test organism. After a 3-h diffusion step at room temperature, the medium was incubated at 37 degrees C for 18 h and then the diameter of the growth inhibition zones was measured. Sensitivity reached 0.10-0.15 micrograms g-1. Results from the analysed samples over a 7-28 day period after drug administration show that no cephalexin was found at concentrations higher than the quantitation limit in the four test tissues and that colistin was found in muscle (injection site only) for 15 days and in kidney for 21 days.

  1. Bioenergy from sisal residues

    Energy Technology Data Exchange (ETDEWEB)

    Jungersen, G. [Dansk Teknologisk Inst. (Denmark); Kivaisi, A.; Rubindamayugi, M. [Univ. of Dar es Salaam (Tanzania, United Republic of)

    1998-05-01

    The main objectives of this report are: To analyse the bioenergy potential of the Tanzanian agro-industries, with special emphasis on the Sisal industry, the largest producer of agro-industrial residues in Tanzania; and to upgrade the human capacity and research potential of the Applied Microbiology Unit at the University of Dar es Salaam, in order to ensure a scientific and technological support for future operation and implementation of biogas facilities and anaerobic water treatment systems. The experimental work on sisal residues contains the following issues: Optimal reactor set-up and performance; Pre-treatment methods for treatment of fibre fraction in order to increase the methane yield; Evaluation of the requirement for nutrient addition; Evaluation of the potential for bioethanol production from sisal bulbs. The processing of sisal leaves into dry fibres (decortication) has traditionally been done by the wet processing method, which consumes considerable quantities of water and produces large quantities of waste water. The Tanzania Sisal Authority (TSA) is now developing a dry decortication method, which consumes less water and produces a waste product with 12-15% TS, which is feasible for treatment in CSTR systems (Continously Stirred Tank Reactors). (EG)

  2. Numerical Analysis of Residual Stress and Distortion Use Finite Element Method on Inner Bottom Construction of Geomarin IV Survey Ship with Welding Sequence Variations

    Science.gov (United States)

    Syahroni, N.; Hartono, A. B. W.; Murtedjo, M.

    2018-03-01

    In the ship fabrication industry, welding is the most critical stage. If the quality of welding on ship fabrication is not good, then it will affect the strength and overall appearance of the structure. One of the factors that affect the quality of welding is residual stress and distortion. In this research welding simulation is performed on the inner bottom construction of Geomarin IV Ship Survey using shell element and has variation to welding sequence. In this study, welding simulations produced peak temperatures at 2490 K at variation 4. While the lowest peak temperature was produced by variation 2 with a temperature of 2339 K. After welding simulation, it continued simulating residual stresses and distortion. The smallest maximum tensile residual stress found in the inner bottom construction is 375.23 MPa, and the maximum tensile pressure is -20.18 MPa. The residual stress is obtained from variation 3. The distortion occurring in the inner bottom construction for X=720 mm is 4.2 mm and for X=-720 mm, the distortion is 4.92 mm. The distortion is obtained from the variation 3. Near the welding area, distortion value reaches its minimum point. This is because the stiffeners in the form of frames serves as anchoring.

  3. Characterization and elimination of undesirable protein residues in plant cell walls for enhancing lignin analysis by solution-state 2D gel-NMR methods

    Science.gov (United States)

    Proteins exist in every plant cell wall. Certain protein residues interfere with lignin characterization and quantification. The current solution-state 2D-NMR technique (gel-NMR) for whole plant cell wall structural profiling provides detailed information regarding cell walls and proteins. However, ...

  4. Validation of a standard field test method in four countries to assess the toxicity of residues in dung of cattle treated with veterinary medical products

    NARCIS (Netherlands)

    Floate, Kevin D.; Düring, Rolf Alexander; Hanafi, Jamal; Jud, Priska; Lahr, Joost; Lumaret, Jean Pierre; Scheffczyk, Adam; Tixier, Thomas; Wohde, Manuel; Römbke, Jörg; Sautot, Lucille; Blanckenhorn, Wolf U.

    2016-01-01

    Registration of veterinary medical products includes the provision that field tests may be required to assess potential nontarget effects associated with the excretion of product residues in dung of treated livestock (phase II, tier B testing). However, regulatory agencies provide no guidance on

  5. Evaluation of residue-residue contact prediction in CASP10

    KAUST Repository

    Monastyrskyy, Bohdan

    2013-08-31

    We present the results of the assessment of the intramolecular residue-residue contact predictions from 26 prediction groups participating in the 10th round of the CASP experiment. The most recently developed direct coupling analysis methods did not take part in the experiment likely because they require a very deep sequence alignment not available for any of the 114 CASP10 targets. The performance of contact prediction methods was evaluated with the measures used in previous CASPs (i.e., prediction accuracy and the difference between the distribution of the predicted contacts and that of all pairs of residues in the target protein), as well as new measures, such as the Matthews correlation coefficient, the area under the precision-recall curve and the ranks of the first correctly and incorrectly predicted contact. We also evaluated the ability to detect interdomain contacts and tested whether the difficulty of predicting contacts depends upon the protein length and the depth of the family sequence alignment. The analyses were carried out on the target domains for which structural homologs did not exist or were difficult to identify. The evaluation was performed for all types of contacts (short, medium, and long-range), with emphasis placed on long-range contacts, i.e. those involving residues separated by at least 24 residues along the sequence. The assessment suggests that the best CASP10 contact prediction methods perform at approximately the same level, and comparably to those participating in CASP9.

  6. Marine Tar Residues: a Review.

    Science.gov (United States)

    Warnock, April M; Hagen, Scott C; Passeri, Davina L

    Marine tar residues originate from natural and anthropogenic oil releases into the ocean environment and are formed after liquid petroleum is transformed by weathering, sedimentation, and other processes. Tar balls, tar mats, and tar patties are common examples of marine tar residues and can range in size from millimeters in diameter (tar balls) to several meters in length and width (tar mats). These residues can remain in the ocean environment indefinitely, decomposing or becoming buried in the sea floor. However, in many cases, they are transported ashore via currents and waves where they pose a concern to coastal recreation activities, the seafood industry and may have negative effects on wildlife. This review summarizes the current state of knowledge on marine tar residue formation, transport, degradation, and distribution. Methods of detection and removal of marine tar residues and their possible ecological effects are discussed, in addition to topics of marine tar research that warrant further investigation. Emphasis is placed on benthic tar residues, with a focus on the remnants of the Deepwater Horizon oil spill in particular, which are still affecting the northern Gulf of Mexico shores years after the leaking submarine well was capped.

  7. Residual DPCM about Motion Compensated Residual Signal for H.264 Lossless Coding

    Science.gov (United States)

    Han, Ki-Hun; Rao, Kamisetty R.; Lee, Yung-Lyul

    In this letter, a new Inter lossless coding method based on a residual DPCM (Differential Pulse Code Modulation) is proposed to improve compression ratio in the H.264 standard. Since the spatial correlation in a residual block can be further exploited among the residual signals after motion estimation/compensation, horizontal or vertical DPCM in the residual signals can be applied to further reduce the magnitudes of the residual signals. The proposed method reduces the average bitrates of 3.5% compared with the Inter lossless coding of the H.264 standard.

  8. A novel method to depurate β-lactam antibiotic residues by administration of a broad-spectrum β-lactamase enzyme in fish tissues

    Directory of Open Access Journals (Sweden)

    Young-Sik Choe

    2016-12-01

    Full Text Available Abstract As a novel strategy to remove β-lactam antibiotic residues from fish tissues, utilization of β-lactamase, enzyme that normally degrades β-lactam structure-containing drugs, was explored. The enzyme (TEM-52 selectively degraded β-lactam antibiotics but was completely inactive against tetracycline-, quinolone-, macrolide-, or aminoglycoside-structured antibacterials. After simultaneous administration of the enzyme with cefazolin (a β-lactam antibiotic to the carp, significantly lowered tissue cefazolin levels were observed. It was confirmed that the enzyme successfully reached the general circulation after intraperitoneal administration, as the carp serum obtained after enzyme injection could also degrade cefazolin ex vivo. These results suggest that antibiotics-degrading enzymes can be good candidates for antibiotic residue depuration.

  9. Design and validation of a new method to detect and quantify residual host cell DNA in human recombinant erythropoietin (rEPO).

    Science.gov (United States)

    Zamanian, Shima; Mohammadi-Yeganeh, Samira; Kia, Vahid; Kaghazian, Hooman; Paryan, Mahdi

    2017-10-21

    During the purification of human recombinant erythropoietin (rEPO) from host cells, residual DNA may remain in final products. This contamination is a risk factor for patients and may result in the inactivation of some tumor suppressor genes or activation of oncogenes if its concentration is more than the standard defined by WHO. Based on WHO's criteria, acceptable level of residual DNA in biopharmaceuticals is less than 10-100 pg/dose. In this study, we have designed a sensitive and specific quantitative real-time polymerase chain reaction (PCR) assay for the detection of residual DNA in human rEPO products. All reported sequences of CHO's GAPDH gene were retrieved from GenBank, and a multiple alignment was performed using Mega 6 software to find conserved regions of the gene. Primers and probe were designed by AlleleID7 software for the highly conserved region. Quantitative real-time PCR showed an R 2 value more than 0.99 and the efficiency equal to 101% indicating a highly accurate and efficiency of the reaction, respectively. Based on the standard curve, the limit of detection of the assay was determined to be 10 copies/µL (0.00967 fg/µL). In addition, the inter- and intra-assay of the test were determined to be 1.14% and 0.65%, respectively, which are in acceptable range according to the WHO's guidelines.

  10. The validation of an analytical method for sulfentrazone residue determination in soil using liquid chromatography and a comparison of chromatographic sensitivity to millet as a bioindicator species.

    Science.gov (United States)

    de Oliveira, Marcelo Antonio; Pires, Fábio Ribeiro; Ferraço, Mariana; Belo, Alessandra Ferreira

    2014-07-28

    Commonly used herbicides, such as sulfentrazone, pose the risk of soil contamination due to their persistence, bioaccumulation and toxicity. Phytoremediation by green manure species has been tested using biomarkers, but analytical data are now required to confirm the extraction of sulfentrazone from soil. Thus, the present work was carried out to analyze sulfentrazone residues in soil based on liquid chromatography with a comparison of these values to the sensitivity of the bioindicator Pennisetum glaucum. The soil samples were obtained after cultivation of Crotalaria juncea and Canavalia ensiformis at four seeding densities and with three doses of sulfentrazone. The seedlings were collected into pots, at two different depths, after 75 days of phytoremediator sowing and then were used to determine the herbicide persistence in the soil. A bioassay with P. glaucum was carried out in the same pot. High-performance liquid chromatography (HPLC), using UV-diode array detection (HPLC/UV-DAD), was used to determine the herbicide residues. The HPLC determination was optimized and validated according to the parameters of precision, accuracy, linearity, limit of detection and quantification, robustness and specificity. The bioindicator P. glaucum was more sensitive to sulfentrazone than residue determination by HPLC. Changes in sulfentrazone concentration caused by green manure phytoremediation were accurately identified by the bioindicator. However, a true correlation between the size of the species and the analyte content was not identified.

  11. The Validation of an Analytical Method for Sulfentrazone Residue Determination in Soil Using Liquid Chromatography and a Comparison of Chromatographic Sensitivity to Millet as a Bioindicator Species

    Directory of Open Access Journals (Sweden)

    Marcelo Antonio de Oliveira

    2014-07-01

    Full Text Available Commonly used herbicides, such as sulfentrazone, pose the risk of soil contamination due to their persistence, bioaccumulation and toxicity. Phytoremediation by green manure species has been tested using biomarkers, but analytical data are now required to confirm the extraction of sulfentrazone from soil. Thus, the present work was carried out to analyze sulfentrazone residues in soil based on liquid chromatography with a comparison of these values to the sensitivity of the bioindicator Pennisetum glaucum. The soil samples were obtained after cultivation of Crotalaria juncea and Canavalia ensiformis at four seeding densities and with three doses of sulfentrazone. The seedlings were collected into pots, at two different depths, after 75 days of phytoremediator sowing and then were used to determine the herbicide persistence in the soil. A bioassay with P. glaucum was carried out in the same pot. High-performance liquid chromatography (HPLC, using UV-diode array detection (HPLC/UV-DAD, was used to determine the herbicide residues. The HPLC determination was optimized and validated according to the parameters of precision, accuracy, linearity, limit of detection and quantification, robustness and specificity. The bioindicator P. glaucum was more sensitive to sulfentrazone than residue determination by HPLC. Changes in sulfentrazone concentration caused by green manure phytoremediation were accurately identified by the bioindicator. However, a true correlation between the size of the species and the analyte content was not identified.

  12. Residual micro-stress distributions in heat-pressed ceramic on zirconia and porcelain-fused to metal systems: Analysis by FIB-DIC ring-core method and correlation with fracture toughness.

    Science.gov (United States)

    Sebastiani, M; Massimi, F; Merlati, G; Bemporad, E

    2015-11-01

    The production of fixed partial dentures (FPDs) induces complex residual stress profiles, due to both the thermal expansion coefficient mismatch between the veneering ceramic and the framework and to the thermal gradients occurring during the final cooling. Detailed knowledge of residual stress distributions in the veneering ceramics is important to understand the interface phenomena with the framework and the consequences of the different firing systems. The first objective of this study was to analyse the residual stress distribution in heat-pressed ceramic on zirconia core with micrometer spatial resolution, with also a focus on the stress at the interface versus porcelain-fused-to-metal samples. The second purpose was to correlate the residual stress with the fracture toughness. The micron-scale focused ion beam (FIB) ring-core method was used to map the residual stress over the cross-sections of the veneering ceramics. The methodology is based on FIB micro-milling of annular trenches, combined with high-resolution in situ scanning electron microscope (SEM) imaging, a full field strain analysis by digital image correlation (DIC) and numerical models for residual stress calculation. Fracture toughness was evaluated by using high load Vickers indentation and hardness/modulus were measured by nanoindentation testing also across the interfaces. Both prosthetic systems showed a compressive stress at the ceramic surface on a micron-scale. The stress profile for porcelain fused to metal (PFM) showed a transition to tensile stress at the half of the layer, whilst the stress in proximity of the interface was more compressive in both the cases. Residual stress on a micron scale are higher in magnitude than the corresponding macro-scale values reported in the literature, due to the stress relaxation given, at larger scales, by micro-voids and cracks. The stress field was directly correlated with the indentation fracture toughness, which was higher in those areas where the

  13. Deep residual networks of residual networks for image super-resolution

    Science.gov (United States)

    Wei, Xueqi; Yang, Fumeng; Wu, Congzhong

    2017-11-01

    Single image super-resolution (SISR), which aims at obtaining a high-resolution image from a single low-resolution image, is a classical problem in computer vision. In this paper, we address this problem based on a deep learning method with residual learning in an end-to-end manner. We propose a novel residual-network architecture, Residual networks of Residual networks (RoR), to promote the learning capability of residual networks for SISR. In residual network, the signal can be directly propagated from one unit to any other units in both forward and backward passes when using identity mapping as the skip connections. Based on it, we add level-wise connections upon original residual networks, to dig the optimization ability of residual networks. Our experiments demonstrate the effectiveness and versatility of RoR, it can get a faster convergence speed and gain higher resolution accuracy from considerably increased depth.

  14. Influência do aquecimento sobre diferentes métodos de titulação de SO2 residual em camarões Litopenaeus vannamei (Boone, 1931 = Influence of heating under different titration methods of residual SO2 on shrimps Litopenaeus vannamei (Boone, 1931

    Directory of Open Access Journals (Sweden)

    Karla Patrícia Brito de Araújo Vieira

    2008-01-01

    Full Text Available O metabissulfito de sódio é o conservante mais aplicado na carcinicultura, com uso amparado em legislações vigentes no país, todavia, seu resíduo, dióxido de enxofre (SO2, em concentrações altas, pode provocar reações adversas à saúde. Este estudo foidesenvolvido com a finalidade de observar a influência do aquecimento sob diferentes métodos de titulação de SO2 residual em camarões Litopenaeus vannamei. Os camarões foram submetidos a nove concentrações de metabissulfito de sódio e avaliados com diferentesmétodos de detecção de SO2. O método da titulação Adolfo Lutz adaptado apresentou grande sensibilidade para detecção de SO2 residual. O método da titulação iodométrica com aquecimento possibilitou a detecção de maiores níveis de SO2, quando comparado aométodo sem o aquecimento. O aquecimento interferiu negativamente no método da fita reativa. Conclui-se que o aquecimento influenciou positivamente a titulação iodométrica, não ocorrendo o mesmo com a fita reativa.Sodium metabisulfite is the most applied preservative in shrimp culture, with its use supported by current legislation; however, its residue, sulfur dioxide (SO2, in high concentrations can provoke adverse health reactions. This study evaluated the influence of heating under different methods of residual SO2 titration in Litopenaeus vannamei. Shrimps were treated with nine concentrations of sodium metabisulfite and evaluated by different methods of SO2 titration. The adapted Adolfo Lutz titration method presented the highest sensitivity for the detection of SO2. The method of iodometric titration with heating made possible the detention ofhigher levels of SO2, when compared to the same method without heating. The heating influenced negatively on the reactive ribbon method. It is concluded that the heating influenced positively on the iodometric titration, as opposed to the reactive ribbon.

  15. Single-laboratory validation of an LC-MS/MS method for determining florfenicol (FF) and florfenicol amine (FFA) residues in chicken feathers and application to a residue-depletion study.

    Science.gov (United States)

    Cornejo, J; Pokrant, E; Riquelme, R; Briceño, C; Maddaleno, A; Araya-Jordán, C; San Martin, B

    2017-04-01

    A suitable analytical method is required to study the behaviour of florfenicol (FF) and its metabolite florfenicol amine (FFA) in broiler's feathers. An LC-MS/MS method was developed, assessed and intra-laboratory-validated for FF and FFA analyses. We chose cloramphenicol-d 5 as an internal standard, acetone as a solvent for the extraction of the analytes and dichloromethane for the clean-up. Through LC-MS/MS analysis, we established a detection limit of 20 μg kg - 1 , as well as calculated quantification limits of 24.4 and 24.5 μg kg - 1 for FF and FFA, respectively. Validation parameters such as linearity, recovery and precision were calculated following Commission Decision 2002/657/EC. For linearity, all standard curves showed a standard coefficient greater than 0.99. Recoveries ranged from 99% to 102% for all studied concentrations. The results show that this analytical method is precise and reliable. For the depletion study, 64 Ross 308 broilers were treated with a therapeutic dosage of 10% FF during 5 consecutive days and their feathers were then analysed. Samples were drawn on days 5, 10, 15, 20, 25, 30, 35 and 40 post-treatments. As for the control group, 16 broiler chickens were raised under the same regime. Throughout the whole study, the detected concentrations of FF and FFA in feather samples were above 100 µg kg - 1 . In fact, even on day 30 post-treatment we detected concentrations of 221.8 and 28.8 µg kg - 1 for FF and FFA, respectively. Based on these results, we conclude that these analytes will persist for a long time and will deplete slowly in feathers of treated broiler chickens.

  16. Residual stress in polyethylene pipes

    Czech Academy of Sciences Publication Activity Database

    Poduška, Jan; Hutař, Pavel; Kučera, J.; Frank, A.; Sadílek, J.; Pinter, G.; Náhlík, Luboš

    2016-01-01

    Roč. 54, SEP (2016), s. 288-295 ISSN 0142-9418 R&D Projects: GA MŠk LM2015069; GA MŠk(CZ) LQ1601 Institutional support: RVO:68081723 Keywords : polyethylene pipe * residual stress * ring slitting method * lifetime estimation Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.464, year: 2016

  17. Development of a new method for the determination of residues of the neonicotinoid insecticide imidacloprid in juvenile chinook (Oncorhynchus tshawytscha) using ELISA detection.

    Science.gov (United States)

    Frew, John A; Grue, Christian E

    2012-03-01

    The neonicotinoid insecticide imidacloprid (IMI) has been proposed as an alternative to carbaryl for controlling indigenous burrowing shrimp on commercial oyster beds in Willapa Bay and Grays Harbor, Washington. A focus of concern over the use of this insecticide in an aquatic environment is the potential for adverse effects from exposure to non-target species residing in the Bay, such as juvenile Chinook (Oncorhynchus tshawytscha) and cutthroat trout (O. clarki). Federal registration and State permiting approval for the use of IMI will require confirmation that the compound does not adversely impact these salmonids following field applications. This will necessitate an environmental monitoring program for evaluating exposure in salmonids following the treatment of beds. Quantification of IMI residues in tissue can be used for determining salmonid exposure to the insecticide. Refinement of an existing protocol using liquid-chromatography mass spectrometry (LC-MS) detection would provide the low limits of quantification, given the relatively small tissue sample sizes, necessary for determining exposure in individual fish. Such an approach would not be viable for the environmental monitoring effort in Willapa Bay and Grays Harbor due to the high costs associated with running multiple analyses, however. A new sample preparation protocol was developed for use with a commercially available enzyme-linked immunosorbent assay (ELISA) for the quantification of IMI, thereby providing a low-cost alternative to LC-MS for environmental monitoring in Willapa Bay and Grays Harbor. Extraction of the analyte from the salmonid brain tissue was achieved by Dounce homogenization in 4.0 mL of 20.0 mM Triton X-100, followed by a 6 h incubation at 50-55 °C. Centrifugal ultrafiltration and reversed phase solid phase extraction were used for sample cleanup. The limit of quantification for an average 77.0 mg whole brain sample was calculated at 18.2 μg kg(-1) (ppb) with an average

  18. Development of a new method for the determination of residues of the neonictinoid insecticide imidacloprid in juvenile Chinook (Oncorhynchus tyshawytscha) using ELISA detection

    Science.gov (United States)

    Frew, John A.; Grue, Christian E.

    2012-01-01

    The neonicotinoid insecticide imidacloprid (IMI) has been proposed as an alternative to carbaryl for controlling indigenous burrowing shrimp on commercial oyster beds in Willapa Bay and Grays Harbor, Washington. A focus of concern over the use of this insecticide in an aquatic environment is the potential for adverse effects from exposure to non-target species residing in the Bay, such as juvenile Chinook (Oncorhynchus tshawytscha) and cutthroat trout (O. clarki). Federal registration and State permiting approval for the use of IMI will require confirmation that the compound does not adversely impact these salmonids following field applications. This will necessitate an environmental monitoring program for evaluating exposure in salmonids following the treatment of beds. Quantification of IMI residues in tissue can be used for determining salmonid exposure to the insecticide. Refinement of an existing protocol using liquid-chromatography mass spectrometry (LC-MS) detection would provide the low limits of quantification, given the relatively small tissue sample sizes, necessary for determining exposure in individual fish. Such an approach would not be viable for the environmental monitoring effort in Willapa Bay and Grays Harbor due to the high costs associated with running multiple analyses, however. A new sample preparation protocol was developed for use with a commercially available enzyme-linked immunosorbent assay (ELISA) for the quantification of IMI, thereby providing a low-cost alternative to LC-MS for environmental monitoring in Willapa Bay and Grays Harbor. Extraction of the analyte from the salmonid brain tissue was achieved by Dounce homogenization in 4.0 mL of 20.0 mM Triton X-100, followed by a 6 h incubation at 50–55 °C. Centrifugal ultrafiltration and reversed phase solid phase extraction were used for sample cleanup. The limit of quantification for an average 77.0 mg whole brain sample was calculated at 18.2 μg kg-1 (ppb) with an average

  19. Development and validation of a multi-residue method for the detection of a wide range of hormonal anabolic compounds in hair using gas chromatography-tandem mass spectrometry

    International Nuclear Information System (INIS)

    Rambaud, Lauriane; Monteau, Fabrice; Deceuninck, Yoann; Bichon, Emmanuelle; Andre, Francois; Le Bizec, Bruno

    2007-01-01

    The monitoring of anabolic steroid residues in hair is undoubtedly one of the most efficient strategies to demonstrate the long-term administration of these molecules in meat production animals. A multi-residue sample preparation procedure was developed and validated for 28 steroids. A 100 mg hair sample was grinded into powder and extracted at 50 deg. C with methanol. After acidic hydrolysis and extraction with ethyl acetate, phenolsteroids, such as estrogens, resorcyclic acid lactones and stilbens in one hand, are separated from androgens and progestagens in the other hand. Solid phase extractions were performed before applying a specific derivatisation for each compound sub-group. Detection and identification were achieved using gas chromatography-tandem mass spectrometry with acquisition in the selected reaction monitoring mode after electron ionisation. The method was validated according to the 2002/657/EC guideline. Decision limits (CCα) for main steroids were in the 0.1-10 μg kg -1 range

  20. Determination of 17 organophosphate pesticide residues in mango by modified QuEChERS extraction method using GC-NPD/GC-MS and hazard index estimation in Lucknow, India.

    Directory of Open Access Journals (Sweden)

    Ashutosh K Srivastava

    Full Text Available A total of 162 samples of different varieties of mango: Deshehari, Langra, Safeda in three growing stages (Pre-mature, Unripe and Ripe were collected from Lucknow, India, and analyzed for the presence of seventeen organophosphate pesticide residues. The QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe method of extraction coupled with gas chromatography was validated for pesticides and qualitatively confirmed by gas chromatography-mass spectrometry. The method was validated with different concentrations of mixture of seventeen organophosphate pesticides (0.05, 0.10, 0.50 mg kg(-1 in mango. The average recovery varied from 70.20% to 95.25% with less than 10% relative standard deviation. The limit of quantification of different pesticides ranged from 0.007 to 0.033 mg kg(-1. Out of seventeen organophosphate pesticides only malathion and chlorpyriphos were detected. Approximately 20% of the mango samples have shown the presence of these two pesticides. The malathion residues ranged from ND-1.407 mg kg(-1 and chlorpyriphos ND-0.313 mg kg(-1 which is well below the maximum residues limit (PFA-1954. In three varieties of mango at different stages from unpeeled to peeled sample reduction of malathion and chlorpyriphos ranged from 35.48%-100% and 46.66%-100% respectively. The estimated daily intake of malathion ranged from 0.032 to 0.121 µg kg(-1 and chlorpyriphos ranged from zero to 0.022 µg kg(-1 body weight from three different stages of mango. The hazard indices ranged from 0.0015 to 0.0060 for malathion and zero to 0.0022 for chlorpyriphos. It is therefore indicated that seasonal consumption of these three varieties of mango may not pose any health hazards for the population of Lucknow, city, India because the hazard indices for malathion and chlorpyriphos residues were below to one.

  1. Actinide recovery from pyrochemical residues

    International Nuclear Information System (INIS)

    Avens, L.R.; Clifton, D.G.; Vigil, A.R.

    1985-05-01

    We demonstrated a new process for recovering plutonium and americium from pyrochemical waste. The method is based on chloride solution anion exchange at low acidity, or acidity that eliminates corrosive HCl fumes. Developmental experiments of the process flow chart concentrated on molten salt extraction (MSE) residues and gave >95% plutonium and >90% americium recovery. The recovered plutonium contained 6 2- from high-chloride low-acid solution. Americium and other metals are washed from the ion exchange column with lN HNO 3 -4.8M NaCl. After elution, plutonium is recovered by hydroxide precipitation, and americium is recovered by NaHCO 3 precipitation. All filtrates from the process can be discardable as low-level contaminated waste. Production-scale experiments are in progress for MSE residues. Flow charts for actinide recovery from electro-refining and direct oxide reduction residues are presented and discussed

  2. Residual stresses around Vickers indents

    International Nuclear Information System (INIS)

    Pajares, A.; Guiberteau, F.; Steinbrech, R.W.

    1995-01-01

    The residual stresses generated by Vickers indentation in brittle materials and their changes due to annealing and surface removal were studied in 4 mol% yttria partially stabilized zirconia (4Y-PSZ). Three experimental methods to gain information about the residual stress field were applied: (i) crack profile measurements based on serial sectioning, (ii) controlled crack propagation in post indentation bending tests and (iii) double indentation tests with smaller secondary indents located around a larger primary impression. Three zones of different residual stress behavior are deduced from the experiments. Beneath the impression a crack free spherical zone of high hydrostatic stresses exists. This core zone is followed by a transition regime where indentation cracks develop but still experience hydrostatic stresses. Finally, in an outward third zone, the crack contour is entirely governed by the tensile residual stress intensity (elastically deformed region). Annealing and surface removal reduce this crack driving stress intensity. The specific changes of the residual stresses due to the post indentation treatments are described and discussed in detail for the three zones

  3. Improvement and extension to new analytes of a multi-residue method for the determination of pesticides in cereals and dry animal feed using gas chromatography-tandem quadrupole mass spectrometry revisited.

    Science.gov (United States)

    Walorczyk, Stanisław; Drożdżyński, Dariusz

    2012-08-17

    This article describes a substantially improved multi-residue method for the determination of a large number of pesticides in cereal samples (wheat, rye, barley, oats, maze, buckwheat etc.) and various animal feeds. The sample preparation method and the GC-MS/MS acquisition method were modified to accommodate new complex cereal and feed matrices and to extend the existing analytical scope to 167 pesticides. The co-extractives were reduced by the joint use of primary secondary amine (PSA) and octadecyl (C18), 75 mg and 50 mg/1 mL of acetonitrile extract, in the presence of MgSO(4), and thus the optimal recovery and analytical selectivity were obtained simultaneously. The new cleanup procedure was faster and easier to handle than our previously applied cleanup procedure. The overall recoveries of the pesticides from buckwheat and rye at the three spiking levels of 0.01, 0.05 and 0.25 mg kg(-1) were 96 ± 9% with relative standard deviations of 10 ± 4% on average. At the lowest spiking level of 0.01 mg kg(-1), 137 of 167 pesticide residues (82%) fulfilled the validation criteria with recoveries in the range of 70-120% and RSDs less or equal 20% whereas in the previous approach it was 93 out of 140 analytes (66%). The developed method was implemented in a routine analysis of approximately 900 real samples, providing an increased scope of the analysis, improved analytical performance parameters and improved ruggedness versus the previous approach. A total of 17% analyzed samples contained pesticide residues. There were 24 different compounds encountered in the samples, of which pirimiphos-methyl, tebuconazole, deltamethrin, and chlorpyrifos-methyl were the most frequent ones. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Parallel iterative solvers and preconditioners using approximate hierarchical methods

    Energy Technology Data Exchange (ETDEWEB)

    Grama, A.; Kumar, V.; Sameh, A. [Univ. of Minnesota, Minneapolis, MN (United States)

    1996-12-31

    In this paper, we report results of the performance, convergence, and accuracy of a parallel GMRES solver for Boundary Element Methods. The solver uses a hierarchical approximate matrix-vector product based on a hybrid Barnes-Hut / Fast Multipole Method. We study the impact of various accuracy parameters on the convergence and show that with minimal loss in accuracy, our solver yields significant speedups. We demonstrate the excellent parallel efficiency and scalability of our solver. The combined speedups from approximation and parallelism represent an improvement of several orders in solution time. We also develop fast and paralellizable preconditioners for this problem. We report on the performance of an inner-outer scheme and a preconditioner based on truncated Green`s function. Experimental results on a 256 processor Cray T3D are presented.

  5. Rapid determination of residues of pesticides in honey by µGC-ECD and GC-MS/MS: Method validation and estimation of measurement uncertainty according to document No. SANCO/12571/2013.

    Science.gov (United States)

    Paoloni, Angela; Alunni, Sabrina; Pelliccia, Alessandro; Pecorelli, Ivan

    2016-01-01

    A simple and straightforward method for simultaneous determination of residues of 13 pesticides in honey samples (acrinathrin, bifenthrin, bromopropylate, cyhalothrin-lambda, cypermethrin, chlorfenvinphos, chlorpyrifos, coumaphos, deltamethrin, fluvalinate-tau, malathion, permethrin and tetradifon) from different pesticide classes has been developed and validated. The analytical method provides dissolution of honey in water and an extraction of pesticide residues by n-Hexane followed by clean-up on a Florisil SPE column. The extract was evaporated and taken up by a solution of an injection internal standard (I-IS), ethion, and finally analyzed by capillary gas chromatography with electron capture detection (GC-µECD). Identification for qualitative purpose was conducted by gas chromatography with triple quadrupole mass spectrometer (GC-MS/MS). A matrix-matched calibration curve was performed for quantitative purposes by plotting the area ratio (analyte/I-IS) against concentration using a GC-µECD instrument. According to document No. SANCO/12571/2013, the method was validated by testing the following parameters: linearity, matrix effect, specificity, precision, trueness (bias) and measurement uncertainty. The analytical process was validated analyzing blank honey samples spiked at levels equal to and greater than 0.010 mg/kg (limit of quantification). All parameters were satisfactorily compared with the values established by document No. SANCO/12571/2013. The analytical performance was verified by participating in eight multi-residue proficiency tests organized by BIPEA, obtaining satisfactory z-scores in all 70 determinations. Measurement uncertainty was estimated according to the top-down approaches described in Appendix C of the SANCO document using the within-laboratory reproducibility relative standard deviation combined with laboratory bias using the proficiency test data.

  6. Validation of a method to quantify copper and other metals in olive fruit by ETAAS. Application to the residual metal control after olive tree treatments with different copper formulations.

    Science.gov (United States)

    Soares, Maria Elisa; Pereira, José Alberto; Bastos, Maria Lourdes

    2006-05-31

    An electrothermal atomization atomic absorption spectrometry method was validated to quantify residues of copper, aluminum, cadmium, chromium, iron, lead, and nickel in olive fruit. The linearity ranges under the optimized conditions were 0.19-20.0, 1.11-50.0, 0.02-2.0, 0.15-20.0, 0.80-20.0, 0.35-50.0, and 0.60-50.0 microg/L, respectively. The limits of quantification were, expressed in nanograms per gram of dry weight, 12.6, 74.0, 1.34, 10.0, 53.4, 23.4, and 40.0, respectively. For all of the metals the precision of the instrumental method was 90% for all of the added concentrations. An interference study was also carried out in a simulated matrix, and it was verified that the deviations of the expected values were metals. The method was applied to the monitoring of the residues of the referred metals in olive fruits collected from trees pulverized with three different copper formulations available on the market to control fungal diseases.

  7. Agricultural pesticide residues

    International Nuclear Information System (INIS)

    Fuehr, F.

    1984-01-01

    The utilization of tracer techniques in the study of agricultural pesticide residues is reviewed under the following headings: lysimeter experiments, micro-ecosystems, translocation in soil, degradation of pesticides in soil, biological availability of soil-applied substances, bound residues in the soil, use of macro- and microautography, double and triple labelling, use of tracer labelling in animal experiments. (U.K.)

  8. Characteristics and metal leachability of incinerated sewage sludge ash and air pollution control residues from Hong Kong evaluated by different methods.

    Science.gov (United States)

    Li, Jiang-Shan; Xue, Qiang; Fang, Le; Poon, Chi Sun

    2017-06-01

    The improper disposal of incinerated sewage sludge ash (ISSA) and air pollution control residues (APCR) from sewage sludge incinerators has become an environmental concern. The physicochemical, morphological and mineralogical characteristics of ISSA and APCR from Hong Kong, and the leachability and risk of heavy metals, are presented in this paper. The results showed that a low hydraulic and pozzolanic potential was associated with the ISSA and APCR due to the presence of low contents of SiO 2 , Al 2 O 3 and CaO and high contents of P, S and Cl (especially for APCR). Although high concentrations of Zn and Cu (especially for ISSA) followed by Ni, Pb and As, Se were detected, a low leaching rate of these metals (especially at neutral and alkaline pH) rendered them classifiable as non-hazardous according to the U.S. EPA and Chinese national regulatory limits. The leached metals concentrations from ISSA and APCR were mainly pH dependent, and metals solubilization occurred mainly at low pH. Different leaching tests should be adopted based on the simulated different environmental conditions and exposure scenarios for assessing the leachability as contrasting results could be obtained due to the differences in complexing abilities and final pH of the leaching solutions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Fracture Mechanics Approach to X-Ray Diffraction Method for Spot Welded Lap Joint Structure of Rolled Steel Considered Residual Stress

    International Nuclear Information System (INIS)

    Baek, Seung Yeb; Bae, Dong Ho

    2011-01-01

    Cold and hot-rolled carbon steel sheets are commonly used in railroad cars or commercial vehicles such as the automobile. The sheets used in these applications are mainly fabricated by spot welding, which is a type of electric resistance welding. However, the fatigue strength of a spot-welded joint is lower than that of the base metal because of high stress concentration at the nugget edge of the spot-welded part. In particular, the fatigue strength of the joint is influenced by not only geometrical and mechanical factors but also the welding conditions for the spot-welded joint. Therefore, there is a need for establishing a reasonable criterion for a long-life design for spot-welded structures. In this thesis, ΔP-N f relation curves have been used to determine a long-life fatigue-design criterion for thin-sheet structures. However, as these curves vary under the influence of welding conditions, mechanical conditions, geometrical factors, etc. It is very difficult to systematically determine a fatigue-design criterion on the basis of these curves. Therefore, in order to eliminate such problems, the welding residual stresses generated during welding and the stress distributions around the weld generated by external forces were numerically and experimentally analyzed on the basis of the results, reassessed fatigue strength of gas welded joints

  10. Development of multi-residue method for the determination of pesticides in cereal matrices by isotopic dilution associated to liquid chromatography coupled to tandem mass spectrometry after pressurized liquid extraction

    International Nuclear Information System (INIS)

    El Mrabet, Khadija

    2008-01-01

    Pesticides are nowadays considered as toxic for human health. The maximal residues levels authorized in water and foodstuff are more and more strict. Therefore, selective analytical techniques are necessary for their identification and their quantification. The aim of this thesis was to develop a multi-residue method for the determination of pesticides by isotopic dilution associated to liquid chromatography (LC) coupled with tandem mass spectrometry (MS 2 ) after pressurized liquid extraction. In a first step, an analysis method of phenyl-ureas and triazines in groundwater by isotopic dilution associated to LC/MS 2 after solid phase extraction has been developed. The method has been validated and evaluated by participating to an inter-laboratory study. Concerning cereals, an extraction method of pesticides associated to an analysis by LC/MS 2 has been developed for thirty-eight pesticides representative of twenty-six chemicals families and fourteen labeled compounds in wheat. The analysis has been carried out in reversed phase chromatography. Separation and detection conditions have been optimized. A global analytical protocol consisting of a pressurized liquid extraction step using acetonitrile at 100 deg. C and at 100 bars and followed by purification step of the resulting extract on a polymeric sorbent was developed. The developed method enables to extract thirty-eight pesticides and fourteen labeled compounds from wheat with recovery yield about 85% (RSD =4%, n=3). Moreover, the results show that the application of isotopic dilution can be complex. Although some improvements need to be added regarding experimentation of aged matrices or contaminated samples, the potential of the method has been demonstrated. (author) [fr

  11. FINITE ELEMENT MODEL FOR PREDICTING RESIDUAL ...

    African Journals Online (AJOL)

    direction (σx) had a maximum value of 375MPa (tensile) and minimum value of ... These results shows that the residual stresses obtained by prediction from the finite element method are in fair agreement with the experimental results.

  12. Assessing the Availability of Wood Residues and Residue Markets in Virginia

    OpenAIRE

    Alderman, Delton R. Jr.

    1998-01-01

    A statewide mail survey of primary and secondary wood product manufacturers was undertaken to quantify the production and consumption of wood residues in Virginia. Two hundred and sixty-six wood product manufacturers responded to the study and they provided information on the production, consumption, markets, income or disposal costs, and disposal methods of wood residues. Hardwood and pine sawmills produce approximately 66 percent of Virginia's wood residues. Virginia's wood product man...

  13. Stability assessment on a library scale: a rapid method for the evaluation of the commutability and insertion of residues in C-terminal loops of the CH3 domains of IgG1-Fc.

    Science.gov (United States)

    Hasenhindl, Christoph; Traxlmayr, Michael W; Wozniak-Knopp, Gordana; Jones, Phil C; Stadlmayr, Gerhard; Rüker, Florian; Obinger, Christian

    2013-10-01

    Antigen-binding Fc fragments (Fcab) are generated by engineering the C-terminal loop regions in the CH3 domain of human immunoglobulin G class 1-crystallizable fragment (IgG1-Fc). For an optimum library design with high percentage of well-folded clones for efficient binder selection, information about the correlation between primary structure and stability is needed. Here, we present a rapid method that allows determination of the overall stability of whole libraries of IgG1-Fc on the surface of yeast by flow cytometry. Libraries of IgG1-Fc mutants with distinct regions in AB-, CD- and EF-loops of the CH3 domains randomized or carrying therein insertions of five additional residues were constructed, incubated at increasing temperatures and probed for residual binding of generic Fc ligands. Calculated temperatures of half-maximal irreversible denaturation of the libraries gave a clear hierarchy of tolerance to randomization of distinct loop positions. Experimental data were evaluated by a computational approach and are discussed with respect to the structure of IgG1-Fc and variation in sequence and length of these loops in homologous Fc proteins. Generally, the described method allows for quick assessment of the effects of randomization of distinct regions on the foldability and stability of a yeast-displayed protein library.

  14. Development and validation of a solid-phase extraction method coupled to liquid chromatography with fluorescence detection for the determination of fluoroquinolone residues in powdered infant formulae. Application to the analysis of samples from the Spanish and Latin American market.

    Science.gov (United States)

    Rodriguez, E; Moreno-Bondi, M C; Marazuela, M D

    2008-10-31

    This paper describes a new method for the effective extraction, clean-up and chromatographic analysis of residues of four fluoroquinolones (ciprofloxacin, enrofloxacin, danofloxacin and sarafloxacin) in powdered infant formulae and follow-on preparations. Samples were reconstituted following the manufacturer's recommendations and treated with trichloroacetic acid in methanol 10% (w/v) for deproteinization. Two solid-phase extraction cartridges have been evaluated for sample clean-up and preconcentration, Strata Screen A and Strata X and the later provided the best recoveries for all the analytes tested. Chromatographic analysis has been carried out using a polar endcapped column (AQUA C(18)) and fluorescence detection, with lomefloxacin (LOME) as internal standard. Method validation has been performed according to European Commission Decision 2002/657/EC criteria, in terms of linearity, recovery, precision, specificity, decision limit (CC(alpha)) and detection capability (CC(beta)). Typical recoveries ranged between 70 and 110% at levels below and above the maximum residue limits of the target analytes in bovine milk, with an excellent intralab reproducibility (RSDsmarket, using LC-MS/MS as confirmatory technique.

  15. Development and validation of a multi-residue method for pesticide determination in honey using on-column liquid-liquid extraction and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Pirard, C; Widart, J; Nguyen, B K; Deleuze, C; Heudt, L; Haubruge, E; De Pauw, E; Focant, J-F

    2007-06-08

    We report on the development and validation under ISO 17025 criteria of a multi-residue confirmatory method to identify and quantify 17 widely chemically different pesticides (insecticides: Carbofuran, Methiocarb, Pirimicarb, Dimethoate, Fipronil, Imidacloprid; herbicides: Amidosulfuron, Rimsulfuron, Atrazine, Simazine, Chloroturon, Linuron, Isoxaflutole, Metosulam; fungicides: Diethofencarb) and 2 metabolites (Methiocarb sulfoxide and 2-Hydroxytertbutylazine) in honey. This method is based on an on-column liquid-liquid extraction (OCLLE) using diatomaceous earth as inert solid support and liquid chromatography (LC) coupled to mass spectrometry (MS) operating in tandem mode (MS/MS). Method specificity is ensured by checking retention time and theoretical ratio between two transitions from a single precursor ion. Linearity is demonstrated all along the range of concentration that was investigated, from 0.1 to 20 ng g(-1) raw honey, with correlation coefficients ranging from 0.921 to 0.999, depending on chemicals. Recovery rates obtained on home-made quality control samples are between 71 and 90%, well above the range defined by the EC/657/2002 document, but in the range we had fixed to ensure proper quantification, as levels found in real samples could not be corrected for recovery rates. Reproducibility is found to be between 8 and 27%. Calculated CCalpha and CCbeta (0.0002-0.943 ng g(-1) for CCalpha, and 0.0002-1.232 ng g(-1) for CCbeta) show the good sensitivity attained by this multi-residue analytical method. The robustness of the method has been tested in analyzing more than 100 raw honey samples collected from different areas in Belgium, as well as some wax and bee samples, with a slightly adapted procedure.

  16. Residual stresses of water-jet peened austenitic stainless steel

    International Nuclear Information System (INIS)

    Suzuki, Kenji; Shobu, Takahisa; Shiro, Ayumi

    2013-01-01

    The specimen material was austenitic stainless steel, SUS316L. The residual stress was induced by water-jet peening. The residual stress was measured using the 311 diffraction with conventional X-rays. The measured residual stress showed the equi-biaxial stress state. To investigate thermal stability of the residual stress, the specimen was aged thermally at 773K in air to 1000h. The residual stress kept the equi-biaxial stress state against the thermal aging. Lattice plane dependency of the residual stress induced by water-jet peening was evaluated using hard synchrotron X-rays. The residual stress measured by the soft lattice plane showed the equi-biaxial stress state, but the residual stress measured by the hard lattice plane did not. In addition, the distributions of the residual stress in the depth direction were measured using a strain scanning method with hard synchrotron X-rays and neutrons. (author)

  17. Handling of Solid Residues

    International Nuclear Information System (INIS)

    Medina Bermudez, Clara Ines

    1999-01-01

    The topic of solid residues is specifically of great interest and concern for the authorities, institutions and community that identify in them a true threat against the human health and the atmosphere in the related with the aesthetic deterioration of the urban centers and of the natural landscape; in the proliferation of vectorial transmitters of illnesses and the effect on the biodiversity. Inside the wide spectrum of topics that they keep relationship with the environmental protection, the inadequate handling of solid residues and residues dangerous squatter an important line in the definition of political and practical environmentally sustainable. The industrial development and the population's growth have originated a continuous increase in the production of solid residues; of equal it forms, their composition day after day is more heterogeneous. The base for the good handling includes the appropriate intervention of the different stages of an integral administration of residues, which include the separation in the source, the gathering, the handling, the use, treatment, final disposition and the institutional organization of the administration. The topic of the dangerous residues generates more expectation. These residues understand from those of pathogen type that are generated in the establishments of health that of hospital attention, until those of combustible, inflammable type, explosive, radio-active, volatile, corrosive, reagent or toxic, associated to numerous industrial processes, common in our countries in development

  18. Development and validation of a standardized method for the determination of morpholine residues in fruit commodities by liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Hengel, Matt J; Jordan, Rick; Maguire, Wesley

    2014-04-30

    An analytical method was developed for the determination of morpholine on apples and citrus. The method utilized acidified methanol extraction, centrifugation, and determination by hydrophilic interaction liquid chromatography with electrospray ionization and tandem mass spectrometry (HILIC-ESI-MS/MS). Validation of the method occurred at the Pacific Agricultural Laboratory (PAL, Portland, OR, USA) and the Trace Analytical Laboratory (TAL, UC Davis, CA, USA). Method validation recoveries from control apple, orange, lemon, and grapefruit samples ranged from 84 to 120% over three levels of fortification (0.01, 0.04, and 0.2 μg/g). The limit of quantitation (LOQ) for all commodities was 0.01 μg/g, and the calculated method detection limit (MDL) ranged from 0.0010 to 0.0040 μg/g.

  19. A Two-Stage Method for Structural Damage Prognosis in Shear Frames Based on Story Displacement Index and Modal Residual Force

    Directory of Open Access Journals (Sweden)

    Asghar Rasouli

    2015-01-01

    Full Text Available A two-stage method is proposed to properly identify the location and the extent of damage in shear frames. In the first stage, a story displacement index (SDI is presented to precisely locate the damage in the shear frame which is calculated using the modal analysis information of the damaged structure. In the second stage, by defining a new objective function, the extent of the actual damage is determined via an imperialist competitive algorithm. The performance of the proposed method is demonstrated by implementing the technique to three examples containing five-, ten-, and twenty-five-story shear frames with noises and without them in modal data. Moreover, the performance of the proposed method has been verified through using a benchmark problem. Numerical results show the high efficiency of the proposed method for accurately identifying the location and the extent of structural damage in shear frames.

  20. Biodegradation of some agricultural residues by fungi in agitated ...

    African Journals Online (AJOL)

    Digestibility of agricultural residues in animal feeding is deeply dependent on the amounts and types of their fibers. Biological treatment of agricultural residues is a new method for improvement of digestibility. Therefore, the capacity of a few fungi in biodegradation of some agricultural residues was studied. Losses of crude ...

  1. Cover crop residue management for optimizing weed control

    NARCIS (Netherlands)

    Kruidhof, H.M.; Bastiaans, L.; Kropff, M.J.

    2009-01-01

    Although residue management seems a key factor in residue-mediated weed suppression, very few studies have systematically compared the influence of different residue management strategies on the establishment of crop and weed species. We evaluated the effect of several methods of pre-treatment and

  2. Residual stresses in steel and zirconium weldments

    International Nuclear Information System (INIS)

    Root, J.H.; Coleman, C.E.; Bowden, J.W.

    1997-01-01

    Three-dimensional scans of residual stress within intact weldments provide insight into the consequences of various welding techniques and stress-relieving procedures. The neutron diffraction method for nondestructive evaluation of residual stresses has been applied to a circumferential weld in a ferritic steel pipe of outer diameter 114 mm and thickness 8.6 mm. The maximum tensile stresses, 250 MPa in the hoop direction, are found at mid-thickness of the fusion zone. The residual stresses approach zero within 20 mm from the weld center. The residual stresses caused by welding zirconium alloy components are partially to blame for failures due to delayed-hydride cracking. Neutron diffraction measurements in a GTA-welded Zr-2.5 Nb plate have shown that heat treatment at 530 C for 1 h reduces the longitudinal residual strain by 60%. Neutron diffraction has also been used to scan the residual stresses near circumferential electron beam welds in irradiated and unirradiated Zr-2.5 Nb pressure tubes. The residual stresses due to electron beam welding appear to be lower than 130 MPa, even in the as-welded state. No significant changes occur in the residual stress pattern of the electron-beam welded tube, during a prolonged exposure to thermal neutrons and the temperatures typical of an operating nuclear reactor

  3. [Residual neuromuscular blockade].

    Science.gov (United States)

    Fuchs-Buder, T; Schmartz, D

    2017-06-01

    Even small degrees of residual neuromuscular blockade, i. e. a train-of-four (TOF) ratio >0.6, may lead to clinically relevant consequences for the patient. Especially upper airway integrity and the ability to swallow may still be markedly impaired. Moreover, increasing evidence suggests that residual neuromuscular blockade may affect postoperative outcome of patients. The incidence of these small degrees of residual blockade is relatively high and may persist for more than 90 min after a single intubating dose of an intermediately acting neuromuscular blocking agent, such as rocuronium and atracurium. Both neuromuscular monitoring and pharmacological reversal are key elements for the prevention of postoperative residual blockade.

  4. TENORM: Wastewater Treatment Residuals

    Science.gov (United States)

    Water and wastes which have been discharged into municipal sewers are treated at wastewater treatment plants. These may contain trace amounts of both man-made and naturally occurring radionuclides which can accumulate in the treatment plant and residuals.

  5. A novel analytical method for the determination of residual moisture in plutonium dioxide: Supercritical fluid extraction/Fourier transform infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, A.M.; Hollis, W.K.; Rubin, J.B.; Taylor, C.M.V.; Jasperson, M.N.; Vance, D.E.; Rodriguez, J.B.

    1999-02-01

    A novel approach has been developed at the Los Alamos National Laboratory for the quantitative determination of moisture content in impure plutonium oxide. The method combines a commercial supercritical fluid extraction instrument using supercritical carbon dioxide (SCCO{sub 2}) with on-line detection using a high-pressure Fourier Transform Infrared Spectroscopy (FTIR) cell. The combined SCCO{sub 2}/FTIR system has been modified for use inside a fully enclosed glove box. A series of validation experiments were performed using a pure, surrogate oxide (ThO{sub 2}) and an inorganic hydrate (CaSO{sub 4}{center_dot}2H{sub 2}O). The level of agreement between LOI and SCCO{sub 2}/FTIR for the surrogate oxide is excellent. The results for the inorganic hydrate showed excellent correlation with the known amount of water present. Results obtained for a group of nominally pure PuO{sub 2} samples were verified by independent measurement. The results of SCCO{sub 2}/FTIR for impure PuO{sub 2} samples is consistently lower than the results of obtained from the current analytical method (Loss On Ignition), indicating that the current method is inadequate for analytical purposes. While further verification experiments of the SCCO{sub 2}/FTIR method are underway, these initial results suggest that SCCO{sub 2}/FTIR could be used as an alternative analytical method for the Materials Identification and Surveillance program.

  6. Residuation in orthomodular lattices

    Directory of Open Access Journals (Sweden)

    Chajda Ivan

    2017-04-01

    Full Text Available We show that every idempotent weakly divisible residuated lattice satisfying the double negation law can be transformed into an orthomodular lattice. The converse holds if adjointness is replaced by conditional adjointness. Moreover, we show that every positive right residuated lattice satisfying the double negation law and two further simple identities can be converted into an orthomodular lattice. In this case, also the converse statement is true and the corresponence is nearly one-to-one.

  7. A survey of residual analysis and a new test of residual trend.

    Science.gov (United States)

    McDowell, J J; Calvin, Olivia L; Klapes, Bryan

    2016-05-01

    A survey of residual analysis in behavior-analytic research reveals that existing methods are problematic in one way or another. A new test for residual trends is proposed that avoids the problematic features of the existing methods. It entails fitting cubic polynomials to sets of residuals and comparing their effect sizes to those that would be expected if the sets of residuals were random. To this end, sampling distributions of effect sizes for fits of a cubic polynomial to random data were obtained by generating sets of random standardized residuals of various sizes, n. A cubic polynomial was then fitted to each set of residuals and its effect size was calculated. This yielded a sampling distribution of effect sizes for each n. To test for a residual trend in experimental data, the median effect size of cubic-polynomial fits to sets of experimental residuals can be compared to the median of the corresponding sampling distribution of effect sizes for random residuals using a sign test. An example from the literature, which entailed comparing mathematical and computational models of continuous choice, is used to illustrate the utility of the test. © 2016 Society for the Experimental Analysis of Behavior.

  8. Characterization and electrochemical performance of lithium-active titanium dioxide inlaid LiNi0.5Co0.2Mn0.3O2 material prepared by lithium residue-assisted method

    International Nuclear Information System (INIS)

    Li, Lingjun; Chen, Zhaoyong; Song, Liubin; Xu, Ming; Zhu, Huali; Gong, Li; Zhang, Kaili

    2015-01-01

    Highlights: • LiTiO 2 -inlaid LiNi 0.5 Co 0.2 Mn 0.3 O 2 is prepared by lithium residue-assisted method. • The unique inlaid architecture inherits the advantages of coating and doping. • LiTiO 2 inlaying enhances the pristine at high cyclability and rate properties. • Excess LiTiO 2 modification results in low Li + diffusion coefficient. • The 3 mol% LiTiO 2 inlaid sample exhibits the best electrochemical performance. - Abstract: The lithium residues are consumed as raw materials to in-situ synthesize the LiTiO 2 -inlaid LiNi 0.5 Co 0.2 Mn 0.3 O 2 composites. The effects of various LiTiO 2 contents on the morphology, structure, and electrochemical properties of LiNi 0.5 Co 0.2 Mn 0.3 O 2 materials are investigated in detail. Energy dispersive spectrometer mapping, high-resolution transmission electron microscopy and fast Fourier transform analysis confirm that the spherical particles of LiNi 0.5 Co 0.2 Mn 0.3 O 2 are completely coated by crystalline LiTiO 2 phase; X-ray diffraction, cross-section SEM and corresponding EDS results indicate that Ti ions are also doped into the bulk LiNi 0.5 Co 0.2 Mn 0.3 O 2 with gradient distribution. Electrochemical tests show that the LiTiO 2 -inlaid samples exhibit excellent reversible capacity, enhanced cyclability, superior lithium diffusion coefficient and rate properties. Specially, the 3 mol% LiTiO 2 inlaid sample maintains 153.7 mA h g −1 with 94.4% capacity retention after 100 cycles between 2.7–4.4 V at 1 C, take 30% advantage than that of the pristine one (118.2 mA h g −1 ). This improvement can be attributed to the removal of lithium residues and suitable LiTiO 2 inlaying. The absence of lithium residue is helpful to retard the decomposition of LiPF 6 . While, suitable LiTiO 2 inlaying can protect the bulk from directly contacting the electrolyte, buffer the volume change of core and shell during cycles, increase the surface electronic conductivity and offer a 3D path for Li + diffusion from the bulk to

  9. Characterization of Hospital Residuals

    International Nuclear Information System (INIS)

    Blanco Meza, A.; Bonilla Jimenez, S.

    1997-01-01

    The main objective of this investigation is the characterization of the solid residuals. A description of the handling of the liquid and gassy waste generated in hospitals is also given, identifying the source where they originate. To achieve the proposed objective the work was divided in three stages: The first one was the planning and the coordination with each hospital center, in this way, to determine the schedule of gathering of the waste can be possible. In the second stage a fieldwork was made; it consisted in gathering the quantitative and qualitative information of the general state of the handling of residuals. In the third and last stage, the information previously obtained was organized to express the results as the production rate per day by bed, generation of solid residuals for sampled services, type of solid residuals and density of the same ones. With the obtained results, approaches are settled down to either determine design parameters for final disposition whether for incineration, trituration, sanitary filler or recycling of some materials, and storage politics of the solid residuals that allow to determine the gathering frequency. The study concludes that it is necessary to improve the conditions of the residuals handling in some aspects, to provide the cleaning personnel of the equipment for gathering disposition and of security, minimum to carry out this work efficiently, and to maintain a control of all the dangerous waste, like sharp or polluted materials. In this way, an appreciable reduction is guaranteed in the impact on the atmosphere. (Author) [es

  10. Validation of an ultra-high-performance liquid chromatography-tandem mass spectrometry method to quantify illicit drug and pharmaceutical residues in wastewater using accuracy profile approach.

    Science.gov (United States)

    Hubert, Cécile; Roosen, Martin; Levi, Yves; Karolak, Sara

    2017-06-02

    The analysis of biomarkers in wastewater has become a common approach to assess community behavior. This method is an interesting way to estimate illicit drug consumption in a given population: by using a back calculation method, it is therefore possible to quantify the amount of a specific drug used in a community and to assess the consumption variation at different times and locations. Such a method needs reliable analytical data since the determination of a concentration in the ngL -1 range in a complex matrix is difficult and not easily reproducible. The best analytical method is liquid chromatography - mass spectrometry coupling after solid-phase extraction or on-line pre-concentration. Quality criteria are not specially defined for this kind of determination. In this context, it was decided to develop an UHPLC-MS/MS method to analyze 10 illicit drugs and pharmaceuticals in wastewater treatment plant influent or effluent using a pre-concentration on-line system. A validation process was then carried out using the accuracy profile concept as an innovative tool to estimate the probability of getting prospective results within specified acceptance limits. Influent and effluent samples were spiked with known amounts of the 10 compounds and analyzed three times a day for three days in order to estimate intra-day and inter-day variations. The matrix effect was estimated for each compound. The developed method can provide at least 80% of results within ±25% limits except for compounds that are degraded in influent. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Development and validation of a multi-residue method for the detection of a wide range of hormonal anabolic compounds in hair using gas chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Rambaud, Lauriane [LABERCA, Ecole Nationale Veterinaire de Nantes, Route de Gachet, BP50707, 44307 Nantes Cedex 3 (France); Monteau, Fabrice [LABERCA, Ecole Nationale Veterinaire de Nantes, Route de Gachet, BP50707, 44307 Nantes Cedex 3 (France); Deceuninck, Yoann [LABERCA, Ecole Nationale Veterinaire de Nantes, Route de Gachet, BP50707, 44307 Nantes Cedex 3 (France); Bichon, Emmanuelle [LABERCA, Ecole Nationale Veterinaire de Nantes, Route de Gachet, BP50707, 44307 Nantes Cedex 3 (France); Andre, Francois [LABERCA, Ecole Nationale Veterinaire de Nantes, Route de Gachet, BP50707, 44307 Nantes Cedex 3 (France); Le Bizec, Bruno [LABERCA, Ecole Nationale Veterinaire de Nantes, Route de Gachet, BP50707, 44307 Nantes Cedex 3 (France)]. E-mail: lebizec@vet-nantes.fr

    2007-03-14

    The monitoring of anabolic steroid residues in hair is undoubtedly one of the most efficient strategies to demonstrate the long-term administration of these molecules in meat production animals. A multi-residue sample preparation procedure was developed and validated for 28 steroids. A 100 mg hair sample was grinded into powder and extracted at 50 deg. C with methanol. After acidic hydrolysis and extraction with ethyl acetate, phenolsteroids, such as estrogens, resorcyclic acid lactones and stilbens in one hand, are separated from androgens and progestagens in the other hand. Solid phase extractions were performed before applying a specific derivatisation for each compound sub-group. Detection and identification were achieved using gas chromatography-tandem mass spectrometry with acquisition in the selected reaction monitoring mode after electron ionisation. The method was validated according to the 2002/657/EC guideline. Decision limits (CC{alpha}) for main steroids were in the 0.1-10 {mu}g kg{sup -1} range.

  12. A Confirmatory Method Based on HPLC-MS/MS for the Detection and Quantification of Residue of Tetracyclines in Nonmedicated Feed.

    Science.gov (United States)

    Gavilán, Rosa E; Nebot, Carolina; Veiga-Gómez, Maria; Roca-Saavedra, Paula; Vazquez Belda, Beatriz; Franco, Carlos M; Cepeda, Alberto

    2016-01-01

    The Commission Regulation 574/2011/EC set up maximum levels of coccidiostats and histomonostats in nonmedicated feed as a consequence of carry-over during manufacturing. Carry-over takes place from medicated to nonmedicated feed during feed production. Similar contamination could also occur for other pharmaceuticals such as tetracyclines, a group of antibiotics commonly employed in food production animal. The objective of this work is to present a simple and fast method for the simultaneous detection of four tetracyclines (chlortetracycline, doxycycline, oxytetracycline, and tetracycline) in nontarget feed at a μg/kg level. Validation of the method was performed according to the guideline included in the Commission Decision 2002/657/EC for official method. The validated method was successfully applied to 50 feed samples collected from different milk farms and 25 samples obtained from feed manufacturers. While oxytetracycline was the tetracycline most frequently detected, chlortetracycline was the analyte measured at the highest concentration 15.14 mg/Kg. From 75 nonmedicated feed analysed 15% resulted to be positive for the presence of one tetracycline.

  13. A Mixed Methods Study to Determine if High School Athletics Participation Carries Any Residual Positive Effects for Nontraditional Student Success in a College in Central Florida

    Science.gov (United States)

    Mueller, Kasey Lloyd

    2017-01-01

    Nontraditional students returning to college have many outside stressors that potentially prohibit academic success including full-time jobs, home life (children, spouses, and bills), and lack of time or understanding of college assignments. An explanatory mixed methods study was conducted for the purpose of determining if and for how long the…

  14. Development of an UPLC-MS/MS Sulfonamide Multi-residue Method and It's Application to Water, Manure Slurry, and Soils from Swine Rearing Facilities

    Science.gov (United States)

    An analytical method was developed using ultra performance liquid chromatography-triple quadrupole-tandem mass spectrophotometry (UPLC-TQ-MS/MS) to simultaneously analyze 14 sulfonamides (SA) in six minutes. The instrumental detection limit based on signal-to-noise ratio (S/N) > 3, was below 1 pg/µL...

  15. Inexpensive, effective novel activated carbon fibers for sample cleanup: application to multipesticide residue analysis in food commodities using a QuEChERS method.

    Science.gov (United States)

    Singh, Shiv; Srivastava, Anshuman; Singh, Sheelendra Pratap

    2018-03-01

    Phenolic resin based activated carbon fibers (ACFs) were applied for the first time as a reversed-dispersive solid-phase extraction (r-DSPE) sorbent. A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was applied to determine 26 pesticides (organophosphates, organochlorines, synthetic pyrethroids, and herbicides) in different complex matrices, including cauliflower, cucumber, banana, apple, wheat, and black gram. Different physicochemical characterization techniques were used to investigate the engineering and structural properties of the r-DSPE sorbent. All the chromatographic analyses were performed with a gas chromatograph equipped with an electron capture detector. The recoveries of all 26 pesticides were acceptable (70-120%), with relative standard deviations of less than 15%. The limit of detection and the limit of quantification were 1.13-5.48 ng/g and 3.42-16.60 ng/g, respectively. In the original QuEChERS method, primary secondary amine is extensively used as the r-DSPE sorbent in the cleanup process, but it is eightfold more expensive than the ACFs used in this study. Therefore, the modified QuEChERS method using ACFs during the cleanup process is more efficient, cheaper, and more robust to determine pesticides from different types of matrices, including vegetables, grains, and fruits, and ACFs could be used as a cost-effective alternative to primary secondary amine. Graphical Abstract Sample clean-up using PSA and ACF as r-DSPE sorbent in QuEChERS method.

  16. Residue analysis of four diacylhydrazine insecticides in fruits and vegetables by Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method using ultra-performance liquid chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Liu, Xingang; Xu, Jun; Dong, Fengshou; Li, Yuanbo; Song, Wenchen; Zheng, Yongquan

    2011-08-01

    The new analytical method using Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) procedure for simultaneous determination of diacylhydrazine insecticide residues in fruits and vegetables was developed using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The four insecticides (tebufenozide, methoxfenozide, chromafenozide, and halofenozide) were extracted from six fruit and vegetable matrices using acetonitrile and subsequently cleaned up using primary secondary amine (PSA) or octadecylsilane (C18) as sorbent prior to UPLC-MS/MS analysis. The determination of the target compounds was achieved in less than 3.0 min using an electrospray ionization source in positive mode (ESI+) for tebufenozide, methoxfenozide, and halofenozide and in negative mode (ESI-) for chromafenozide. The limits of detection were below 0.6 μg kg(-1), while the limit of quantification did not exceed 2 μg kg(-1) in different matrices. The QuEChERS procedure by using two sorbents (PSA and C18) and the matrix-matched standards gave satisfactory recoveries and relative standard deviation (RSD) values in different matrices at four spiked levels (0.01, 0.05, 0.1, and 1 mg kg(-1)). The overall average recoveries for this method in apple, grape, cucumber, tomato, cabbage, and spinach at four levels ranged from 74.2% to 112.5% with RSDs in the range of 1.4-13.8% (n = 5) for all analytes. This study provides a theoretical basis for China to draw up maximum residue limits and analytical method for diacylhydrazine insecticide in vegetables and fruits.

  17. Development of a multi-residue method for the determination of pesticides in cereals and dry animal feed using gas chromatography-tandem quadrupole mass spectrometry II. Improvement and extension to new analytes.

    Science.gov (United States)

    Walorczyk, Stanisław

    2008-10-24

    This paper describes the extension and re-validation of a previously published multi-residue method to currently 140 pesticides and 4 pesticide degradation products in cereals and feedingstuffs. The pesticides were extracted using buffered QuEChERS ("quick, easy, cheap, rugged, effective and safe") method and then cleaned up using dispersive solid-phase extraction with Bondesil PSA and C18 sorbents, and optionally by a freezing-out clean-up step. The final extracts were analyzed in a single injection gas chromatographic-tandem quadrupole mass spectrometric (GC-MS/MS) acquisition method. A high degree of confidence was achieved by entering two multiple reaction monitoring transitions per compound. In this way, quantification of analytical results and unequivocal identification of pesticide residues in compliance with the recent European Union criteria could be done in a single analysis. Thorough optimization of the GC-MS/MS acquisition conditions and application of an effective clean-up procedure has resulted in a remarkable enhancement of the validation parameters. The linearity of the calibration curves was excellent in matrix-matched standards, and yielded the coefficients of determination (R(2))> or =0.99 for approximately 96% of the target analytes. Average recoveries of the pesticides spiked at 0.01mgkg(-1) into a feed mixture and wheat grain were in the range 70-120% with associated RSD values feed mixtures and other samples such as malt, starch and dry vegetables have been analyzed. A total of 15 different pesticides have been detected, among which pirimiphos methyl (19 cases), deltamethrin (14 cases), tolylfluanid (5 cases), dichlofluanid (5 cases), and tebuconazole (4 cases) were the most frequently encountered ones.

  18. A simple multi-residue method for the determination of pesticides in fruits and vegetables using a methanolic extraction and ultra-high-performance liquid chromatography-tandem mass spectrometry: optimization and extension of scope.

    Science.gov (United States)

    Hanot, V; Goscinny, S; Deridder, M

    2015-03-06

    In 2004, a new multi-residue pesticides method had been published using methanol as extraction solvent. Our goal for this study was to optimize the analytical scheme while extending the compound scope from 19 to 200 pesticides. The main changes from the original method take place at the sample extraction and processing with a special attention to make the overall method fit for routine analysis with minimal cost. Hence, after a quick Ultra-Turrax homogenization with a methanolic solution, the sample is simply diluted before the separation and detection by ultra-high-performance liquid chromatography and MS/MS detection for quantitative and confirmatory purposes. The performance of the method including limits of quantification (LOQs), linearity, matrix effect, precision was evaluated during validation in accordance with the European Union SANCO/12571/2013 regulatory guidelines. Two representative matrices, lettuce and orange, were selected and fortified at two concentration levels for these experiments. At the LOQ and ten times the LOQ, recoveries of the analytes were mostly within 70-120%, with coefficients of variation lower than 25% in intra-day repeatability conditions. In addition to being simple and fast, these results demonstrate the suitability of the optimized method for the analysis of large scope pesticides in routine laboratories. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Critical comparison of two independent measurements of residual stress in an electron-beam welded uranium cylinder: Neutron diffraction and the contour method

    Energy Technology Data Exchange (ETDEWEB)

    Brown, D.W., E-mail: dbrown@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Holden, T.M. [Northern Stress Technologies, Deep River, Ontario, K0J 1P0 (Canada); Clausen, B.; Prime, M.B.; Sisneros, T.A.; Swenson, H. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Vaja, J. [Atomic Weapons Establishment, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom)

    2011-02-15

    Neutron diffraction and contour method measurements were conducted to assess the stresses associated with an electron-beam, circumferential, partial penetration weld of a uranium tube. To obtain reasonable results in the coarse-grained base metal, the specimen was continuously rotated during the neutron experiments to average over the entire circumference. The severe anisotropic character of uranium, which has an orthorhombic crystal structure, forces a number of judicious choices to be made in the neutron analysis. For the contour method, the cylindrical geometry necessitated the development of a two-step process, and discontinuities across the unwelded portion of the joint required special treatment. High tensile hoop stresses ({approx}300 MPa) were found in the center of the weld close to the outside diameter. Balancing hoop compression was observed in the far-field stress profile. Also, a tensile axial stress (85 {+-} 25 MPa) was observed near the outer diameter.

  20. A Confirmatory Method Based on HPLC-MS/MS for the Detection and Quantification of Residue of Tetracyclines in Nonmedicated Feed

    OpenAIRE

    Gavil?n, Rosa E.; Nebot, Carolina; Veiga-G?mez, Maria; Roca-Saavedra, Paula; Vazquez Belda, Beatriz; Franco, Carlos M.; Cepeda, Alberto

    2016-01-01

    The Commission Regulation 574/2011/EC set up maximum levels of coccidiostats and histomonostats in nonmedicated feed as a consequence of carry-over during manufacturing. Carry-over takes place from medicated to nonmedicated feed during feed production. Similar contamination could also occur for other pharmaceuticals such as tetracyclines, a group of antibiotics commonly employed in food production animal. The objective of this work is to present a simple and fast method for the si...