bluuebunny/crossref_metadata_2025 huggingface dataset:
Generalized numerical integration of moments
Authors: Griffiths D. V.
Published: November 2005

Sampling points and weighting coefficients of the Gaussian type are presented for integrands typically encountered in axisymmetric finite elements. The proposed method is a generalization of Gaussian Integration of Moments for non‐zero limits of integration. The method achieves one extra order of accuracy in the integration of polynomials as compared with the Gauss‐Legendre method with the same number of sampling points. Although the locations of sampling points require the solution of non‐linear equations, analytical solutions are presented for the cases of one and two sampling points. Special cases of these general expressions are shown to include both Gauss‐Legendre integration corresponding to an integration range at a considerable distance from the axis of symmetry, and Fishman integration corresponding to an integration range whose lower limit lies on the axis of symmetry.
An indirect BIM for static analysis of spherical shells using auxiliary boundaries
Authors: Simos Nikolaos , Sadegh Ali M.
Published: November 2005

Boundary integral approaches, which are known for their mathematical sophistication and elegance as well as their ability to reduce the problem dimensions by one, suffer from drawbacks associated with their performance in the vicinity of the boundaries. Such behaviour is the result of the unavoidable, in most cases, discretization of the boundary on one hand, which consequently results in the reduction of the integral problem to an algebraic one, and of the tedious evaluation of singularities that are present in most kernels on the other. The sensitivity of solutions of shell problems using a special form of boundary integral method is studied. Such an approach hopes to achieve a better representation of the solution near the boundaries by utilizing fictitious surface lines to perform the kernel integrations. Lastly, the performance of the integral formulation is examined through some representative examples.
A new uniformly valid asymptotic integration algorithm for elasto‐plastic creep and unified viscoplastic theories including continuum damage
Authors: Chulya Abhisak , Walker Kevin P.
Published: November 2005

A new scheme to integrate a system of stiff differential equations for both the elasto‐plastic‐creep and the unified viscoplastic theories is presented. The method has high stability, allows large time increments, and is implicit and iterative. It is suitable for use with continuum damage theories. The scheme was incorporated into MARC, a commercial finite element code, through a user subroutine called HYPELA. Results from numerical problems under complex loading histories are presented for both small and large scale analysis. To demonstrate the scheme's accuracy and efficiency, comparisons to a self‐adaptive forward Euler method are made.
A physical interpretation of conventional finite element formulations of conduction‐type problems
Authors: Comini G. , Giudice S. Del
Published: November 2005

An essentially physical approach is utilized to derive a finite element formulation of conduction‐type problems. The same systems of algebraic equations, which are usually yielded by Galerkin or variational methods, are obtained here on the basis of energy balances which lead to conservative numerical models, both at element and at node levels. As a result, it is shown that, in conventional implementations of the finite element method for conduction‐type problems, there is no artificial creation or destruction of a conserved variable. Therefore, for such formulations, inaccuracies that arise with finite sizes of elements do not depend on non‐conservation but are due solely to approximation erros. In the paper, a clear physical interpretation is also given for all the matrices and vectors which are commonly defined in most finite element formulations of conduction‐type problems.
Boundary elements with equilibrium satisfaction—A consistent formulation for potential and elastostatic problems
Authors: Telles J. C. F. , de Paula F. A.
Published: November 2005

A direct boundary element formulation which produces equilibrium satisfaction in the numerical solutions is presented. It consistently originates from the standard boundary integral equation with a simple modification in the fundamental solution and can be applied to general potential and elasticity problems. Since boundary equilibrium is guaranteed for any problem discretization, the procedure is also found useful to generate improved stiffness matrices, which permits combination with finite elements.

Some elastostatic examples are included to demonstrate the applicability of the formulation.
Adaptive finite element methods for hyperbolic systems with application to transient acoustics
Authors: Safjan A. , Demkowicz L. , Oden J. T.
Published: November 2005

The solution of the hyperbolic systems of equations governing transient acoustics by adaptive finite elements and various finite difference time discretization schemes is addressed. Emphasis is placed on the use of a class of implicit Runge‐Kutta methods for temporal approximations.
Multiple scale finite element methods
Authors: Liu Wing Kam , Zhang Yan , Ramirez Martin R.
Published: November 2005

New temporal and spatial discretization methods are developed for multiple scale structural dynamic problems. The concept of fast and slow time scales is introduced for the temporal discretization. The required time step is shown to be dependent only on the slow time scale, and therefore, large time steps can be used for high frequency problems. To satisfy the spatial counterpart of the requirement on time step constraint, finite‐spectral elements and finite wave elements are developed. Finite‐spectral element methods combine the usual finite elements with the fast convergent spectral functions to obtain a faster convergence rate; whereas, finite wave elements are developed in parallel to the temporal shifting technique. Therefore, the spatial resolution is increased substantially. These methods are especially applicable to structural acoustics and linear space structures. Numerical examples are presented to illustrate the effectiveness of these methods.
Stress analysis of flat plates with shear using explicit stiffness matrix
Authors: Sengupta Dipak
Published: November 2005

An explicit expression for the stiffness matrix is worked out for a triangular plate bending element considering the effect of transverse shear deformation. The element has twelve nodes on the sides and four nodes internal to it. The formulation is displacement type and the use of area co‐ordinates makes it possible to obtain the shape functions explicitly. Separate polynomials are assumed for transverse displacement and rotations. To obtain the element stiffness matrix no matrix inversion or numerical integration need be carried out and only a few matrix multiplications of low order are necessary. The element, which is initially of thirty five degrees of freedom, can be reduced to a thirty degrees of freedom one by condensation of the internal nodes. An interesting feature of the element developed is that the values of nodal moments computed at a node point, considering different elements surrounding the node, do not vary significantly. Thus the nodal moments can be obtained directly at node points. Also, the element does not give rise to any inconvenience like locking, even for very thin plates. The straightforward approach in formation of the element stiffness will cut down the storage space considerably and will also call for less CPU time, thus making the use of the element well suited to low capacity computers. A number of plate bending problems have been worked out using the present element for different thickness to side ratios and a comparison has been made with the available results. Good accuracy has been observed in all cases, even for a small number of elements.
Improvement of quadratic finite element for Mindlin plate bending
Authors: Kim Sun‐Hoon , Choi Chang‐Koon
Published: November 2005

The present paper is concerned with the improvement of a finite element for the analysis of plate bending structures. The element formulation is based upon the Mindlin plate concept. The displacement field of this element is formed by adding non‐conforming modes to two rotational displacement components of an 8‐node plate element. The element has the requisite numbers of zero eigenvalues associated with rigid body modes to avoid the spurious zero energy mode. It is shown that the results obtained by the element converged to the exact solutions very rapidly as the mesh is refined and exhibited reliable solutions through numerical studies for standard benchmark problems. This element is shown to overcome the shear locking problem completely in a very thin plate situation, even for irregular meshes.
Unified computational model for static and dynamic frictional contact analysis
Authors: Ibrahimbegovic Adnan , Wilson Edward L.
Published: November 2005

A new computational model for the analysis of friction phenomena is presented in this work. The model is a regularized form of the Coulomb friction law, which stems from the analogy of friction and plasticity phenomena. The basic difference from the classical plasticity is the non‐linear form of both the normal and the tangential elastic compliance. The numerical implementation of the model is also discussed. The methodology presented herein is used for the analysis of both dynamic and quasi‐static problems. The dynamic substructuring and the static condensation are used to enhance the computational efficiency.
Efficient formulation of robust hybrid elements using orthogonal stress/strain interpolants and admissible matrix formulation
Authors: Sze K. Y.
Published: November 2005

This paper presents an investigation of using orthogonal constant and higher order stress modes in formulating efficient hybrid elements by equipping the primary idea of Bergan and Hanssen. Two sample elements modified from Pian‐Sumihara 5‐β plane and Pian‐Tong 18‐β hexahedral assumed contravariant stress elements are derived. With the suggested admissible simplifications of the flexibility matrices incorporated into the two new elements, new plane and hexahédral elements requiring respectively no and a negligible amount of computing efforts for inverting the flexibility matrices are formed. All, proposed elements are stable, invariant, contain no empirically determined factor and strictly pass the patch test. Popular benchmark problems are studied and the accuracy of the proposed elements is close to their parent models.
Elastostatic analysis of infinite solids using finite elements
Authors: Sharan Shailendra K.
Published: November 2005

A novel technique is developed to simulate the effects of an infinite elastic solid by using multiple springs having spatially varying stiffnesses. The spring constants are computed by numerical integration of classical solutions for point or line loads in an infinite or semi‐infinite elastic mass. Under certain conditions, even the 'exact' values of spring constants may become negative at some nodes. A simple and highly effective algorithm is proposed to remove this computational difficulty. The technique is applied to the computation of displacements and stresses around underground openings. For a circular opening subjected to different stress conditions, spring constants computed by the proposed numerical integration technique are found to be 'identical' to their 'exact' values. Results obtained by the proposed technique for displacements and stresses around circular and non‐circular openings are found to be in an excellent agreement with classical and boundary element solutions. The principal advantages of the proposed technique are that an unbounded solid may be simulated by a relatively very small finite model and a standard finite element code requires no modification for its implementation.
Effect of warping‐pretwist coupling on the natural vibration of torsionally clamped‐pinned thin‐walled open‐profile bars
Authors: McGee Oliver G.
Published: November 2005

Exact natural frequencies are determined for the torsional vibration of pretwisted thin‐walled open‐profile bars having torsionally clamped and pinned end restraints. The equation of motion and boundary conditions are derived from a multifilament model of a pretwisted thin‐walled bar undergoing warp deformation and a moderately large twist about the elastic axis. Closed‐form torsional frequencies and mode shapes are derived from the linear terms of the resulting non‐linear equations. As the length‐to‐leg ratio (L/b) and leg‐to‐thickness ratio (b/t) of typical open‐profile bars are varied, the individual and collective effects of warping and pretwist on the non‐dimensional torsional frequencies are demarcated. In addition, the closed‐form solutions offered here reveal considerable destiffening of the torsional frequencies due to warping‐pretwist coupling present in thin‐walled bars having pretwisted, unsymmetrical, open‐profiles and torsionally clamped and pinned end restraints. This coupling effect, which have been ignored in thin‐walled bar vibration theories hitherto, is brought out by the Wagner effect and warping shear stresses acting on the profiles.
On the performance of two tangent operators for finite element analysis of large deformation inelastic problems
Authors: M. Arif Abul Fazal , Zabaras Nicholas
Published: November 2005

An important step in the solution of non‐linear deformation problems using a Newton‐Raphson type of iterative scheme is the calculation of a tangent operator (the so‐called Jacobian) by linearizing the involved field equations. In this paper, full linearization of the virtual work equation is performed in an updated Lagrangian framework together with a calculation of the consistent linearized material moduli. To update the material state, a material frame indifferent two parameter integration scheme introduced earlier by the authors is used. In general, the reference configuration is updated after each iteration to coincide instantaneously with the present guess of the unknown equilibrium configuration. Another approach is to use the previous equilibrium state (at the beginning of a time step) as the reference configuration until the new equilibrium configuration at the end of the time step is found. The present paper explores the performance of two different Jacobians based on the above two approaches, with emphasis on their accuracy and convergence characteristics when large incremental steps are used. Finally, some details of their finite element implementation are given and results for several numerical tests including upset forging and extrusion of an axisymmetric billet are presented and discussed.
Vibrations of cantilevered skewed plates with corner stress singularities
Authors: McGee O. G. , Leissa A. W. , Huang C. S.
Published: November 2005

Accurate natural frequencies of skewed cantilevered thin plates are determined using the Ritz method. The present work is the first known vibrational study of the effects of stress singularities at the reentrant corner of skewed plates. In conjunction with classical thin plate theory, the Ritz trial space of assumed transverse displacement functions consists of algebraic polynomials, which are mathematically complete, and corner functions, which account for the singular behaviour of bending stresses at the reentrant corner. The corner functions were derived approximately four decades ago to study the nature of the stress singularities which occur at sharp interior corners or crack tips of typical plane elasticity and plate bending problems. Accurate non‐dimensional frequencies are calculated for thin plates having various side ratios and arbitrary degrees of skewness. Detailed numerical studies show that augmenting the Ritz trial space of polynomials with corner functions, having a co‐ordinate origin at the reentrant corner, enhances the convergence of the upper‐bound frequencies. The importance of using corner functions in skew plate vibrations is found to increase as the skew angle increases and as the side ratio decreases. Results obtained using the present method are compared with those obtained by other investigators using both theoretical and experimental methods.
Object oriented programming of the finite element method
Authors: Mackie R. I.
Published: November 2005

The finite element method is by its nature very modular. Object oriented programming enables full advantage to be taken of this modularity. This makes for safer and easier programming, and extending or modifying object oriented programs is very straightforward. The paper describes an object oriented implementation of the finite element method, and illustrates the advantages of the approach.
A general explicit or semi‐explicit algorithm for compressible and incompressible flows
Authors: Zienkiewicz O. C. , Wu J.
Published: November 2005

This note presents a rational basis for a unified finite element algorithm capable of dealing with a wide range of fluid flow in both steady and transient cases. It is hoped that empiricism inherent in many previous approaches can be avoided and a sound basis provided. The algorithm permits the use of equal interpolation for all variables by avoiding the need for the Babuska‐Brezzi constraints in regions where the flow is nearly incompressible.

The success of the algorithm, which here is written for the non‐conservative equation form, is demonstrated on several examples ranging from (nearly) incompressible through transonic regions to supersonic flows. Up to mild shocks such as those occurring in the examples presented in this paper, no 'artificial' viscosity is added at any stage.

The algorithm extends some concepts introduced in an earlier paper.
Real contact mechanisms and finite element formulation—a coupled thermomechanical approach
Authors: Zavarise G. , Wriggers P. , Stein E. , Schrefler B. A.
Published: November 2005

The solution of contact problems involves great numerical efforts to satisfy non‐penetration conditions. The search for numerical efficiency hence has limited the modelling of the real physical interface behaviour. Up to now mainly simple laws, usually formulated using constant coefficients, have been available to study contact problems in uncoupled from.

Here a thermomechanically coupled contact element is presented which accounts for the real microscopic shape of the surfaces, the microscopic mechanism of force transmission and heat exchange. The contact element geometrical behaviour has been put together with experimental and theoretical well founded micro‐mechanical and micro‐thermal laws adapted to Finite Element Method (FEM) necessities. Based on these laws the macroscopic related stiffnesses are calculated and continuously updated taking into account changes in significant parameters. The linearization of the set of equations has been obtained using a consistent technique which implies computational efficiency.
An element formulation for the classical finite difference and finite volume method applied to arbitrarily shaped domains
Authors: Lahrmann Andreas
Published: November 2005

Potential problems can be solved by analytical methods. However, for three‐dimensional structures of geometrically complex shape with non‐linear boundary conditions, numerical methods have to be applied. The most popular technique is the finite element method, which is used throughout the engineering community. The main advantage of this method lies in the application to arbitrarily shaped structures, which requires the use of non‐orthogonal meshes. More recently, the boundary element method has been proven to be a competitive tool in the field of potential problems.

In other research areas different numerical methods are used, for example in fluid mechanics the finite volume or the finite difference methods. But the application to irregularly shaped domains is difficult compared to the finite element and boundary element methods. The big drawback of these methods is not a poor numerical quality, but the absence of an element concept. In some cases, the results are even better compared to the other methods. Therefore, the main subject of this paper is the introduction of the element concept not only for the popular finite element method, but also for the finite difference and finite volume methods, which provides a high degree of geometric flexibility.
A knowledge‐based A‐priori approach to mesh generation in thermal problems
Authors: Kang E. , Haghighi K.
Published: November 2005

A new approach to the finite element mesh generation for two‐dimensional steady state thermal problems of conduction and convection is presented. Unlike other approaches, the proposed technique incorporates the information about the object geometry as well as the boundary and loading conditions to generate an a‐priori finite element mesh which is more refined around the critical regions of the problem domain. A blackboard architecture expert system is developed to intelligently identify critical regions and to choose the proper mesh size for them by performing an approximate heat flux calculation. From the results of the blackboard system, nodes are generated in the problem domain using the new concept of wave propagation. The wave propagation technique is fully automatic and does not require any user‐provided information except the data which define the object geometry and boundary conditions. After nodes are generated, well‐shaped triangular elements are formed ensuring the Delaunay property. During the triangulation process and to reduce the computation time for checking the overlapping problem, a new and efficient algorithm is proposed which defines a certain range only in which a potential triangular element might overlap the previously generated elements and boundary segments. Several examples are presented and discussed. When incorporated into and compared with the traditional approach to the adaptive finite element analysis, it is expected that the proposed approach, which starts the process with near‐optimal initial meshes, will result in lower levels of error and faster convergence of the solution to the desired accuracy in less time and at less cost.
Non‐linear finite strip analysis of rectangular laminates under end shortening, using classical plate theory
Authors: Dawe D. J. , Lam S. S. E. , Azizian Z. G.
Published: November 2005

The finite strip method is developed for predicting the geometrically non‐linear response of rectangular composite laminates with simply supported ends when subjected to uniform end shortening in their plane. At the loaded ends lateral in‐plane expansion may be allowed freely or may be prevented completely in different versions of the approach. The permitted laminate material properties are quite general, encompassing anisotropy and full coupling between in‐plane and out‐of‐plane behaviour. The analysis is based on the use of the classical plate theory and the non‐linearity is introduced in the strain‐displacement equations in the manner of the von Karman assumptions. Three different types of finite strip are presented with either linear, quadratic or cubic interpolation of the membrane displacement components across a strip: in each case the bending displacement component varies cubically across a strip. Results are presented for isotropic plates and for unsymmetric cross‐ply, angle‐ply and arbitrary laminates.
An explicit unconditionally stable variable time‐step method for one‐dimensional stefan problems
Authors: Zerroukat M. , Chatwin C. R.
Published: November 2005

Modelling of heat conduction processes with phase changes benefits from the application of variable time‐step methods when the behaviour of the moving boundary is not knowna prioiri. Due to convergence and stability constraints only implicit difference equations have been used with these methods. Implicit methods show a significant loss of accuracy and exhibit convergence difficulties when used for relatively slow or rapid moving‐boundary problems. To overcome these problems an improved explicit variable time‐step method which combines the explicit exponential difference equation and a variable time‐step grid network with virtual subspace increments around the moving boundary is presented and tested for both a solidification and a melting problem. A virtual subinterval time‐step elimination technique is incorporated to ensure that stability is automatically maintained for any mesh size. Unlike the implicit variable time‐step methods, the accuracy of the resulting method is not affected by the velocity of the moving boundary. For both test problems numerical results are in better agreement with known analytical solutions than results predicted by other numerical methods.
A multigrid method for the generalized symmetric eigenvalue problem: Part I—algorithm and implementation
Authors: Hwang T. , Parsons I. D.
Published: November 2005

A multigrid method is described that can solve the generalized eigenvalue problem encountered in structural dynamics. The algorithm combines relaxation on a fine mesh with the solution of a singular equation on a coarse mesh. A sequence of coarser meshes may be used to quickly solve this singular equation using another multigrid method. The hierarchy of increasingly finer meshes can be further exploited using a nested iteration scheme, whereby initial approximations to the fine mesh eigenvectors are computed using interpolated coarse mesh eigenvectors. The solution of some simple plate problems on a Convex C240 demonstrates the efficiency of a vectorized version of the multigrid algorithm.
Implementation of mixed time integration techniques on a vectorized computer with shared memory
Authors: Belytschko Ted , Gilbertsen Noreen D.
Published: November 2005

The implementation of subcycling in an explicit finite element program executed on a concurrent computer with shared memory is described. The effects of vectorization and parallelization on the speed‐up and efficiency achieved with subcycling is discussed. Numerical studies are presented to illustrate the effects of the number of processors, the size of element blocks and problem size. Finally, an efficient allocation algorithm which minimizes the effects of processor idleness is presented.
Thermoelastic stability of trusses with temperature‐dependent constitutive relations
Authors: Wriggers P. , Reese S.
Published: November 2005

This paper is concerned with stability problems of spatial trusses due to thermal and mechanical loading. A fully coupled thermomechanical truss element is formulated which accounts also for the temperature dependence of the constitutive parameters. The formulation leads to a non‐linear problem which is solved by the finite element method. The computation of critical points is based on the linearization of the coupled weak form which yields a non‐symmetric tangent operator. The formulation and its associated algorithmic treatment is validated by means of examples.
Theoretical optimization by genetic algorithm of delayed extraction parameters for a matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometer
Authors: Tauro S. , Razvi M. A. N.
Published: November 2005

This paper presents the application of a genetic algorithm (GA) to optimize the operating parameters, namely pulse voltage and extraction delay time, when using matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS). Simulations predict the presence of several combinations of these parameters that give a local maximum. The aim is to locate the optimal combination (a global maximum) of pulse voltage and extraction time delay in order to focus the ions of a particular m/z value to achieve the best resolution in a given instrumental geometry. The GA locates the global maximum quickly. The results indicate that it may be possible to achieve very high resolving power by using delayed extraction (DE)‐MALDI‐TOFMS with parameters obtained from the GA. Copyright © 2005 John Wiley & Sons, Ltd.
Application of stable isotope labeled glutathione and rapid scanning mass spectrometers in detecting and characterizing reactive metabolites
Authors: Mutlib Abdul , Lam Wing , Atherton Jim , Chen Hao , Galatsis Paul , Stolle Wayne
Published: November 2005

The formation of reactive metabolites from a number of compounds was studied in vitro using a mixture of non‐labeled and stable isotope labeled glutathione (GSH) as a trapping agent. GSH was labeled by incorporating [1,2‐13C2,15N]glycine into the tripeptide to give an overall increase of 3 Da over the naturally occurring substance. Detection and characterization of reactive metabolites was greatly facilitated by using the data‐dependent scanning features of the linear ion trap mass spectrometers to give complimentary and confirmatory data in a single analytical run. A comparison was made by analyzing the samples simultaneously on a triple‐stage quadrupole mass spectrometer operated in the constant neutral loss mode. The compounds studied included 2‐acetamidophenol, 3‐acetamidophenol, 4‐acetamidophenol (acetaminophen), and flufenamic acid. GSH adducts for each of these compounds produced a characteristic pattern of ‘twin ions’ separated by 3 Da in the mass spectral data. This greatly facilitated the detection and characterization of any GSH‐related adducts present in the microsomal extracts. Furthermore, characterization of these adducts was greatly facilitated by the rapid scanning capability of linear ion trap instruments that provided full‐scan, MS/MS and MS3 data in one single analysis. This method of detecting and characterizing reactive metabolites generated in vitro was found to be far superior to any of the existing methods previously employed in this laboratory. The combination of two techniques, stable isotope labeled glutathione and linear ion traps, provided a very sensitive and specific method of identifying compounds capable of producing reactive metabolites in a discovery setting. The complimentary set of mass spectral data (including full‐scan, MS/MS and MS3 mass spectra), obtained rapidly in a single analysis with the linear ion trap instruments, greatly accelerated identification of metabolically bioactivated soft spots on the molecules. This in turn enabled chemists to rapidly design out the potential metabolic liability from the back‐up compounds by making appropriate structural modifications. Copyright © 2005 John Wiley & Sons, Ltd.
Psychophysical Tuning Curves in Subjects with Tinnitus Suggest Outer Hair Cell Lesions
Authors: Mitchell Curtin R. , Creedon Thomas A.
Published: November 2005

A study by Penner (J Speech Hear Res 1980;23:779‐86) found evidence for Impaired lateral suppression in subjects with tinnitus and sensorineural hearing loss. If lateral suppression is related to tuning curve sharpness and lateral suppression is impaired, the shape of the tuning curve should be affected. The purpose of this study was to determine whether subjects with tinnitus have psychophysical tuning curves that are different from those of subjects without tinnitus. Psychophysical tuning curves and hearing thresholds were obtained from 18 subjects, 7 with tinnitus and 11 without tinnitus. Only subjects with normal audiograms (through 8 kHz) were selected for this study. In subjects with tinnitus psychophysical tuning curves were obtained in the region pitch‐matched to their tinnitus. In nontinnitus subjects psychophysical tuning curves were determined at the same frequencies as for the tinnitus subjects in a yoked‐control design. The slopes of the tails and tips and the Q10 and other measures were calculated for each tuning curve. The psychophysical tuning curves in subjects with tinnitus were significantly different (0.01 level) from those of control subjects and often had hypersensitive tails and some elevated tips. These shapes of tuning curves are consistent with cochlear lesions involving the loss of outer hair cells without damage to the Inner hair cells or nerve fibers.
Incidence of Adenovirus and Respiratory Syncytial Virus in Chronic Otitis Media with Effusion Using the Polymerase Chain Reaction
Authors: Shaw Collie B. , Obermyer Neal , Wetmore Stephen J. , Spirou George A. , Farr R. Wesley
Published: November 2005

The aim of this study is to investigate the role of adenovirus and respiratory syncytial virus in the cause of chronic otitis media with effusion by use of the polymerase chain reaction for detection. The polymerase chain reaction has proved to be more sensitive and specific than viral cultures and immunoassays in the detection of viruses in other specimens. Adenovirus and respiratory syncytial virus were chosen because these viruses have been the most commonly isolated viruses in middle ear effusions in studies using other techniques. The effusions (132 total) were sterilely collected from 88 children undergoing myringotomy and ventilation tube placement for chronic otitis media with effusion. Nine (6.8%) specimens were positive for adenovirus by the polymerase chain reaction, and 13 (9.9%) were positive for respiratory syncytial virus by the polymerase chain reaction. Only one specimen was positive for adenovirus and respiratory syncytial virus by viral culture and immunofluorescence, respectively. Our results show that the polymerase chain reaction can be used to detect adenovirus and respiratory syncytial virus in chronic middle ear effusions and that PCR is more sensitive than viral culture and immunofluorescence techniques.
Receptors for Glucocorticoids in the Human Inner Ear
Authors: Rarey Kyle E. , Curtis Lisa M.
Published: November 2005

Glucocorticoid receptors were detected in the human inner ear. The highest concentration of glucocorticoid receptor protein was measured by enzyme‐linked immunosorbent assay in the spiral ligament tissues; the lowest concentration of glucocorticoid receptors was measured in the macula of the saccule. The demonstration of the presence of glucocorticoid receptors in human inner ear tissues provides a basis to consider the direct effects of glucocorticoid action on select inner ear cells, rather than assuming a systemic antiinflammatory or immunosuppressive effect during the therapeutic treatment of patients with given inner ear disorders.
How to Systematically Review the Medical Literature
Authors: Rosenfeld Richard M.
Published: November 2005

In contrast to traditional narrative reviews, systematic reviews are true hypothesis‐driven research. Meta‐analysis is a form of systematic review in which studies are selected and combined by use of a predefined protocol to reduce bias and subjectivity. A sensitivity analysis shows how results vary through the use of different assumptions, tests, and criteria. The most valid synthesis of information occurs when published and unpublished materials are subjected to the same rigorous evaluation and when results are calculated with and without unpublished sources of data. A good systematic review captures the reader's attention through a skillful blend of numbers and narrative and qualifies for publication as original research in a peer‐reviewed journal. Otolaryngologists have published systematic reviews of varying quality since 1990. This article should help improve the quality and validity Of future efforts.
International Court of Justice Firmly Walled in the Law of Power in the Israeli–Palestinian Peace Process
Authors: DE WAART PAUL J. I. M.
Published: November 2005

The impartial and nearly unanimous advisory opinion by the International Court of Justice in the Wall case put the role of politics and diplomacy in the settlement of the Israeli–Palestinian conflict in its proper place, within the context of the rule of law. The significance of the opinion goes far beyond the illegality of the construction of the wall in the Occupied Palestinian Territories (OPT). The Court wisely and courageously seized the opportunity of its first direct involvement in the conflict to speak in plain legal terms about the tricky political problems that have ruined the Israeli–Palestinian peace process. It ascertained the present responsibility of the United Nations to protect Palestine's statehood. It affirmed the applicability of the prohibition of acquisition of Palestinian territory by Israel and confirmed the illegality of the Israeli settlements in the OPT. Moreover, the existence of the Palestinian people as the rightful claimant to the OPT is no longer open to question. One may only regret that the UN was not able to ask the Court to throw light on the Palestinian question at a much earlier stage.
The Second Srebrenica Trial: Prosecutor v. Vidoje Blagojević and Dragan Jokić
Authors: GALLAGHER KATHERINE
Published: November 2005

In its judgment issued on 17 January 2005, in Prosecutor v. Vidoje Blagojević and Dragan Jokić, Trial Chamber I, Section A, found that genocide had been committed against the Bosnian Muslim population following the fall of the Srebrenica ‘safe area’ in July 1995. The Trial Chamber's findings that forcible transfer, when combined with other acts, can constitute an underlying act of genocide (namely, causing serious mental harm to members of a group) contributes to a growing body of jurisprudence on genocide. The Trial Chamber found the accused guilty of such serious crimes as complicity in genocide, extermination, persecutions and murder. It determined that the appropriate mode of liability for each was aiding and abetting rather than committing through participation in a joint criminal enterprise, Accordingly the Trial Chamber sentenced Vidoje Blagojević to 18 years' imprisonment and Dragan Jokić to nine years' imprisonment.
The High Level Panel Report on Threats, Challenges and Change and the Future Role of the United Nations Security Council
Authors: MANUSAMA KENNETH M.
Published: November 2005

The UN High Level Panel Report, published in December, takes a comprehensive approach and is very frank in analysing the threats to international peace and security and their rootcauses. Its analysis and recommendations range from economic and social challenges to the use of force. This article discusses in particular the role and tasks that the High Level Panel envisages for the Security Council in light of the threats and challenges it identified. With the events of 11 September 2001 as the pivotal moment in history, the Panel nevertheless does not recommend or insist on fundamental changes of international legal paradigms, including in the (collective) use of force. The Panel's focus on reform of Security Council composition instead of the system that it operates neglects the problems with the latter and the impossibility of achieving the former.
A quest for WTO's legitimacy
Authors: CHO SUNGJOON
Published: November 2005

The WTO Consultative Report, dubbed the ‘Sutherland Report’ (the Report), was released on 17 January 2005 in an attempt to identify the WTO's institutional challenges, to provide non-binding recommendations from eminent persons, and thus to trigger a ‘process of reflection’. While these challenges (and criticism) vary, they are inextricably linked to the fundamental question of the legitimacy of WTO as a system, not necessarily as a mere gathering of 148 Members. In fact, the question has hotly been debated ever since the WTO's creation, generating a great deal of debates and reactions among scholars and politicians alike.
Investigating pressure effects on structural and dynamical properties of liquid methanol with many-body interactions
Authors: Wick Collin D. , Dang Liem X.
Published: November 2005

Molecular-dynamics simulations utilizing a many-body potential was used to study the pressure dependence of structural and dynamical properties for liquid methanol. The liquid density as a function of pressure agreed well with experiment, and a combination of radial and angular distribution functions were used to analyze molecular structure. From these distribution functions, it was observed that hydrogen bond strength increased with increasing pressure. This observation coincided with an increase in the molecular dipole as a function of pressure, having a significant effect on the observed increased hydrogen bond strength. Also, methanols were found to more strongly favor exactly two hydrogen bonds, with fewer methanols of zero, one, or three hydrogen bonds present at higher pressures. Furthermore, a majority of the compression with increased pressure was found to occur in regions perpendicular to the methanol hydrogen-oxygen bond vector. This was the case despite hydrogen-oxygen nonbonded distances between hydrogen bonding species being shorter, but their stiffer oxygen-hydrogen-(nonbonded) oxygen angle offsets this, resulting in their oxygen-oxygen distances being relatively unaffected. The methanol translational diffusion decreased significantly with increased pressure, while the rotational diffusion decreased at a similar magnitude around the oxygen-hydrogen and oxygen-carbon bond vectors, despite having very different overall diffusion. Finally, the hydrogen bond lifetime increased significantly with pressure, owing to the increased hydrogen bond strength, and the slower translational and rotational dynamics.
Histogram analysis as a method for determining the line tension of a three-phase contact region by Monte Carlo simulations
Authors: Djikaev Yuri
Published: November 2005

A method is proposed for determining the line tension, which is the main physical characteristic of a three-phase contact region, by Monte Carlo (MC) simulations. The key idea of the proposed method is that if a three-phase equilibrium involves a three-phase contact region, the probability distribution of states of a system as a function of two order parameters depends not only on the surface tension, but also on the line tension. This probability distribution can be obtained as a normalized histogram by appropriate MC simulations, so one can use the combination of histogram analysis and finite-size scaling to study the properties of a three phase contact region. Every histogram and results extracted therefrom will depend on the size of the simulated system. Carrying out MC simulations for a series of system sizes and extrapolating the results, obtained from the corresponding series of histograms, to infinite size, one can determine the line tension of the three phase contact region and the interfacial tensions of all three interfaces (and hence the contact angles) in an infinite system. To illustrate the proposed method, it is applied to the three-dimensional ternary fluid mixture, in which molecular pairs of like species do not interact whereas those of unlike species interact as hard spheres. The simulated results are in agreement with expectations.
Diffusion of oxygen tracer into deuterium-gas-baked IrOx∕Pb(Zr,TiO3)Pt capacitors and Pb(Zr,Ti)O3Pt films
Authors: Cross J. S. , Kurihara K. , Haneda H.
Published: November 2005

Deuterium gas (D2) ambient heat treatment of ferroelectric Pb(Zr,Ti)O3 (PZT) thin-film capacitors with a top electrode of iridium oxide and a bottom electrode of platinum showed significant polarization loss when baked at 200°C at a pressure of 5Torr. The D2 gas treatment of the capacitors partially reduced the iridium oxide (IrOx, where x is 1<x<2) film and increased surface roughness. In addition, a deuterium concentration [D] of 1020at.∕cm3 in the degraded PZT was measured with secondary-ion mass spectroscopy (SIMS). Subsequently, the degraded films were annealed at 550°C in oxygen (O216) and oxygen tracer (O218) gases which recovered the ferroelectric properties and the D concentration in the PZT decreased to the detection level of 1017at.∕cm3. The oxygen tracer concentration was highest in the IrOx film and much lower in the PZT. Comparison of the oxygen tracer SIMS profiles of the PZT annealed in tracer oxygen or preannealed in oxygen followed by oxygen tracer annealing showed little difference in the calculated PZT oxygen tracer diffusion coefficient of 5×10−15cm2∕s. If the PZT was reduced by the D2 gas, an increase in the oxygen diffusion coefficient would be expected as has been proposed in the literature, but this was not observed experimentally. These results indicate that the loss of polarization in the PZT capacitor is primarily due to the inhibition of ferroelectric domain switching by possible formation of [OD−].
Current-induced rotation of helical molecular wires
Authors: Král Petr , Seideman Tamar
Published: November 2005

We show that electric current running through a nanojunction with a biased helical molecule can induce unidirectional rotation of the molecular component. In an electric field, conduction electrons injected into the molecule are accelerated along the helical path going through its body, thereby gaining directed angular momentum. Conservation laws require that an angular momentum of the same size but opposite sense is imparted to the rigid-body rotation of the helix. We describe the angular momentum exchange processes that underlie the operation of the nanorotor, discuss factors limiting its efficiency, and propose potential applications.
Sensitive dependence of hydrogen Balmer-alpha laser-induced fluorescence signal from hydrogen neutral beam on background magnetic field
Authors: Foley E. L. , Levinton F. M.
Published: November 2005

A previously unreported result for the dependence of a laser-induced fluorescence (LIF) signal from the H-alpha (Balmer-alpha) transition in a hydrogen neutral beam passing through a background of neutral hydrogen gas is presented. The LIF signal from a 30kV beam is found to be enhanced and the fine-structure line amplitudes in the H-alpha spectrum are seen to vary significantly with an applied perpendicular magnetic field over the range of 0–0.01T. The phenomenon has also been observed and investigated in a background electric field of ∼0–300V∕cm, and in the presence of crossed perpendicular magnetic and electric fields, demonstrating that the magnetic-field effect is due to the motional Stark electric field perceived in the beam reference frame as it passes through the magnetic field. The effect has been studied with variations of background neutral gas pressure, laser power, and polarization direction and at different locations along the neutral beamline. The phenomenon could be exploited as a low-field diagnostic technique in environments that are not appropriate for magnetic probes.
Dynamic redistribution of the electric field of the channel in AlGaN∕GaN high electron mobility transistor with nanometer-scale gate length
Authors: Vitusevich S. A. , Danylyuk S. V. , Kurakin A. M. , Klein N. , Lüth H. , Petrychuk M. V. , Belyaev A. E.
Published: November 2005

Transport peculiarities and the physical origin of noise properties in AlGaN∕GaN-based high electron mobility transistors (HEMTs) with a large ratio of channel length to gate length were investigated. Dependence of deviations of low-frequency noise spectra from the 1∕f law on applied gate voltages was studied in an extended range of frequencies. The behavior is explained in terms of a model based on the dynamic redistribution of the electric field along the two-dimensional channel of the HEMT. The results show that the main contribution to the noise originates from the region under the gate and adjacent to the gate channel regions.