bluuebunny/crossref_metadata_2025 huggingface dataset:
Perception of Computer‐tailored Feedback for Smoking Cessation: Qualitative Findings from Focus Groups
Authors: Gilbert Hazel , Nazareth Irwin , Sutton Stephen
Published: April 2009

Tobacco smoking continues to be a major public health problem. Few smokers present themselves for treatment, and it is important to offer a range of interventions that appeal to different individual needs and preferences. Computer‐tailored feedback can fill the gap between generic self‐help and intensive clinical therapy. Using focus groups, we investigated smokers' perceptions of generic self‐help materials and computer‐generated individually tailored feedback reports. Participants recognized the generic nature of self‐help material and welcomed the concept of personal support, but were concerned about some aspects of the material. Findings supported the continuation of the development and delivery of computer‐tailored feedback, but more research is warranted to optimize the content and style of the feedback for individual perceptions and expectations.
Parentage in natural populations: novel methods to detect parent‐offspring pairs in large data sets
Authors: CHRISTIE MARK R.
Published: April 2009

Parentage analysis in natural populations presents a valuable yet unique challenge because of large numbers of pairwise comparisons, marker set limitations and few sampled true parent–offspring pairs. These limitations can result in the incorrect assignment of false parent–offspring pairs that share alleles across multi‐locus genotypes by chance alone. I first define a probability, Pr(δ), to estimate the expected number of false parent–offspring pairs within a data set. This probability can be used to determine whether one can accept all putative parent–offspring pairs with strict exclusion. I next define the probability Pr(φ|λ), which employs Bayes’ theorem to determine the probability of a putative parent–offspring pair being false given the frequencies of shared alleles. This probability can be used to separate true parent–offspring pairs from false pairs that occur by chance when a data set lacks sufficient numbers of loci to accept all putative parent–offspring pairs. Finally, I propose a method to quantitatively determine how many loci to let mismatch for study‐specific error rates and demonstrate that few data sets should need to allow more than two loci to mismatch. I test all theoretical predictions with simulated data and find that, first, Pr(δ) and Pr(φ|λ) have very low bias, and second, that power increases with lower sample sizes, uniform allele frequency distributions, and higher numbers of loci and alleles per locus. Comparisons of Pr(φ|λ) to strict exclusion and CERVUS demonstrate that this method may be most appropriate for large natural populations when supplemental data (e.g. genealogies, candidate parents) are absent.
Ten novel microsatellite loci characterized for a remarkably widespread fish: Galaxias maculatus (Galaxiidae)
Authors: CARREA CECILIA , PATERSON IAN G. , CUSSAC VICTOR E. , RUZZANTE DANIEL E.
Published: April 2009

Ten polymorphic microsatellite markers (five tetra‐, one compound tetra‐, one octa‐ and three dinucleotides) were isolated and characterized for Galaxias maculatus, a fish species widely distributed in the Southern Hemisphere. Markers were tested in 89 individual samples from a single location and the number of alleles ranged between 2 and 28. Observed and expected heterozygosities ranged from 0.103 to 0.910 and 0.098 to 0.935 respectively. No evidence was detected for either linkage disequilibrium (P‐values > 0.05 for each locus pair) or deviations from HWE (P‐values > 0.05 for every loci).
Effects of Prednisone Alone or Prednisone with Ultralow‐Dose Aspirin on the Gastroduodenal Mucosa of Healthy Dogs
Authors: Heather Graham A. , Leib Michael S.
Published: April 2009

Background:The coadministration of prednisone and ultralow‐dose aspirin has been recommended for the management of various diseases, but the safety of this combination in dogs has not been studied.

Hypotheses:The gastroduodenal lesions associated with prednisone and ultralow‐dose aspirin administration will be similar to those caused by prednisone alone, but both treatments will result in more severe lesions than placebo.

Animals:Eighteen healthy adult purpose‐bred dogs.

Methods:Randomized, blinded, placebo‐controlled study of 3 treatment groups for 27 days: placebo, prednisone, and prednisone and aspirin. Gastroduodenoscopy was performed before and on days 5, 14, and 27 of treatment and mucosal lesions scores were assigned. Mucosal lesion scores were compared by a Kruskal‐Wallis test. Clinical signs were compared by the Friedman's chi‐square test (significance atP< .05).

Results:There were no significant differences in the gastroduodenal lesion scores among groups, or within groups at any time during the study. Significantly more dog‐days of diarrhea occurred in the prednisone and aspirin group during treatment, compared with baseline. No significant differences in clinical signs were found among any of the groups.

Conclusion:The concurrent use of prednisone and ultralow‐dose aspirin did not increase the severity of gastroduodenal lesions compared with prednisone or placebo. Coadministration of prednisone and ultralow‐dose aspirin increases the frequency of mild, self‐limiting diarrhea in some dogs.
A Parametric Study of the Blade Row Interaction in a High Pressure Turbine Stage
Authors: Persico G. , Gaetani P. , Osnaghi C.
Published: April 2009

An extensive experimental analysis on the subject of the unsteady periodic flow in a high subsonic high pressure (HP) turbine stage has been carried out at the Laboratorio di Fluidodinamica delle Macchine of the Politecnico di Milano (Italy). In this paper the aerodynamic blade row interaction in HP turbines, enforced by increasing the stator and rotor blade loading and by reducing the stator-rotor axial gap, is studied in detail. The time-averaged three-dimensional flowfield in the stator-rotor gap was investigated by means of a conventional five-hole probe for the nominal (0 deg) and highly positive (+22 deg) stator incidences. The evolution of the viscous flow structures downstream of the stator is presented to characterize the rotor incoming flow. The blade row interaction was evaluated on the basis of unsteady aerodynamic measurements at the rotor exit, performed with a fast-response aerodynamic pressure probe. Results show a strong dependence of the time-averaged and phase-resolved flowfield and of the stage performance on the stator incidence. The structure of the vortex-blade interaction changes significantly as the magnitude of the rotor-inlet vortices increases, and very different residual traces of the stator secondary flows are found downstream of the rotor. On the contrary, the increase in rotor loading enhances the unsteadiness in the rotor secondary flows but has a little effect on the vortex-vortex interaction. For the large axial gap, a reduction of stator-related effects at the rotor exit is encountered when the stator incidence is increased as a result of the different mixing rate within the cascade gap.
An Approach for Inclusion of a Nonlocal Transition Model in a Parallel Unstructured Computational Fluid Dynamics Code
Authors: Kožulović Dragan , Lapworth B. Leigh
Published: April 2009

The implementation of an integral transition model in a parallel unstructured computational fluid dynamics code is described. In particular, an algorithm for gathering the nonlocal boundary layer values (momentum thickness and shape factor) from parallel distributed computational domains is presented. Transition modeling results are presented for a flat plate and for a low pressure turbine, covering a large variation of Reynolds numbers, Mach numbers, turbulence intensities, and incidence angles. Contrary to fully turbulent simulations, transitional predictions are in very good agreement with measurements. Furthermore, the computational overhead of transitional simulations is only 7% for one multigrid cycle.
Developments in Hot-Streak Simulators for Turbine Testing
Authors: Povey Thomas , Qureshi Imran
Published: April 2009

The importance of understanding the impact of hot-streaks, and temperature distortion in general, on the high pressure turbine is widely appreciated, although it is still generally the case that turbines are designed for uniform inlet temperature—often the predicted peak gas temperature. This is because there is an insufficiency of reliable experimental data both from operating combustors and from rotating turbine experiments in which a combustor representative inlet temperature profile has accurately been simulated. There is increasing interest, therefore, in experiments that attempt to address this deficiency. Combustor (hot-streak) simulators have been implemented in six rotating turbine test facilities for the study of the effects on turbine life, heat transfer, aerodynamics, blade forcing, and efficiency. Three methods have been used to simulate the temperature profile: (a) the use of foreign gas to simulate the density gradients that arise due to temperature differences, (b) heat exchanger temperature distortion generators, and (c) cold gas injection temperature distortion generators. Since 2004 three significant new temperature distortion generators have been commissioned, and this points to the current interest in the field. The three new distortion generators are very different in design. The generator designs are reviewed, and the temperature profiles that were measured are compared in the context of the available data from combustors, which are also collected. A universally accepted terminology for referring to and quantifying temperature distortion in turbines has so far not developed, and this has led to a certain amount of confusion regarding definitions and terminology, both of which have proliferated. A simple means of comparing profiles is adopted in the paper and is a possible candidate for future use. New whole-field combustor measurements are presented, and the design of an advanced simulator, which has recently been commissioned to simulate both radial and circumferential temperature nonuniformity profiles in the QinetiQ/Oxford Isentropic Light Piston Turbine Test Facility, is presented.
Static Analysis of Shells With Developable Middle Surfaces
Authors: Krivoshapko S. N.
Published: April 2009

This review article is devoted to an analysis of the literature on the stress-strain state of shells with developable middle surfaces. Wide choices of design methods for the developable surfaces provide not only the necessary shapes and special properties; they also prove to be convenient to apply. Representative examples are given for the static analysis of thin elastic shells by both analytic and numerical methods. Generally, the curvilinear non-orthogonal conjugate coordinates of the developable middle surface are used. Lines of principal curvatures are used as coordinates only for the strength analysis of thin shells in the form of Monge’s ruled surfaces. It is shown that momentless and moment theories give similar results if certain conditions are met a priori. The parabolic (isometric) bending of thin developable shells is also analyzed. This review article contains 97 references.
Gas Bubbles and Their Influence on Microorganisms
Authors: Chalmers Jeffrey J.
Published: April 2009

A review of the interactions of microorganisms and bubbles is presented. Particular emphasis is given to the damage that results when gas bubbles are introduced into animal and insect cell culture medium. The mechanism of this damage is presented as well as a discussion of the protective additives that have been found to reduce cell damage from gas bubbles. This review article has 43 references.
Review of Eigensolution Procedures for Linear Dynamic Finite Element Analysis
Authors: Bertolini Adrian F.
Published: April 2009

This article reviews the solution procedures used to extract eigenvalues and eigenvectors from linear dynamic systems using the finite element method. The main focus of this review article is on eigensolution techniques that provide only a partial eigensolution. Such eigensolvers extract only a small subset (normally the lowest) of the eigenvalues and eigenvectors present in the discretized system. They represent the most efficient approach to extracting eigenvalues and eigenvectors from large degree of freedom systems. The techniques covered include the subspace iteration method, the Lanczos method, the conjugate gradient method, the Ritz vector method, the substructure synthesis methods (including component mode synthesis), and the condensation techniques (including dynamic substructuring). Each subsection contains a variety of references that cover the current state of research as well as the origin of each technique. A brief critique of the eigensolution procedures used for solving small (less than 250 degree of freedom) eigenproblems is also included for completeness. The discussion is generally limited to eigensolution techniques for linear undamped eigenproblems of the form AΦ = CΦΛ, where A and C are frequently symmetric and positive definite. A brief review of eigensolvers for the nonsymmetric eigenproblem, such as that arising in damped structures, is included at the end. This review article contains 320 references.
A Panoramic Overview of the Principles and Equations of Motion of Advanced Engineering Dynamics
Authors: Papastavridis John G.
Published: April 2009

This is a qualitative and concise review of the fundamental principles and equations of Lagrangean, or Analytical, Mechanics (AM) for discrete (or discretizable) and constrained systems; primarily for theoretically-oriented engineers, but also for physicists and mathematicians. In spite of the age and obvious importance of the subject, no other comparable presentation of it seems to exist in the English language literature. Most contemporary treatments of advanced mechanics are either too formalistic and abstract, and as such are virtually inaccessible to engineers; or are of the multibody dynamics variety and hence, perhaps unavoidably, narrow in scope in their treatment of the fundamentals and general methods pertaining to AM. There are 109 references.
Nonlinear Waves in Nonlocal Media
Authors: Engelbrecht J. , Braun M.
Published: April 2009

This review article gives a brief overview on nonlocal theories in solid mechanics from the viewpoint of wave motion. The influence of two essential qualities of solids—nonlocality and nonlinearity—is discussed. The effects of microstructure are analyzed in order to understand their role in nonlocal theories. The various models are specified on the level of one-dimensional unidirectional motion in order to achieve mathematical clarity of interpreting physical phenomena. Three main types of evolution equations are shown to govern deformation waves under such assumptions. Based on the dispersion analysis, weak, true, and strong nonlocalities are distinguished. There are 75 references included with this article.
Scaling of Structural Failure
Authors: Bazˇant Zdeneˇk P. , Chen Er-Ping
Published: April 2009

This article attempts to review the progress achieved in the understanding of scaling and size effect in the failure of structures. Particular emphasis is placed on quasibrittle materials for which the size effect is important and complicated. After reflections on the long history of size effect studies, attention is focused on three main types of size effects, namely the statistical size effect due to randomness of strength, the energy release size effect, and the possible size effect due to fractality of fracture or microcracks. Definitive conclusions on the applicability of these theories are drawn. Subsequently, the article discusses the application of the known size effect law for the measurement of material fracture properties, and the modeling of the size effect by the cohesive crack model, nonlocal finite element models and discrete element models. Extensions to compression failure and to the rate-dependent material behavior are also outlined. The damage constitutive law needed for describing a microcracked material in the fracture process zone is discussed. Various applications to quasibrittle materials, including concrete, sea ice, fiber composites, rocks and ceramics are presented. There are 377 references included in this article.
Dynamic Characteristics of Magnetically-Levitated Vehicle Systems
Authors: Cai Y. , Chen S. S.
Published: April 2009

The dynamic response of magnetically-levitated (maglev) ground transportation systems has important consequences for safety and ride quality, guideway design, and system costs. This article, which reviews various aspects of the dynamic characteristics, experiments and analysis, and design guidelines for maglev systems, discusses electrodynamic system (EDS) maglev vehicle stability, motion-dependent magnetic force components, guideway characteristics, vehicle/guideway interaction, ride quality, suspension control laws, aerodynamic loads and other excitations, and research needs. This review article includes 157 references.
Transient Resonance Scattering and Target Identification
Authors: Gaunaurd G. C. , Strifors H. C.
Published: April 2009

The article presents an overview of transient resonance scattering, emphasizing one of its most important applications—the active classification of sonar and radar targets. It discusses traditional, classical techniques such as the Watson-Sommerfeld method (WSM) to transform classical, and slowly convergent normal-mode series in the frequency domain, to rapidly convergent series in the domain of the complex generalization, λ, of the mode-order, n. In view of its analytical complexity and the advent of computers that can overcome slow convergence difficulties, the WSM is not as popular today as it once was. Its main advantage remains its ability to extract physical interpretations from the mathematical results. Resonance scattering focuses on the resonance spectral region of targets. Of these, the penetrable (ie, elastic or dielectric) ones are the subjects of main interest here, particularly those insonified/illuminated by (finite) pulses of various types. The authors describe the exact isolation and extraction of the resonances contained within the scattering cross-section of a penetrable target by subtraction of suitable, background, geometrical contributions. These backgrounds are often given by the solution for an identical, but impenetrable target. This seems to be the main usefulness of impenetrable target solutions in underwater acoustics, which, generally, are physically unrealistic idealizations. The resonances identify the target as its fingerprint. Examples are shown to illustrate various transient scattering phenomena in acoustics and electromagnetism. The article shows exactly how the broadband pulses emitted by an impulse sonar (or radar) extract a substantial number of resonances from the echoes of penetrable targets. Further, it is shown how these are actually used to identify all physical characteristics of various analyzed targets, thus, indeed identifying them. The application of a novel signal processing technique that analyzes the echoes in the joint time-frequency domain is examined. This shows much promise for target identification purposes. Many distributions of the Wigner-type were used by us to generate simulated and experimental echo-displays in time-frequency that show the advantages of the process. The present overview supplements two earlier ones [23, 48] on closely related subjects. The article includes 101 references.
Mathematical Modeling of Dusty-Gas Boundary Layers
Authors: Osiptsov A. N.
Published: April 2009

This article reviews the state of the art in the mathematical modeling of dusty-gas laminar boundary layers in the framework of the two-fluid approach. Main attention is paid to the strict formulation of the two-phase boundary layer approximation, using the matched asymptotic expansion method. The low and high-velocity boundary layers both on curve and flat surfaces are considered. The particle accumulation in the boundary layers and the effects of particles on the friction and heat fluxes are examined. Important advances in the field of study are summarized and the areas deserving further development are discussed. This review article has 107 references.
Vibration of Shallow Shells: A Review With Bibliography
Authors: Liew K. M. , Lim C. W. , Kitipornchai S.
Published: April 2009

This review article documents recent developments in the free vibration analysis of thin, moderately thick, and thick shallow shells. An introductory review of the studies in Kirchhoff-Love classical thin shell theory is given. The development of studies in moderately thick shells incorporating the effects of transverse shear deformation and rotary inertia is detailed. This review article mainly focuses on research advances in vibration studies since the 1970s using the classical Kirchhoff-Love, first-order, and higher-order theories. The validity and range of applicability of these theories are examined. There are 163 references listed at the end of the article.
Computational Approaches With Applications to Non-Classical and Classical Thermomechanical Problems
Authors: Tamma Kumar K. , Namburu Raju R.
Published: April 2009

Although the issues are not very controversial, the fusion of both the fields of heat conduction in solids and elasticity which results in the so-called field of dynamic thermoelasticity (both non-classical and classical), dates as far back as Maxwell (1867), and has long been a subject matter of widespread research activity and interest. Although routine thermomechanical problems are primarily influenced by classical effects, issues where non-classical influences may become important are also addressed. To date, numerous applications ranging from defense, aerospace to manufacturing related problems including routine mechanical, civil, nuclear and allied engineering applications influenced by thermal-structural interactions continue to pose significant challenges both from the underlying mechanics and from a computational viewpoint. Herein is first presented an overview of non-classical and classical dynamic thermoelasticity models and equations governing these situations. Subsequently, attention is focused on computational approaches for the modeling and analysis of various classes of problems encompassing thermal-structural interactions which can be broadly classified as: i) thermally-induced stress wave propagation problems, ii) thermally-induced dynamic (inertial type) problems, and iii) the general field of thermal stresses. A variety of illustrative numerical examples encompassing non-classical and classical influences are finally presented to provide an improved understanding of the behavior of thermal-structural problems via effective unified computational developments. This review article contains 142 references.
Random Vibration of Thermally Buckled Plates: II Nonzero Temperature Gradient Across the Plate Thickness
Authors: Lee John
Published: April 2009

As a theoretical tool, we use the single-mode Fokker-Planck distribution for an isotropic plate to describe the random vibration of thermally buckled composite plates. The Fokker-Plank distribution becomes singular as uniform plate temperature far exceeds, say, 20 times the critical buckling temperature. Then the asymptotic high-temperature moments depend only on the snap-through displacement, testifying that stochastic dynamics has degenerated into a static snap-through problem in the limit of high plate temperature and large temperature gradient across the plate thickness. Otherwise, it is nonsingular and bimodal for low and moderate plate temperatures. From the nonsingular Fokker-Planck distribution, we have deduced peak scaling by the standard deviation of displacement distribution and derived a functional form for strain distribution by using the quadratic relation between strain and displacement. They have been validated by the displacement histograms of numerical simulations and the strain histograms of thermally buckled plate experiments.
Simulation-Based Development of Heuristic Strategies for Complex System Convergence
Authors: McCulley C. , Hulme K. , Bloebaum C. L.
Published: April 2009

The feasibility of system-level optimization in complex engineering design rests on the capability to iteratively converge a system of coupled subprocesses in a reasonable amount of time and at a reasonable cost. Each of these subprocesses, or modules, has an individual time and cost to execute. Convergence strategies are systems of rules for executing through the set of modules. Strategies can be developed which draw information from system characteristics to reduce the overall time and cost of converging the system. A simulator has been created which combines automatic model building and sequencing capability with an engine capable of running either sequential or parallel execution strategies. Several first generation strategies, both sequential and parallel, are explored using this technique.
Design Tool for Base-Isolated Structures Modeled as Single-Degree-of-Freedom Oscillators
Authors: Maldonado Gustavo O.
Published: April 2009

A stochastic equivalent linearization technique combined with a ground response spectrum approach is proposed to approximate the inelastic response of base-isolated structures. These structures are modeled by nonlinear oscillators with a single degree of freedom. The main advantage of the proposed methodology is the fast calculation of approximate results in comparison with the slow, but more accurate time history analyses. The Bouc-Wen constitutive model is used to represent the inelastic behavior of the isolators. The equations of motion are linearized by an iterative stochastic technique involving the a-priori unknown response statistics. At each iteration step, the modal contributions from one real and one pair of complex conjugate modes are combined by a response spectrum approach to obtain the maximum responses of interest. The process requires the use of conventional spectra (pseudo-acceleration and relative velocity) as well as the relative displacement spectrum of a massless oscillator. Floor response spectrum results above the isolators are calculated by the proposed approach and are compared against the results obtained by a simulation involving time history analyses.
Cylindrical Shell Under Axial Impact: Super/Sub-Critical Impact Velocities at Constant Momentum
Authors: Mucino V. H. , Garel S. C. P. E. , Smith J. E.
Published: April 2009

The dynamic buckling response of a cylindrical shell under axial impact is considered in this study. Specifically, the effects of various combinations of mass and velocity on the response of the cylinder for constant (near critical) momentum. A rigid mass is affixed at one end of the cylinder and is impacted at the other end against an infinitely rigid wall. The boundary conditions are defined by considering the mass rigidly attached to one end, axial velocity towards the right wall, and simply supported contact interface conditions. An explicit finite element code is used (LS-DYNA3D), to determine the response of the shell as variations of mass and velocity are made for a given (near critical) momentum. Specifically, in the neighborhood of critical impact velocities.
Mechanical Degradation of Polymers in Flows Through Porous Media: Effect of Flow Path Length and Particle Size
Authors: Mu¨ller A. J. , Patruyo L. G. , Montano W. , Roversi-M. D. , Moreno R. , Rami´rez N. E. , Sa´ez A. E.
Published: April 2009

In this work, we present an experimental study of flow-induced degradation of hydrolyzed polyacrylamide in aqueous solutions flowing through porous media consisting of beds packed with monodisperse spherical particles. The degradation is analyzed by passing the solution repeatedly through the porous medium at a constant flow velocity, and then characterizing the degraded solution in terms of its resistance coefficient. Repeated passes through the porous medium are equivalent to increasing the path length of the solution. When the polyacrylamide is dissolved in deionized water, it exhibits a gradual extension thickening behavior in terms of increases in flow velocity. In this case, the polymer degrades as it passes through the porous medium, even at relatively low flow rates. When the polyacrylamide is dissolved in a NaCl solution, it exhibits critical extension thickening in porous media flows, and it only degrades at Reynolds numbers that are higher than the onset of the extension thickening behavior. With repeated passes, the polymer progressively degrades until an asymptotic value of resistance coefficient is reached. The results show that the effect of particle size on degradation rates depends on the basis used for comparison between experiments carried out in beds with different particle sizes. However, the degree of degradation achieved after long path lengths is always higher for the largest particle size employed under equivalent comparison parameters.
Exceedance Probabilities of MDOF-Systems Under Stochastic Excitation
Authors: Pradlwarter H. J. , Schue¨ller G. I.
Published: April 2009

A numerical procedure of evaluating the exceedance probabilities of MDOF-systems under non-stationary random excitation is presented. The method is based on a newly developed Controlled Monte Carlo simulation procedure applicable to dynamical systems. It uses “Double and Clump” to assess the low probability domain and employs further intermediate thresholds to increase the efficiency of MCS for estimating first passage probabilities. Applied to a hysteretic type of MDOF-system, the method shows good results when compared with direct MCS.
Frictional Effects in Unsteady Turbulent Pipe Flows
Authors: Wylie E. B.
Published: April 2009

In the simulation of rapid transient events in fluid-filled pipelines, the method of characteristics is recognized to provide reliable results during the first pressure excursion. However, if a long term oscillatory response of a rapid event is needed, traditional methods of evaluating viscous losses are inadequate in low Reynolds number turbulent flow events. This paper looks at a method to implement frequency-dependent viscous losses in the method of characteristics for turbulent flow and provides comparisons with experimental records.
Variational Solution for an Initial Conditions Problem
Authors: Filipich C. P. , Rosales M. B.
Published: April 2009

An initial conditions problem is addressed by first transforming it into a boundary value one. An appropriate functional and an extremizing sequence are proposed. The methodology has been previously named WEM (Whole Element Method) by the authors. In the present paper, this name is justified since division of the time domain is avoided even when loads with finite number of impulses of arbitrary duration are involved. The method is theoretically founded by theorems and corolaries. Their statements are included in the work. A numerical example of an undamped single degree of freedom (SDOF) system subjected to a rectangular impulse load is carried out. Comparison is made with the well-known classical solution.
Recent Engineering Applications in China on Coupling Boundary Elements With Finite Elements
Authors: Lei Xiaoyan , Du Qinghua
Published: April 2009

This review article deals with some recent investigations in China in coupling boundary elements (BEs) with finite elements (FEs) during the last decade. Two types of combination schemes are used for coupling the BEs with FEs are discussed. One is merging of FE to BE for the sake of high local stress or stress intensity factor computations. The other is coupling BE to FE for fitting BEs with infinite boundary requirements to the case of some complex local FEs computations. Fluid-solid interaction, and the impact response problem are examined by FE-BE coupling methods. The domain decomposition method of alternative FE and natural BE over unbounded domain, variational principles and transient problems in coupling FE-BE are also discussed. Several application examples in engineering practice solved by the combination of FE-BE are given. The results show that the combination of the two methods should be one of the feasible engineering design approaches to the structural analysis of complex structures or machinery. This review article contains 70 references.
Dynamics of Disordered Periodic Structures
Authors: Lin Y. K.
Published: April 2009

For functional or aesthetic reasons, many a structural system is designed to be spatially periodic; namely, it is composed of identical sub-units which are connected to form a spatially periodic pattern. The main construction of the hull of a ship, the fuselage of an aircraft, and a space antenna are examples. Such a structure possesses interesting dynamic properties. However, due to material, geometric and manufacturing variabilities, an ideally periodic structure does not exist. The departure from the ideal designed configuration is known as disorder, which can cause drastic change in the dynamic behavior. The present paper gives a review of some recent works on wave propagation and frequency response of disordered periodic structures, of interest to researchers on vibration and noise control.
Wave Localization in Multi-Coupled Periodic Structures: Application to Truss Beams
Authors: Pierre Christophe , Castanier Matthew P. , Chen Wan Joe
Published: April 2009

A tutorial and a review of recent developments in the area of localization in linear structural dynamics problems are presented. Particular emphasis is placed on multi-coupled nearly periodic structures, which carry more than one wave type. First, background on perfectly periodic structures is provided, including both the wave and modal descriptions of the dynamics. A wave transfer matrix formulation for disordered periodic structures is then presented, which is well suited to the analysis of localized dynamics. Next, stochastic analysis tools are introduced that allow one to quantify the degree of localization in an asymptotic sense. Means of calculating these localization factors as the Lyapunov exponents of the system wave transfer matrix are discussed. Finally, the general theory is illustrated on an example multi-coupled structure - a planar truss beam which carries four pairs of waves. The propagation of waves in the disordered structure is examined, and Lyapunov exponents are calculated. In addition to the localization of the incident wave, significant mixing of the various wave types occurs, causing the leakage of energy to the least localized waves, and enabling sustainment of motion according to the smallest Lyapunov exponent.
Computational Models for Sandwich Panels and Shells
Authors: Noor Ahmed K. , Burton W. Scott , Bert Charles W.
Published: April 2009

The focus of this review is on the hierarchy of computational models for sandwich plates and shells, predictor-corrector procedures, and the sensitivity of the sandwich response to variations in the different geometric and material parameters. The literature reviewed is devoted to the following application areas: heat transfer problems; thermal and mechanical stresses (including boundary layer and edge stresses); free vibrations and damping; transient dynamic response; bifurcation buckling, local buckling, face-sheet wrinkling and core crimping; large deflection and postbuckling problems; effects of discontinuities (eg, cutouts and stiffeners), and geometric changes (eg, tapered thickness); damage and failure of sandwich structures; experimental studies; optimization and design studies. Over 800 relevant references are cited in this review, and another 559 references are included in a supplemental bibliography for completeness. Extensive numerical results are presented for thermally stressed sandwich panels with composite face sheets showing the effects of variation in their geometric and material parameters on the accuracy of the free vibration response, and the sensitivity coefficients predicted by eight different modeling approaches (based on two-dimensional theories). The standard of comparison is taken to be the analytic three-dimensional thermoelasticity solutions. Some future directions for research on the modeling of sandwich plates and shells are outlined.
Buckling of Thin Shells: Recent Advances and Trends
Authors: Teng Jin Guang
Published: April 2009

This paper provides a review of recent research advances and trends in the area of thin shell buckling. Only the more important and interesting aspects of recent research, judged from a personal view point, are discussed. In particular, the following topics are given emphasis: (a) imperfections in real structures and their influence; (b) buckling of shells under local/non-uniform loads and localized compressive stresses; and (c) the use of computer buckling analysis in the stability design of complex thin shell structures.
Transformation-Induced Plasticity (TRIP)
Authors: Fischer F. D. , Sun Q.-P. , Tanaka K.
Published: April 2009

This review article attempts to explain TRIP generally and its appearance in different materials. Continuum mechanics formulations are mainly used to explain this phase change phenomenon. An overview is given of the published literature which is often not very easily accessible. Technological aspects are presented, such as constitutive equations of materials showing TRIP. Aspects of material selection and future material design are also treated. This article contains 315 references.
Modeling, Fabrication, and Testing of Micro Heat Pipes: An Update
Authors: Peterson G. P.
Published: April 2009

In 1992, an overview was presented which summarized the status and progress made in the development of very small, “micro” heat pipes, manufactured as stand alone devices or fabricated as an integral part of silicon wafers. Since that initial review, significant advances have been made in the analysis, fabrication and testing of these devices, for use in a wide variety of applications. Following, is a review of the more recent work in this rapidly emerging field. Included is a summary of the analytical techniques developed, the various proposed methods of fabrication, and a summary of the most current test results achieved to date. Because the fundamental operating characteristics of micro heat pipes larger than 1 mm in diameter are similar to that of conventional heat pipes, this review focuses on the analysis, fabrication, and testing of micro heat pipes with characteristic dimensions of less than 500 μm. Particular emphasis is placed on research, related to the development of arrays of micro heat pipes and flat plate micro heat pipes fabricated as an integral part of semiconductor devices.
Inverse Problems in Vibration - II
Authors: Gladwell Graham M. L.
Published: April 2009

This article reviews recent literature on inverse problems relating to the reconstruction or estimation of the physical properties of mechanical systems from a knowledge of (some of) their spectral and/or modal data. The review relates exclusively to small vibrations of mechanical systems. The literature is divided according to: the type of system, continuous or discrete, damped or undamped; the type of data, spectral, modal, nodal, complete or incomplete.
Stable Response of Non-Classically Damped Mechanical Systems - II
Authors: Nicholson David W. , Lin Baojiu
Published: April 2009

This review, like its 1987 predecessor, addresses response of a discrete, time-invariant, linear, multiple degree-of-freedom system which exhibits nonclassical damping, including active damping. Unlike a classically damped system, the modes are coupled (or complex). In the intervening decade, stability issues involving nonclassical damping have received attention in applications such as high speed mechanisms, active structural control, vehicle dynamics, and seismic isolation of ground structures. Much of the recent literature has concerned approximate modal decoupling. There have also been contributions to the accurate calculation of the coupled modes, to general stability issues such as gyroscopic stabilization, and to eigenvalue/response bounds. The present article is intended both as a survey of recent literature and as a brief exposition of selected contributions of a general nature.
Piperaquine Pharmacodynamics and Parasite Viability in a Murine Malaria Model
Authors: Moore Brioni R. , Ilett Kenneth F. , Page-Sharp Madhu , Jago Jeffrey D. , Batty Kevin T.
Published: April 2009

Piperaquine (PQ) is an important partner drug in antimalarial combination treatments, but the long half-life of PQ raises concerns about drug resistance. Our aim was to investigate the extended antimalarial effect of PQ in a study of drug efficacy, reinoculation outcomes, and parasite viability after the administration of a single dose of PQ in the murine malaria model. Initially, male Swiss mice were inoculated with
Plasmodium berghei
and at 64 h after parasite inoculation were given PQ phosphate at 90 mg/kg of body weight intraperitoneally. Parasite viability, drug efficacy, reinoculation responses, and parasite resistance were determined at 25, 40, 60, 90, and 130 days after drug administration. At each time point, six mice were reinoculated with 10
7
P. berghei
parasites and blood was harvested from another four mice for viability passage into naïve mice (
n
= 5 for each blood sample) and from another two mice for determination of the plasma PQ concentration. The efficacy study demonstrated that the residual PQ concentrations did not suppress the infection after 25 days. Viable parasites were present up to 90 days after PQ dosing, although only 50% and 25% of the passaged parasites remained viable at 60 and 90 days postdosing, respectively. Viable parasites passaged into the naïve hosts were generally resistant to PQ when they were exposed to the drug for a second time. PQ was found to have a substantial antimalarial effect in this model, and the effect appears to be sufficient for a host immunological response to be established, resulting in the long-term survival of
P. berghei
-infected mice.
In Vitro Activities of Echinocandins againstCandida kruseiDetermined by Three Methods: MIC and Minimal Fungicidal Concentration Measurements and Time-Kill Studies
Authors: Cantón Emilia , Pemán Javier , Valentín Amparo , Espinel-Ingroff Ana , Gobernado Miguel
Published: April 2009

We evaluated the in vitro activities of anidulafungin, micafungin, and caspofungin againstCandida kruseiby determining MIC and minimum fungicidal concentration (MFC) measurements and by the time-kill method. The geometric mean (GM)-MIC/GM-MFC values were 0.1/0.34, 0.25/0.44, and 1/2.29, respectively. The mean times to reach 99.9% growth reduction were 19.1 ± 18.2 h (mean ± standard deviation) for 2 mg/liter anidulafungin, 37.4 ± 8.8 h for 2 mg/liter caspofungin, and 30.7 ± 12.2 h for 1 mg/liter micafungin. Anidulafungin exhibited the highest time-kill rate, followed by micafungin. The three echinocandins showed fungicidal activity at concentrations reached in serum.
Simultaneous Determination of Voriconazole and Posaconazole Concentrations in Human Plasma by High-Performance Liquid Chromatography
Authors: Kahle Kathrin , Langmann Peter , Schirmer Diana , Lenker Ulrike , Keller Daniela , Helle Annegret , Klinker Hartwig , Heinz Werner J.
Published: April 2009

A simple, sensitive, and selective high-performance liquid chromatographic method for the simultaneous determination of voriconazole and posaconazole concentrations in human plasma was developed and validated. Quantitative recovery following liquid-liquid extraction with diethyl ether was achieved. Linearity ranged from 0.10 to 20.0 μg/ml for voriconazole and from 0.05 to 10.0 μg/ml for posaconazole. The intra- and interday coefficients of variation were less than 8.5%, and the lower limits of quantitation were <0.05 μg/ml.
Genetic and Biochemical Characterization of the First Extended-Spectrum CARB-Type ß-Lactamase, RTG-4, from
Acinetobacter baumannii
Authors: Potron Anaïs , Poirel Laurent , Croizé Jacques , Chanteperdrix Vanessa , Nordmann Patrice
Published: April 2009

Acinetobacter baumannii
isolate KAR was uncommonly more resistant to cefepime and cefpirome than to ceftazidime and cefotaxime. Cloning and expression of the β-lactamase gene content of this isolate into
Escherichia coli
TOP10 identified ß-lactamase RTG-4 (or CARB-10), which corresponds to the first reported extended-spectrum CARB-type enzyme. RTG-4 is a plasmid-encoded Ambler class A β-lactamase whose sequence differs by 4 amino acid substitutions from the narrow-spectrum β-lactamase RTG-3. RTG-4 hydrolyzes cefepime and cefpirome and weakly hydrolyzes ceftazidime due to the single Ser-to-Thr substitution at Ambler position 69. RTG-4 is less susceptible to inhibition by tazobactam and sulbactam than RTG-3. Expression of β-lactamase RTG-4 in a wild-type
A. baumannii
reference strain showed that it conferred resistance to cefepime and cefpirome. The genetic environment of the
bla
RTG-4
gene was made of a peculiar transposon located on a ca. 50-kb plasmid. IS
Aba9
, located upstream of
bla
RTG-4
, may be responsible for its acquisition by recognizing a secondary right inverted repeat sequence, thus acting by a one-ended transposition process.
Population Modeling and Monte Carlo Simulation Study of the Pharmacokinetics and Antituberculosis Pharmacodynamics of Rifampin in Lungs
Authors: Goutelle Sylvain , Bourguignon Laurent , Maire Pascal H. , Van Guilder Michael , Conte John E. , Jelliffe Roger W.
Published: April 2009

Little information exists on the pulmonary pharmacology of antituberculosis drugs. We used population pharmacokinetic modeling and Monte Carlo simulation to describe and explore the pulmonary pharmacokinetics and pharmacodynamics of rifampin (RIF; rifampicin). A population pharmacokinetic model that adequately described the plasma, epithelial lining fluid (ELF), and alveolar cell (AC) concentrations of RIF in a population of 34 human volunteers was made by use of the nonparametric adaptive grid (NPAG) algorithm. The estimated concentrations correlated well with the measured concentrations, and there was little bias and good precision. The results obtained with the NPAG algorithm were then imported into Matlab software to perform a 10,000-subject Monte Carlo simulation. The ability of RIF to suppress the development of drug resistance and to induce a sufficient bactericidal effect against
Mycobacterium tuberculosis
was evaluated by calculating the proportion of subjects achieving specific target values for the maximum concentration of drug (
C
max
)/MIC ratio and the area under the concentration-time curve from time zero to 24 h (AUC
0-24
)/MIC ratio, respectively. At the lowest MIC (0.01 mg/liter), after the administration of one 600-mg oral dose, the rates of target attainment for
C
max
/MIC (≥175) were 95% in ACs, 48.8% in plasma, and 35.9% in ELF. Under the same conditions, the target attainment results for the killing effect were 100% in plasma (AUC
0-24
/MIC ≥ 271) but only 54.5% in ELF (AUC
0-24
/MIC ≥ 665). The use of a 1,200-mg RIF dose was associated with better results for target attainment. The overall results suggest that the pulmonary concentrations obtained with the standard RIF dose are too low in most subjects. This work supports the need to evaluate higher doses of RIF for the treatment of patients with tuberculosis.