bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation and optimization of the mechanical properties of highly filled PVC/(wood flour) composites by using experimental design
Authors: Fasihi Mohammad , Garmabi Hamid
Published: May 2011

In this study, PVC/(wood flour) (WF) composites were prepared by using a counterrotating twin‐screw extruder, and the effects on the mechanical properties of concentration and particle size of the WF, type and amount of coupling agent, K value of PVC, feed rate of extruder, and die temperature were investigated. Optimization of various formulation parameters based on the Taguchi method demonstrated that the wood content and wood particle size were the most important parameters. Flexural modulus increased upon increasing WF loading up to 50 wt%. Also, flexural strength and modulus increased with particle size because of the higher aspect ratio and better quality of mixing. Use of coupling agents had a minor effect that was attributed to the moderately high polarity of PVC causing relatively good compatibility between WF particles and the PVC matrix. The optimum level of WF calculated by considering the contribution factor was 50 wt%. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers
Vibrational Spectra and Quantum Chemical Calculations of the Pure and Mixed Cluster Anions [SixGe4–x]4– and [GexSn4–x]4– (x = 0–4) in Compounds with Potassium and Cesium
Authors: Ormeci Alim , Aydemir Umut , Somer Mehmet
Published: May 2011

The Raman spectroscopic studies on samples with the starting compositions Cs4[Si2Ge2] and M4[Ge2Sn2] (M = K, Cs) verify unambiguously the presence of phases composed of the mixed cluster moieties [SixGe4–x]4– and [GexSn4–x]4– (x = 1–3) including the pure anions [E4]4– (E = Si, Ge, Sn). The assignment of the vibrational frequencies is supported by normal coordinate analysis (NCA). The results for the mixed cluster anions are discussed in context with their isoelectronic analogs PxAs4–x (x = 1–3) and SbP3. Using the characteristic breathing frequencies, one obtains for the ratio factor of the mixed moieties κ = ν([SixGe4–x]4–) / ν(PxAs4–x) = 0.79, which is in good agreement with the reported value of 0.77 for the pure cluster series [E4]4– (E = Si, Ge, Sn) and X4 (X = P, As, Sb). The experimental average force constants f(Si‐Ge) = 1.01 Ncm–1 and f(Ge‐Sn) = 0.77 Ncm–1 correspond to arithmetic mean of those obtained for the pure anions in the binaries M4E4 (M = K, Rb, Cs; E = Si, Ge, Sn). The phonon frequencies of binary M4E4 (M = K, Cs; E = Si, Ge, Sn) and ternary K4ExE′4–x (E, E′ = Si, Ge or Ge, Sn, E ≠ E′, x = 1, 2, 3) were calculated by using pseudopotential electronic structure method SIESTA. Excellent agreement between the calculated and experimental frequencies was obtained for the pure binaries. The theoretical results compare also well with experimental values for the mixed series [SixGe4–x]4–, whereas for the corresponding mixed Ge‐Sn species the differences between measured and calculated frequencies are greater than 10 %.
Incidental Gallbladder Cancer by the AFC‐GBC‐2009 Study Group
Authors: Fuks David , Regimbeau Jean Marc , Le Treut Yves‐Patrice , Bachellier Philippe , Raventos Artivas , Pruvot François‐René , Chiche Laurence , Farges Olivier
Published: May 2011

Background

Incidental gallbladder cancer (GBC) is frequently discovered on the specimen when cholecystectomy for a benign disease is performed. The objective of the present study was to assess the management of incidental GBC patients in a French registry.

Methods

Data on patients with GBC treated between 1998 and 2008 were retrospectively collated in a French, multicenter database.

Results

The registry contained 218 patients with incidental GBC (67 men and 151 women; median age = 64 years; age range = 31‐88). One hundred forty‐eight (68%) patients underwent re‐resection after a median time interval of 48 days (range = 2–245). The most common complete procedure (66% of cases) was 4b + 5 segmentectomy with lymphadenectomy but not bile duct resection. Port‐site excision was performed in 54 patients. The mortality and morbidity rates were 3 and 37%, respectively. Resection of the common bile duct (43%) increased postoperative complications (60 vs. 23%, p = 0.0001). Local residual tumor was found in 83 (56%) patients; it was significantly correlated with the T stage and influenced long‐term survival. R0 was obtained in 143 (97%) patients and port‐site invasion was histologically confirmed in one patient (1.8%). After a median follow‐up period of 34 months, the 1‐, 3‐, and 5‐year survival rates for the 148 patients with re‐resection were 76, 54, and 41%, respectively. Re‐resection significantly increased survival in patients with T2 (p = 0.0001) and T3 (p = 0.04) disease. Resection of the common bile duct increased neither R0 resection nor overall survival (p = 0.06).

Conclusion

This study validates the concept of re‐resection in T2 and T3 GBC. Bile duct resection increases postoperative morbidity but does not improve survival. There is currently a modification in the surgical management of incidental GBC, with minor liver resection and no common bile duct resection.
Unpacking the Blockers: Understanding Perceptions and Social Constraints of Health Communication in Hereditary Breast Ovarian Cancer (HBOC) Susceptibility Families
Authors: Peters June A. , Kenen Regina , Hoskins Lindsey M. , Koehly Laura M. , Graubard Barry , Loud Jennifer T. , Greene Mark H.
Published: May 2011

Family communication is essential for accurate cancer risk assessment and counseling; family blockers play a role in this communication process. This qualitative analysis of social exchanges is an extension of earlier work characterizing those who are perceived by study participants as health information gatherers, disseminators, and blockers within families with Hereditary Breast and Ovarian Cancer (HBOC) susceptibility. Eighty‐nine women, ages 23–56 years, enrolled in a Breast Imaging Study (BIS) and participated in a sub‐study utilizing a social assessment tool known as the Colored Ecological Genetic Relational Map (CEGRM). Purposive sampling ensured that participants varied according to numbers of participating family members e.g., ranging from 1 to 6. Eighty‐nine women from 42 families (1–8 relatives/family) participated. They collectively designated 65 blockers, both male and female. Situational factors, beliefs, attitudes and cultural traditions, privacy and protectiveness comprised perceived reasons for blocking intra‐family health communications. Longitudinal data collected over 4 years showed families where blocking behavior was universally recognized and stable over time, as well as other families where blocking was less consistent. Self‐blocking was observed among a significant minority of participating women. Blocking of health communications among family members with HBOC was variable, complex, and multifaceted. The reasons for blocking were heterogeneous; duration of the blocking appeared to depend on the reasons for blocking. Blocking often seemed to involve bi‐directional feedback loops, in keeping with Lepore's Social Constraints and Modulation Theory. Privacy and protectiveness predominated as explanations for long‐term blocking.
Willing Slaves?
Authors: Scott Andrew
Published: May 2011

Many people believe that industrial relations have been transformed. For some, current developments are the result of new human resource management techniques which have overcome adversarial workplace traditions. For others, old attitudes remain, their expression stifled by vigorous competition in product and labour markets. Willing Slaves? explores these competing claims. It shows that managers have come to question past approaches to employee relations. Nowadays they believe that 'winning workers' hearts and minds' is a crucial part of successful management. Equally, however, managers have not yet found ways to make their new ideas work well. Workers continue to place little trust in management, inefficient working practices persist, and attempts to build a 'new industrial relations' have fallen short of the mark. Willing Slaves? concludes by arguing that the best way forward is for organisations to commit themselves to long term labour relations policies which enable workers to participate in management decision-making.
A Descriptive Catalogue of the Manuscripts in the Fitzwilliam Museum
Authors: James Montague Rhodes
Published: May 2011

M. R. James (1862–1936) is probably best remembered as a writer of chilling ghost stories, but he was an outstanding scholar of medieval literature and palaeography, who served both as Provost of King's College, Cambridge, and as Director of the Fitzwilliam Museum, and many of his stories reflect his academic background. His detailed descriptive catalogues of manuscripts owned by colleges, cathedrals and museums are still of value to scholars today. This volume contains James's catalogue of the manuscript holdings of the Fitzwilliam Museum, and will be welcomed by librarians and researchers alike.
Diary of William Hedges, Esq. (Afterwards Sir William Hedges), During his Agency in Bengal, as well as on His Voyage Out and Return Overland (1681–1687)
Authors: Hedges William
Published: May 2011

The publications of the Hakluyt Society (founded in 1846) made available edited (and sometimes translated) early accounts of exploration. The first series, which ran from 1847 to 1899, consists of 100 books containing published or previously unpublished works by authors from Christopher Columbus to Sir Francis Drake, and covering voyages to the New World, to China and Japan, to Russia and to Africa and India. Three volumes, published in 1887, are devoted to the diary of William Hedges (1632–1701) who in 1681 became the first Agent of the East India Company at its new base in Bengal. The first volume contains a transcription of the diary itself; Volume 2 contains a collection of documents relevant to Hedges' time in India; and Volume 3 is a documentary history of Thomas Pitt, grandfather of Pitt the Elder and Governor of Fort St George, who appears frequently in Hedges' diary.
The Works of John Ruskin
Authors: Ruskin John
Published: May 2011

The influence of John Ruskin (1819–1900), both on his own time and on artistic and social developments in the twentieth century, cannot be over-stated. He changed Victorian perceptions of art, and was the main influence behind 'Gothic revival' architecture. As a social critic, he argued for the improvement of the condition of the poor, and against the increasing mechanisation of work in factories, which he believed was dull and soul-destroying. The thirty-nine volumes of the Library Edition of his works, published between 1903 and 1912, are themselves a remarkable achievement, in which his books and essays - almost all highly illustrated - are given a biographical and critical context in extended introductory essays and in the 'Minor Ruskiniana' - extracts from letters, articles and reminiscences both by and about Ruskin. This thirty-seventh volume contains Volume 2 of Ruskin's letters, covering the years 1870–1889.
Suffolk and Norfolk
Authors: James Montague Rhodes
Published: May 2011

M. R. James (1862–1936) is probably best remembered as a writer of chilling ghost stories, but he was an outstanding scholar of medieval literature and palaeography, who served both as Provost of King's College, Cambridge, and as Director of the Fitzwilliam Museum, and many of his stories reflect his academic background. First published in 1930, this volume contains a guide to many historical places of interest in the counties of Suffolk and Norfolk. James concentrates mainly on the medieval history of these counties, weaving fascinating details of personalities and daily life with surviving examples of churches, monasteries and manors. In this tour around the two counties, the history of rich monastic foundations such as Bury St Edmunds and Norwich is discussed together with lesser-known historical sites in a clearly written and richly illustrated volume, which remains a valuable source for medieval scholars and historians.
Perceived and objective measures of the food store environment and the association with weight and diet among low-income women in North Carolina
Authors: Gustafson Alison A , Sharkey Joseph , Samuel-Hodge Carmen D , Jones-Smith Jesse , Folds Mary Cordon , Cai Jianwen , Ammerman Alice S
Published: May 2011

Objective

The present study aimed to highlight the similarities and differences between perceived and objective measures of the food store environment among low-income women and the association with diet and weight.

Design

Cross-sectional analysis of food store environment. Store level was characterized by: (i) the availability of healthy foods in stores where participants shop, using food store audits (objective); and (ii) summary scores of self-reported perception of availability of healthy foods in stores (perceived). Neighbourhood level was characterized by: (i) the number and type of food stores within the census tract (objective); and (2) summary scores of self-reported perception of availability of healthy foods (perceived).

Setting

Six counties in North Carolina.

Subjects

One hundred and eighty-six low-income women.

Results

Individuals who lived in census tracts with a convenience store and a supercentre had higher odds of perceiving their neighbourhood high in availability of healthy foods (OR = 6·87 (95 % CI 2·61, 18·01)) than individuals with no store. Overall, as the number of healthy foods available in the store decreased, the probability of perceiving that store high in availability of healthy foods increased. Individuals with a supercentre in their census tract weighed more (2·40 (95 % CI 0·66, 4·15) kg/m2) than individuals without one. At the same time, those who lived in a census tract with a supercentre and a convenience store consumed fewer servings of fruits and vegetables (−1·22 (95 % CI −2·40, −0·04)).

Conclusions

The study contributes to a growing body of research aiming to understand how the food store environment is associated with weight and diet.
A Path-Following Control Algorithm for Manufacturing Systems Based Upon the Decomposed Contour Error
Authors: Ho Hsin-Chiang , Yen Jia-Yush
Published: May 2011

We propose a new path following control algorithm. The algorithm decomposes the trajectory errors into tangential and normal components. The normal component minimizes the tracking error, while the tangential component maintains the desired speed. Experimental results using an X-Y table indicate that the proposed method possesses satisfactory tracking characteristics. It resolves certain previously difficult to control problems.
Investigation Of Buoyancy Effects in Non-Isothermal Rotating Flows by Scaling Analysis and a Novel Similarity Model
Authors: Soong C. Y. , Chyuan C. H.
Published: May 2011

The objective of the present study is to investigate the buoyancy effects induced by various body forces in non-isothermal rotating fluids. The buoyancy effects stemmed from the gravity, the centrifugal and Coriolis forces generated by system rotation, and the curvilinear motion of the fluids are all taken into account. Mixed convection between two disks rotating at different rates is employed as the physical model. The present work is the first study for detailed investigation of the various buoyancy forces in the class of non-isothermal flows. Complete system of axially-symmetric thermal flow model with assumption of Boussinesq fluids is formulated. By a scaling analysis and the solutions of a novel similarity model developed in this work, the relative importance of the buoyancy effects induced by various body forces is explored. The present work discloses the significance of the rotation-induced buoyancy effects under various conditions and is useful in understanding the mechanisms as well as modeling the mixed convection heat transfer in the class of rotating thermal flows.
Linear Structure Vibration Control Using MFT and Robust Kalman-Filter-Based OMFC Method
Authors: Chen Shinn-Horng , Chou Jyh-Horng
Published: May 2011

This paper proposes a robust Kalman-filter-based optimal model-following control (OMFC) methodology for actively suppressing the vibration of the mechanical structure system, which is modeled by the modal force technique (MFT) and subjects to both disturbance/noise uncertainties and linear structured time-varying parameter perturbations. The proposed method can not only avoid the problem of how to choose appropriate weighting matrices in the quadratic cost function of the linear quadratic Gaussian (LQG) control but also make the controlled closed-loop system to have desired system response characteristics. Besides, this paper also presents a robust stability criterion to guarantee that the designed controller can keep the controlled mechanical structure system from the possibility of time-varying-parameter-perturbation-induced instability. An example of L-shaped cantilever beam structure system is employed to demonstrate the application of the proposed method and the use of the robust stability criterion. Numerical simulation is performed to evaluate the improvement of the vibration response.
Doubly Diffusive Convection Due to a Point Source at Various Depths in a Stratified Fluid
Authors: Kong Chin-Hwa , Liu Chi-Min , Yang Ray-Yeng
Published: May 2011

The problem of a stable stratified fluid heated by a point source of heat at various depths is treated in this paper. A hot plume is formed with a series of layer around and above it. Quantitative estimates for the criterion of onset of doubly diffusive instability are obtained in this work. The linear differential system governing stability is then solved. The results show that the stationary onset of this doubly diffusive problem caused by a point source may be led to a similar form of small-gap Taylor- Couette problem.
Wind-Structure Interaction by the Numerical Simulation
Authors: Young D. L. , Chang J. T.
Published: May 2011

A new computational procedure is developed to solve the external field problems of the incompressible viscous flows. The method is able to solve the infinite boundary value problems by extracting the boundary effects coming from the finite computational domain. The present method is based on the projection method of the Navier-Stokes equations. We use three-step explicit finite element method to solve the momentum equation of the flow motion. The external field solver of the boundary element is used to treat the pressure Poisson equation. The arbitrary Lagrangian-Eulerian method is employed to deal with the moving boundary, such as wind-structure interaction problems. For illustration of the present numerical code, a vortex-induced cross-flow oscillations of a circular cylinder mounted on an elastic dashpot-spring system is considered. The phenomena of the beat, lock-in, and resonance are revealed in the Reynolds number range between 100 and 110, which are much narrower than the previous studies.
Pressure Fluctuations in Rectangular Cavity Flows
Authors: Chung Kung-Ming
Published: May 2011

Experiments are performed to study the unsteadiness of rectangular cavity flows at Mach 0.325, 0.620 and 0.818. Typical characteristics of mean surface pressure distributions show a slight pressure variation near the front face, a local peak surface pressure ahead of the rear corner and a low pressure at immediate downstream of the cavity. Larger peak pressure and pressure variation near the cavity rear face are observed as the length-to-depth ratio increases. Surface pressure fluctuation distribution shows an increase toward the cavity rear face and reaches a peak value. At further downstream locations, the level of surface pressure fluctuation approaches the value of incoming flow. The amplitude of peak surface pressure fluctuation is associated with length-to-depth ratio and reaches the maximum at length-to-depth ratio of 8.60. This is considered due to intermittent switching between open- and closed-cavity flows. Higher moments of surface pressure signal at immediate downstream of the cavity show a similar trend. More negative skewness coefficient and larger deviation of flatness coefficient indicate the presence of more large negative events, which is mainly corresponding to mass removal process (breath-out phase). This unsteady mass flow is more pronounced at higher Mach number.
Use of Simple Model to Predict the Forced Vibration Responses of Hualien Model Structure
Authors: Chen Cheng-Hsing , Yang Shuh-Hua
Published: May 2011

This paper uses a simple model, the lumped single-degree-of-freedom system on rigid mat foundation, to investigate the effects of soil-structure interaction on the dynamic response of a soil-structure system. Based on that, the key parameters affecting the natural frequency of a soil-structure system can be easily identified and be used to assess the effects of soil-structure interaction. Accordingly, it was used to simulate the dynamic response of the forced vibration tests conducted at Hualien, Taiwan. Results obtained show that the simple model can predict the field responses very satisfactorily.
Three-Dimensional Stokes Flow Solution Using Combined Boundary Element and Finite Element Methods
Authors: Young D.L. , Liu Y.H. , Eldho T.I.
Published: May 2011

This paper describes a model using boundary element and finite element methods for the solution of three-dimensional incompressible viscous flows in slow motion, using velocity-vorticity variables. The method involves the solution of diffusion-advection type vorticity equations for vorticity whose solenoidal vorticity components are obtained by solving a Poisson equation involving the velocity and vorticity components. The Poisson equations are solved using boundary elements and the vorticity diffusion type equations are solved using finite elements and both are combined. Here the results of Stokes flow with very low Reynolds number, in a typical cavity flow are presented and compared with other model results. The combined BEM-FEM model has been found to be efficient and satisfactory.
Analysis of the Mechanic Behavior and Rutting of Asphalt Concrete Using a Sand Model
Authors: Liu Ming-Lou
Published: May 2011

The stress-strain relationship of the sand and asphalt concrete materials is one of the most important research subjects in the past, and many conctitutive laws for these materials have been proposed in the last two decades. In this study, the Vermeer plasticity model is modified and used to predict the behavior of the sand and asphalt concrete materials under different stress path conditions. The results show that the predictions and test results agree well under different stress path conditions. However, the orignal Vermeer model can not predict the stress-strain behavior of the asphalt concrete. Finally, the modified Vermeer plasticity model is incorporated with the pavement rutting model to predict the rut depth of pavement structure under traffic loadings.
Developing a Mini-Impact System for Measuring Silicon Wafer's Elastodynamic Response
Authors: Jenq S. T. , Leu T. S. , Su Y. G. , Lee J. S. , Hwang G. C.
Published: May 2011

The purpose of this work is to study the dynamic mechanical response of silicon wafer subjected to low-velocity impact loading. Transient finite element analysis was utilized to obtain the numerical simulated result and was used to check against the experimental findings. Good relationship between each other was observed. A pair of polysilicon microsensors manufactured by the micro-fabrication technique was directly fabricated on the surface of silicon wafer so as to detect the impact induced dynamic strain. A series of low-velocity impact tests utilizing the home-made drop-weight mini-tower tester was conducted. These test results were used to examine the accuracy and adequacy of the current micro strain sensors for stress wave propagation measurements. It is concluded that the difference between the present measured wave speed and the one-dimensional longitudinal wave speed under conditions of plane strain were determined to be within 5.6% for the present low-speed impact problem. A maximum of 10.9% deviation between the test determined elastic modulus and a reference value (16) of 130 GPa was found based on a series of impact test results. In addition, a difference of 2% error was reported when we compared the test detected peak stress value after impact initiated (before wave is reflected from the boundary) and the corresponding numerical simulated response.
Comparisons of Joint Kinetics in the Lower Extremity Between Stair Ascent and Descent
Authors: Lin H.-C. , Lu T.-W. , Hsu H.-C.
Published: May 2011

Stair locomotion has been used in the rehabilitation of the lower extremity as a motor performance test and multi-joint exercise. Controversies exist regarding joint loads during stair locomotion. The purposes of the study were to investigate the three-dimensional kinetics of the lower limb joints during stair locomotion, and to compare them with those during level walking. Ten normal young adults walked, and ascended and descended stairs in a gait laboratory while kinematic and kinetic data were collected and analyzed. The results showed that the intersegmental resultant forces at the joints during the activities were generally similar in pattern but the force magnitudes, moments and angular impulses were significantly different. The general impression that the loads in the lower limb were larger during stair descent than stair ascent only holds for certain kinetic variables. Most of the peak joint moments and angular impulses over the entire stance phase were bigger during stair ascent than descent. The study provides a complete knowledge of the three-dimensional loading patterns at and dynamic functions of the lower limb joints during level walking and stair locomotion. It will be helpful for the planning and evaluation of treatment programs for patients with neuromusculoskeletal pathologies in the lower extremities.
Exact Solutions for a Fluid-Saturated Porous Medium with Heat and Mass Transfer
Authors: Liu I-C.
Published: May 2011

An analysis is performed to the study of the momentum, heat and mass transfer of a viscous fluid-saturated porous medium past an impermeable, non-isothermal stretching sheet with internal heat generation or absorption and chemical reaction. The governing partial differential equations are converted into ordinary differential equations by means of a similarity transformation. Exact solutions of velocity components together with the pressure distribution, which can not be found in the boundary layer theory, are obtained analytically; in addition, the temperature and concentration functions are given in terms of confluent hypergeometric functions. The velocity, temperature (concentration) profiles and thermal characteristics at the sheet for relevant parameters are plotted, tabulated and discussed.
Novel EHD-Pump Driven Micro Mixers
Authors: Leu T.-S. , Ma F.-C.
Published: May 2011

Novel electrohydrodynamic (EHD) pump driven micro mixers are fabricated to study fluidic mixing in micro channels experimentally. Microscopic flow visualization experiments are presented to visualize microscale mixing in micro mixers. Mixing is achieved in a laminar flow by perturbing the main flow with EHD pumps in a micro channel. EHD pumps operate in a way to form cross-stream mixing mechanism by using either dc voltage or traveling wave signals. Experimental results show transverse or vortical cross-stream flows are generated within hundreds microns distance in the micro mixers, thereby increasing mixing.
Simulating Runoff Using the Method of Characteristics with Unsteady Rainfall Events
Authors: Wu C.-M. , Chen S.-C.
Published: May 2011

This investigation presents the solution of kinematic wave equations for overland flow, in which the lateral term is determined from unsteady rainfall and the infiltration φ index model [1], in which the rate of abstractions is constant, yielding an excess rainfall hyetograph with a total depth that equals the depth of direct runoff over the watershed. Lateral inflow is inferred by the unit step function to represent an unsteady rainfall event; the solution uses the method of characteristics. Part of the discharge hydrograph that satisfies the boundary condition is semi-analytically solved, by a reduced, simple procedure, which does not require the use of numerical method such as finite difference. The analysis presented herein this investigation deals with both rising and falling stages. Example calculations, water surface profiles, and discharge hydrographs are also presented.
Variational Stability Analysis of Cohesive Slope by Applying Boundary Integral Equation Method
Authors: Wu L.-Y. , Tsai Y.-F.
Published: May 2011

Applying the concept of minimum potential energy and the variational method proposed in this paper, one can derive the governing equation and transversality conditions for the critical slip surface of a cohesive land slope described by simplified Janbu's model where both horizontal and vertical inter-slice forces are neglected. The governing equation, transversality conditions and boundary conditions were solved by the boundary integral equation method, which is a one dimensional BIEM, so that the critical slip surface and its associated minimal factor of safety can be determined effectively. By comparison of the results gotten from the boundary integral equation method and other numerical methods, it can be concluded, that, for some simplified cases, by using the boundary integral equation method on slope stability analysis of a cohesive land slope, a more reasonable result can be obtained.
Acoustic Scattering by a Fluid-Encapsulating Spherical Viscoelastic Membrane Including Thermoviscous Effects
Authors: Hasheminejad Seyyed M.
Published: May 2011

This study provides a general analysis for scattering of a planar monochromatic compressional sound wave by a fluid-filled viscoelastic spherical membrane immersed in an unbounded viscous heat-conducting compressible fluid. The thermoviscous effects in the fluid are incorporated by application of a thin boundary layer model. The dynamic viscoelastic properties of the spherical membrane are rigorously taken into account in the solution of the acoustic-scattering problem. Havriliak-Negami model for viscoelastic material behaviour along with the appropriate wave-harmonic field expansions and the pertinent boundary conditions are employed to develop a closed-form solution in form of infinite series. Subsequently, the basic acoustic quantities, such as the scattered far-field pressure directivity pattern, and the scattering cross section are evaluated for given sets of viscoelastic material properties. Numerical results clearly indicate that, in addition to the traditional fluid thermoviscosity-related mechanisms, dynamic viscoelastic properties of the obstacle can be of significance in sound scattering. The presented analysis is of practical interest in development of contrast agents for echocardiographic research with potential clinical applications.
A Steady Creep Theory of High Lead Pb/Sn Solder with Creep-Parameters Maps
Authors: Lee C. F. , Wang J. J. , Chung W. K.
Published: May 2011

In this paper, Valanis' steady creep theory with four creep parameters was derived from a liaison of the theory of deformation kinetics with internal isotropy and the theory of irreversible thermodynamics of continuous media with only one internal state variable.

According to the theory, steady creep rates under simple shear and simple tensile conditions are related and allow one to construct creep-parameters maps of high lead Pb/Sn solders (from 90% to 100% Pb). When testing temperatures are higher than solder's solvus temperature, microstructural transformation from lamellae α + β phase to solid solution α phase in the bulk specimens are considered in the construction of maps. Applications of maps in the 97.5Pb/2.5Sn solder joints creep tests need minor modifications due to dispersive precipitation of tin particles in lead matrix. As a result, the maps may provide estimated steady creep rates for the usage of finite elements analysis in the microsystem or electronic packaging analysis.
Turbulent Film Condensation on a Nonisothermal Horizontal Tube
Authors: Lin Yan-Ting , Yang Sheng-An
Published: May 2011

A simple model has been developed for the study of turbulent film condensation from downward flowing vapors onto a horizontal circular tube with variable wall temperature. The interfacial shear at the vapor condensate film is evaluated with the help of Colburn analogy. The condensate film flow and local/or mean heat transfer characteristics from a horizontal tube with non-uniform temperature variation under the effect of Froude number, sub-cooling parameter and system pressure parameter has been conducted. Although the non-uniform wall temperature variation has an appreciable influence on the local film flow and heat transfer; however, the dependence of mean heat transfer on the non-uniform wall temperature variation is almost negligible.
Analysis for Forced Vibration Test on Proto-Type Pile Foundation in Tsip
Authors: Ko Yung-Yen , Chu Huei-Chun , Chen Cheng-Hsing
Published: May 2011

A series of forced vibration tests were conducted on a proto-type pile foundation which is built in the Tainan Science-Based Industrial Park and is modeled on the foundation type of Taiwan High Speed Rail. The test method, analysis procedure and results of test are briefly introduced in this paper. Besides, a finite element method by using the computer program ABAQUS is used to simulate the test. Results obtained are in good agreement with the results of in-situ test, and both are helpful for understanding the characteristics of the ground responses of the site and for identification of the soil-structure interaction of Taiwan High Speed Rail foundation system.
Effective Lengths of Tensile and Torsional Specimens of Piezoelectric Materials
Authors: Tarn J.-Q. , Chang H.-H.
Published: May 2011

The effective length of a piezoelectric cylindrical specimen in strain measurements is determined by considering the stress decay in a cylindrically anisotropic, circular cylinders of piezoelectric materials subjected to 2D surface tractions and prescribed end loads. On the basis of the state space formalism, the problem is studied by means of matrix algebra. The significance of the end effects is evaluated through a characteristic decay length. The study enables us to assess Saint-Venant's principle as applied to piezoelectricity in general and to determine the effective lengths of tensile and torsional specimens of piezoelectric materials in particular.
Simulation of Flow Past a Square Cylinder by Parallel Lattice Boltzmann Method using Multi-Relaxation-Time Scheme
Authors: Wu J.-S. , Shao Y.-L.
Published: May 2011

The flows past a square cylinder in a channel are simulated using the multi-relaxation-time (MRT) model in the parallel lattice Boltzmann BGK method (LBGK). Reynolds numbers of the flow are in the range of 100 ∼ 1,850 with blockage ratio, 1/6, of cylinder height to channel height, in which the single-relaxation-time (SRT) scheme is not able to converge at higher Reynolds numbers. Computed results are compared with those obtained using the SRT scheme where it can converge. In addition, computed Strouhal numbers compare reasonably well with the numerical results of Davis (1984).
Analysis of Stress Singularities at Bi-Material Corners in Reddy's Theory of Plate Bending
Authors: Huang C. S.
Published: May 2011

The order of stress singularity at a sharp corner of a plate needs to be known before a numerical approach can be taken to determine accurately the stress distribution of a plate with irregular geometry (such as a V-notch) under loading. This work analyzes the order of the stress singularity at a bi-material corner of a thick plate under bending, based on Reddy's third-order shear deformation plate theory. An eigenfunction expansion technique is used to derive the asymptotic displacement field in the vicinity of the sharp corner by solving the equilibrium equations in terms of displacement functions. This paper explicitly shows the first known characteristic equations for determining the order of the stress singularity at the interface corner of a bonded dissimilar isotropic plate. Moreover, the numerical results are given in graphic form for the order of stress singularity at the interface corner in bonded dissimilar isotropic plates and at the vertex of a bi-material wedge with free radial edges. The results presented herein fill some of the gaps in the literature
Theory of Endochronic Cyclic Viscoplasticity of Eutectic Tin/Lead Solder Alloy
Authors: Lee C. F. , Shieh T. J.
Published: May 2011

In this paper, a theory of Endochronic cyclic viscoplasticity of eutectic Tin/Lead (60Sn/40Pb) solder alloy under cyclically thermomechanical strain histories had been established. Under the conditions of isotropic and inelastically incompressible small deformation, the constitutive equation of deviatoric behavior was expressed as:

here and the strain rate dependent intrinsic time scale and . Employing the experimental cyclic shear stress-strain curves of various testing temperature and frequency, all temp. dependent material parameters and ; and the temp.-freq. dependent material function were determined for temp. between 213K and 423K and freq. between 0.3Hz and 0.01Hz. Predicative capability of the theory were then challenged by a set of experiments with complicate strain history such as (i) Fast in tension/Slow in compression constant strain amplitude cyclic tests (ii) Slow-Fast-Slow constant amplitude cyclic tests. Through the excellent computational results, the present theory demonstrated that it can, not only play a vital role in the area of electronic solder mechanics, but also meet the needs of reliability analysis and life assessment in the electronic/photoelectronic packagings.
Rivulet Instability with Effect of Coriolis Force
Authors: Cho H.-C. , Chou F.-C.
Published: May 2011

The effect of Coriolis force on the rivulet (fingering) instability, the onset of rivulet phenomena during spin coating, is investigated by flow visualization experiments incorporating with dimensional analysis. This study demonstrates that the Coriolis force will affect significantly the critical radius of rivulet instability and the deflection angle of instability rivulet. For the cases of low Bond number, the effect of Coriolis force is a stabilizing factor, and the dimensionless critical radius increases slightly with increasing rotational Reynolds number Reω. In the case of high Bond number, the effect of Coriolis force becomes a destabilizing factor while Reω < 1, and a characteristic length is found by balancing the viscous force with the surface tension. For Reω > 1, the radial Corilois force, which is always pointing inward, plays a stabilizing role with magnitude Reω2.
Forces Transmitted in the Knee Joint During Stair Ascent and Descent
Authors: Lu T.-W. , Lu C.-H.
Published: May 2011

The normal function of the knee relies upon a complicated and delicate mechanical interaction between the force-bearing structures, including muscles, ligaments and articular surfaces. Injury or damage to any of these structures will lead to the degradation or loss of joint function. Stair locomotion is one of the most common forms of motion in daily living. The purposes of the study were to analyze forces transmitted by the force-bearing structures of the knee during normal stair ascent and descent and to evaluate their mechanical differences. Compared to stair descent, higher peak patellar tendon forces, peak flexor forces, posterior cruciate ligament (PCL) forces and contact forces were required during stair ascent. In contrast, the anterior cruciate ligament (ACL) trended to bear higher forces during stair descent. It is suggested that one should be cautious in the use of stair ascent and descent as a rehabilitation exercise for patients with injuries or diseases of the cruciate ligaments and articular surfaces. The results of the study will be helpful for the understanding of the normal mechanics of the knee during stair locomotion, contributing to the design and evaluation of rehabilitation programs for patients with knee problems such as ACL injury and osteoarthritis.
A Study on Mixing Efficiency in a Two-Channel Circular Micromixer
Authors: Chang M. , Hu Y.-H. , Chau S.-W. , Lin K.-H.
Published: May 2011

The mixing behavior of a two-channel micromixer with a circular mixing chamber at four different chamber depths and six different flow rates had been investigated. Experiments were implemented with the mixings of two fluids. An image inspection method using the variance of the image gray level contrast as the measurement parameter to determine the mixing efficiency distribution in these mixers. The steady, three-dimensional and laminar flow fields inside the micromixers were also simulated numerically with a finite volume discretization. Through the numerical integration over the chamber depth, the three-dimensional numerical prediction could be compressed into a two-dimensional result, which could be directly used to compare with the experimental measurements. Experimental results show that the measured mixing efficiency is raised with the increase of chamber depth. The numerical prediction of mixing efficiency agreed qualitatively with those obtained from the experimental measurements, while the ratio of the depth to diameter of the mixing chamber is big enough to eliminate the viscosity effect.
Unsteady Analysis of Microvalves With No Moving Parts
Authors: Wang C.-T. , Leu T.-S. , Sun J.-M.
Published: May 2011

No-moving-parts valves (NMPV) pumps produce the net volume flow due to the difference of pressure resistances between forward and reverse flow of a microchannel structure. NMPV has been developed by a number of research groups. However, most of NMPV in these studies are designed and based on steady state flow conditions. Little data is available regarding the NMPV in unsteady flow conditions. In this study, the performances of NMPV under both steady and unsteady flow conditions are investigated numerically. The NMPV used in this study is a diffuser-type microchannel with diffuser angle of 20° because of its outstanding production of net volume flow. By a series of numerical simulations, some useful results would be addressed for the performance of NMPV micropumps. First, Reynolds number confirmed by steady analysis should be greater than 10 (Re > 10) for the NMPV pumps to be more effective. Second, an optimal Strouhal number with maximum net volume flow rate is found at St = 0.013 for the unsteady flow condition. In addition, the relation between the driving pressure amplitude and net volume flow rate with a linear behavior found was helpful to the performance of the micropump system. According to these findings, it was easy for users to operate and design of NMPV micropumps.
Injection Molding Simulation of 3D Stacked-Chip Assembly Packaging with Different Entrances
Authors: Lin C.-M. , Lin T.-C. , Chu H.-M. , Chen Y.-L.
Published: May 2011

This paper adopts a three-dimensional (3D) finite element method to simulate the injection molding of organic 3D stacked-chip assemblies. The geometry model of the assembly is simplified to a five-layered structure of stacked-chips with no solder bumps. The injection molding process incorporates 3D stacked-chip packaging and encapsulation techniques, and comprises primarily of multi-layer cavity-filling and reactive-thermosetting curing processes. The current investigation considers the effects of specifying different entrances on the resultant flow fronts, air-traps, and weld-lines. In general, the present results confirm the value of performing numerical simulations of the 3D stacked-chip packaging process to support the injection molding CAE approaches which are commonly applied nowadays to improve the packaging assembly design and to facilitate the rapid set up of mass-production conditions. The simulation results indicate that the best packaging results are obtained when the melt is introduced either at the center of the periphery side of the stacked-chip modulus or at its corner.
Finite Element Analysis of Screw-Plate Systems for Fixation of Parasymphyseal Fractures of the Mandible
Authors: Lovald Scott T. , Khraishi Tariq , Wood John , Wagner Jon , Baack Bret , Kelly James
Published: May 2011

Finite Element Modeling was used to compare the efficacy of common screw-plate configurations used for fixation of parasymphyseal fractures of the mandible. Measures of Von Mises stress on the screw bone interface, as well as principal strain in the reduced fracture region, were used in this comparison. This study also explored differences between orthotropic and isotropic modeling practices and compared the effect of mastication forces on both the fractured and intact halves of the mandible. The results of this analysis showed no major differences between configurations from a mechanistic point of view. This suggests that the use of any of the studied screw-plate configurations will not increase chances for post-operative complications. Furthermore, little difference is seen between analyses with either orthotropic or isotropic material properties. The inclusion of orthotropic properties can thus be avoided in future studies with similar boundary and plating conditions. Mastication ipsilateral to the fracture increases Von Mises stress 2 to 4 times, and should be avoided during early healing periods. These recommendations only apply to patients whose fractures mimic the finite-element model.
An Energy Transmitting Boundary for Semi-Infinite Structures
Authors: Chen S.-S. , Hsu W.-C.
Published: May 2011

A soil-structure system associated with a semi-infinite structure such as tunnel or pavement is usually investigated by finite element analysis. If the boundary of the finite element model selected is not far enough from the excitation source or does not have an appropriate energy-absorption mechanism, it may introduce a significant error induced by reflected waves. This study develops a structural transmitting boundary to absorb the transmitting energy at the boundary of the analytical model. The structure is divided into finite and semi-infinite regions. The stiffness of the semi-infinite region is established by the principle of virtual work and applied at the transmitting boundary. The comparisons of the structural displacements induced by vertical harmonic excitations show that the analytical model size can be significantly reduced, if the proposed transmitting boundary is used to simulate the semi-infinite structural region.
Dynamic Crack Propagation in Piezoelectric Materials Subjected to Dynamic Body Forces for Vacuum Boundary
Authors: Chen X.-H. , Ma C.-C. , Ing Y.-S.
Published: May 2011

The problem of a semi-infinite propagating crack in the piezoelectric material subjected to a dynamic anti-plane concentrated body force is investigated in the present study. It is assumed that between the growing crack surfaces there is a permeable vacuum free space, in which the electrostatic potential is nonzero. It is noted that this problem has characteristic lengths and a direct attempt towards solving this problem by transform and Wiener-Hopf techniques [1] is not applicable. This paper proposes a new fundamental solution for propagating crack in the piezoelectric material and the transient response of the propagating crack is determined by superposition of the fundamental solution in the Laplace transform domain. The fundamental solution represents the responses of applying exponentially distributed loadings in the Laplace transform domain on the propagating crack surface. Exact analytical transient solutions for the dynamic stress intensity factor and the dynamic electric displacement intensity factor are obtained by using the Cagniard-de Hoop method [2,3] of Laplace inversion and are expressed in explicit forms. Finally, numerical results based on analytical solutions are calculated and are discussed in detail.