bluuebunny/crossref_metadata_2025 huggingface dataset:
Review: Anti-Influenza Virus Drug Design: Sialidase Inhibitors
Authors: Dyason Jeffrey C. , von Itzstein Mark
Published: August 2002

This review will give an overview of the design process behind the development of sialidase inhibitors, which can be used as anti-influenza drugs. Two drugs (Relenza™ and Tamiflu™) are already available as prescription drugs and a third (BCX-1812) is currently undergoing third-phase clinical trials. Also, the use of molecular-modelling techniques in the understanding of the mechanism and the prediction of inhibition of this enzyme is reviewed.
Sphaerolobium macranthum (Leguminosae: Mirbelieae) complex revised
Authors: Butcher Ryonen , Chappill Jennifer A.
Published: August 2002

In this paper, the Sphaerolobium macranthum Meisn.
complex is revised and the following taxonomic conclusions made: the names
S. drummondii Turcz. and
S. pulchellum Meisn. are reinstated, the name
S. macranthum is correctly applied and a new species,
formerly recognised as S. macranthum var.
parviflorum Benth., is described as
S. validum R.Butcher. Illustrations, maps and full
descriptions of the taxa within this complex are provided and a partial key to
Sphaerolobium is presented.
Taxonomic revision of Hannafordia (Lasiopetaleae: Sterculiaceae (Malvaceae s.l.))
Authors: Wilkins C. F. , Chappill J. A.
Published: August 2002

Taxonomic revision of the endemic Australian genus
Hannafordia F.Muell. identified five taxa, including
three recognised species, a new subspecies
H. quadrivalvis F.Muell. subsp.
recurva C.F.Wilkins and a new subspecific combination
H. bissillii F.Muell. subsp.
latifolia (E.Pritzel) C.F.Wilkins. Taxonomic
descriptions, a key, distribution maps, illustrations, anatomical findings and
seed and seedling morphology are presented. A chromosome number of
n = 10 is the first published record for the
genus.
Fuel loading prediction models developed from aerial photographs of the Sangre de Cristo and Jemez mountains of New Mexico, USA
Authors: Scott Kelly , Oswald Brian , Farrish Kenneth , Unger Daniel
Published: August 2002

Fuel load prediction equations that made use of aerial photographs were
developed for Mixed Conifer, Ponderosa Pine
(Pinus ponderosa Dougl. ex Laws.) and
Pinyon–Juniper (Pinus edulis
Engelm.)–(Juniperus monosperma Engelm.) cover types
from one-time measurements made in the Santa Fe watershed (SFWS) located in
the Sangre de Cristo Mountains of northern New Mexico, and at Los Alamos
National Laboratory (LANL) located in the Jemez Mountains of northern New
Mexico. The results of the watershed data set were favorable and exhibited a
high degree of relative accuracy. The results from the LANL data set did not
share the same degree of accuracy, but rather exhibited a high degree of
error. Use of these or similar prediction equations may be limited to certain
regions and community types that exhibit similar regional characteristics such
as terrain, soil, and weather conditions. Applied use of the prediction
equations required less time than traditional fuel sampling performed onsite,
but suffered from a loss of accuracy. It is strongly suggested that additional
study of this method be undertaken to generate more accurate and reliable
equations. Hopefully, more accurate equations may augment existing fuel
sampling techniques and be put to practical use for fire planning purposes.
Riparian gravel banks of upland and lowland rivers in Victoria (south-east Australia): arthropod community structure and life-history patterns along a longitudinal gradient
Authors: Framenau Volker W. , Manderbach Randolf , Baehr Martin
Published: August 2002

Riparian sand and gravel banks are inhabited by a fauna that is well adapted
to varying river water levels and frequent inundation of the banks. Arthropods
found in these habitats were studied from November 1998 to January 1999 in the
upper and lower floodplains of the main rivers and tributaries in ten major
catchments in the Victorian Alps. Wolf spiders (Lycosidae, 68%) and
ground beetles (Carabidae, 7.8%) were the most abundant arthropods,
with densities averaging 14.6 ± 1.8 (s.e.) and 2.3 ± 0.4
individuals m–2 respectively. Species composition
and wolf spider densities changed substantially between upland and lowland
rivers. These differences correspond with changes in altitude, shading, and
gravel and gravel bank size. Comparison of our results with similar studies
conducted in temperate Northern Hemisphere floodplains showed significant
differences. Carabidae, not Lycosidae, are the dominant arthropod group in
Northern Hemisphere floodplains. Wolf spider densities are higher in upper
than lower reaches of rivers in the Victorian Alps, but do not change along
rivers in the Northern Hemisphere. In contrast, carabid beetles showed similar
densities between upland and lowland floodplains in Victoria, but increase in
density along rivers in the Northern Hemisphere. A second, monthly sampling
program on gravel banks along the Avon River (Gippsland) over a one-year
period in 1996 and 1997 provided information on the life histories of eight
common gravel-bank arthropods: Venatrix lapidosa,
V. arenaris, two undescribed
Artoria species (‘A’, ‘B’)
(Lycosidae), Eudalia macleayi,
Elaphropus ovensensis,
Perileptus constricticeps and an unidentified
Loxandrus species (‘B’) (Carabidae).
Artoria sp. A and sp. B are diplochronous. Despite its
smaller size, Artoria sp. B matured one month after
Artoria sp. A. Lower temperatures at upland streams and
rivers, the typical habitat for Artoria sp. B, may delay
its development in comparison with Artoria sp. A, which
is generally found further downstream. The life histories of both lycosid
spiders and carabid beetles, characterised by prolonged reproductive period
and short larval development, appear to have some adaptive value in regard to
the disturbance-prone environment.
A Simplified Model for Plain Woven Fabrics
Authors: Kollegal Manohar G. , Sridharan Srinivasan
Published: August 2002

A simplified model for studying the behavior of plain woven fabrics is presented. The model consists of two plate elements including a thin layer of matrix between them. Hierarchic shape functions are employed to characterize the initially curved profile of the yarns and the displacements of the plate elements. The plate model is used in conjunction with a simple micro-model which accounts for the material nonlinear response and damage of the yams. The behavior of plain woven fabrics under inplane tension, compression and inplane shear is examined. The plate-micro model combination is shown to be able to predict the important features of plain woven fabric response adequately. Predictions of the strength of plain woven fabrics using the plate model are compared with 3-D finite element analysis (FEA) results and currently available experimental/analytical results.
Inhibition of Bioprosthesis Calcification Due to Synergistic Effect of Fe/Mg Ions to Polyethylene Glycol Grafted Bovine Pericardium
Authors: Vasudev Sindhu C. , Chandy Thomas , Mohanty Mira , R. Umasankar P. , Sharma Chandra P.
Published: August 2002

Calcification has limited the durability of bioprosthetic heart valves fabricated from glutaraldehyde pretreated porcine aortic valves or bovine pericardium (BP). The present study describes calcium antagonistic effect of polyethylene glycol grafted bovine pericardium (PEG-GABP) with Fe2+/Mg2+ delivery from a co-matrix system in rat subcutaneous model. Retrieved samples were biochemically evaluated for calcification and alkaline phosphate (AP) activity. Scanning electron micrographs of 21-day explants had shown excessive calcification with glutaraldehyde treated BP (control). However, the PEG grafting and Fe/Mg release had substantially inhibited the deposition of calcium on BP. The extractable alkaline phosphatase activity was also reduced with PEG grafting and metal ion release to BP. The extractable AP had shown peak activity at 72 h [for GATBP—250.5 ± 1.2 nm pnp/mg protein/min enzyme activity (unit), PEG-GABP—165.2 ± 16.6 units], but markedly reduced after 21 days (22.1 ± 1.8 and 12.0 ± 1.5 units, respectively). The initial high levels may be due to tissue injury via surgery, which mitigated with time. It is assumed that ferric ions may slow down or retard the calcification process by the inhibition of proper formation of hydroxy apatite while magnesium ions disrupt the growth of these crystals by replacing Ca2+. In addition it may be hypothesized that these metal ions may inhibit the key element alkaline phosphatase, which acts as the substrate for mineralization. Hence, it is conceivable that a combination therapy via surface grafting of PEG and local delivery of low levels of ferric and magnesium ions may prevent the bioprosthesis associated calcification.
Sandwich Beams with Mid-Plane Asymmetry Subjected to Lateral Loads
Authors: Satapathy Nihar R. , Vinson Jack R.
Published: August 2002

The equations are presented by which to analyze, design and optimize sandwich beams which involve mid-plane asymmetry. Both classical beam theory and a refined theory involving transverse shear deformation are utilized. Explicit solutions for the beam subjected to a uniform lateral load for the boundary conditions of both ends clamped; both ends simply supported and a cantilevered beam are given. To obtain minimum face weight, the means to select each face thickness and the core depth are given for any given material system. In order to choose the face materials to achieve a minimum weight beam, a factor of merit is defined. Various materials are then compared.
Management of HIV-1 Infection in Adults and Adolescents
Authors: Eugenio Kenneth R. , Zeind Caroline S.
Published: August 2002

The management of Human Immunodeficiency Virus-1 (HIV-1) infection has undergone dramatic change since its initial identification. Advances have occurred in drug development, viral pathology understanding, laboratory monitoring and genetic analysis. With the advent of highly active antiretroviral therapy (HAART), there has been a substantial decline in HIV-1-related morbidity and mortality. Today, HIV-1 infection is treated as a chronic disease that requires strict patient adherence to HAART. Pharmacists provide pharmaceutical care to patients with HIV disease in a variety of ways, and they can improve patient adherence rates. Current therapeutic strategies have not resulted in eradication of HIV-1 infection. Present and future therapeutic challenges include viral resistance, reservoirs of virus and drug toxicities. Globally, the spread of HIV-1 infection continues at an alarming rate, and economic and social barriers may limit access and success of HAART. New strategies and novel approaches in managing HIV-1 infection continue to be developed in an effort to cure and eradicate this disease.
On Modeling of Global and Local Response of Sandwich Plates with Laminated Faces
Authors: Di Sciuval Marco , Icardi Ugo
Published: August 2002

The present paper investigates the influence of some non-classical effects (shear deformability of faces, warping of the cross section, static continuity requirements at the interfaces) on global response (thickness-wise distributions of the bending and transverse shear stresses) of sandwich plates with laminated faces. Parametric studies are performed for different values of the face to core thickness ratio and of the face to core transverse shear flexibility ratio by using smeared laminate models and discrete-layer models, small and large deflection theories. Also investigated is the effect of the unsymmetry of faces or of the sandwich plates as a whole. The numerical results show that (1) the fulfillment of the static continuity conditions is very important, especially for sandwich type construction having stiff faces and soft core, (2) when large deflections and unsymmetric sandwich constructions are involved, also the refined higher-order models fail to give correct prediction of the thickness-wise distributions of the transverse shear stress.
Experimental and Computational Study of APC-2/AS4 Thermoplastic Composite C-Rings
Authors: Yousefpour Ali , Ghasemi Nejhad Mehrdad N.
Published: August 2002

The mechanical performance of APC-2/AS4 thermoplastic composite C-ring samples with different processing conditions was investigated, and experimental results were compared with numerical results using finite element methods (FEMs). Mandrel/substrate preheating was found to be necessary for good-quality parts. Ten sets of samples, with five samples per set, were manufactured using in-situ thermoplastic composite filament winding. For the first five sets, tape preheated to below the glass transition temperature ( Tg) at 110°C was used, while the consolidation pressure for various sets was 5.5, 12.6, 19.4, 26.0, and 32.4 kN/linear-meter. The same pressures were used for the next five sets while the tape was preheated above the Tg at 170°C. Scanning electron microscopy (SEM) was used for quality control. C-ring tests were performed to evaluate failure stress, strain, and deflection of C-rings at room temperature. Samples failed in compression at ring mid-section and inner radius. Samples made with 12.6 and 19.4 kN/linear-meter consolidation pressures yielded the best results. Non-linear FEM was employed to simulate the C-ring experiment using shell, target, and contact elements. The experimental deflection to failure was applied to the model, and the failure stress, strain, and load were determined. The results from non-linear numerical analysis were slightly higher than those determined from available analytical solution.
Piezoelectric-Actuated Vibroacoustic Absorbers for Interior Noise Control
Authors: Green Kimball , Leo Donald J.
Published: August 2002

A damped vibroacoustic absorber is fabricated using piezoceramic material as the electromechanical actuator. The absorber consists of a conic piston attached to a system of flexures with surface-bonded piezoceramic material. The absorber is designed to couple the mechanical motion of the acoustic piston to the resonant dynamics of a closed acoustic cavity. Similar to a damped vibration absorber for a mechanical system, the resonance of the vibroacoustic absorber is tuned to the resonance of the closed cavity through proper design of the flexures. A localized model of the absorber coupled to the cavity dynamics is developed using Lagrangian techniques. The model incorporates the electromechanical coupling of the piezoelectric actuators and the impedance of the acoustic load with a mechanical model of the damper-piston arrangement. The model accurately predicts the dynamics of the absorber near the fundamental resonance but modeling errors increase at higher-frequencies because rotational inertia of the piston is neglected. Model-based feedback control laws are designed using full-state feedback and full-order observers. Experimental results demonstrate that closed-loop control of the absorber achieves approximately a 30% reduction in root-mean-square pressure response below the second cavity resonance. Feedback control is robust with respect to errors in the coupled absorber-cavity model, although performance degrades for high-gain feedback control laws. Sound reduction is achieved at multiple locations within the cavity, demonstrating that global noise attenuation is achieved through energy dissipation of the coupled system resonances.
Sensory Profile of Ewe’s Milk Cheeses
Authors: Bárcenas P. , Elortondo F. J. Pérez , Salmerón J. , Albisu M.
Published: August 2002

Sensory profiles for several ewe’s milk cheeses were developed and main sensory differences evaluated using a specifically designed methodology. It was stated that the existence of several clearly defined groups of sensory terms were negatively correlated. One group consisted of the attributes odor intensity, sharp odor, brine odor, rennet flavor, and butyric acid flavor. The other group consisted of milky odor, toasty odor, buttery odor and flavor, nutty flavor, and sweet flavor. Results pointed out that every descriptor except surface roughness showed a significant difference ( p< 0.01) among the samples. Main sensory differences were basically attributable to different manufacturing technologies as well as different ripening periods.
Impact Performance of Macrocomposite Laminates-2. Effect of Adhesive Layers
Authors: Akimoto H. , Toda M. , Miyashita J. , Shonaike G. O. , Hara S. , Murakami A. , Hogg P. J. , Ahmandinia A.
Published: August 2002

The effect of an adhesive layer on impact energy of macroscopic materials was studied. Both glass and carbon fibers reinforced plastic (GFRP and CFRP) composites were bonded to stainless steel using two types of adhesives: epoxy and ionomer. The FRP materials contain biaxial and quasiaxial fabrics. The impact properties of the FRP/stainless steel using the two types of adhesives were compared at both low (10 J) and high (120 J) energies. The results indicate that adhesive layer can make a significant contribution in improving the impact properties of composite materials. Ionomer adhesive proved to be more active than the epoxy adhesive as evident from degeneration of impact properties which was less than 20% while that of epoxy was as high as 30%. It was also observed that the deformation sustained by the stainless steel using epoxy adhesive was more severe than that of ionomer adhesive.
Analysis of Piezoelectric Smart Composites Using a Coupled Piezoelectric-Mechanical Model
Authors: Zhou Xu , Chattopadhyay Aditi , Thornburgh Rob
Published: August 2002

A two-way piezoelectric-mechanical coupled theory is used to investigate the multiple field interactions of composite laminates with surface-bonded piezoelectric actuators and sensors. A higher order electrical potential field is used to accurately describe the nonuniform distribution of electric potential through the thickness of piezoelectric layers. A higher order laminate theory is used to describe the displacement fields of both composite laminate and piezoelectric layers to accurately model transverse shear deformation which is significant in moderately thick constructions. A finite element laminate model with surface bonded/embedded piezoelectric actuators or sensors is developed to implement the theory. Induced deformation, charge and current are investigated to evaluate actuation and sensing effects of piezoelectric materials. The results obtained using this coupled theory are compared with those obtained using an uncoupled theory. Numerical results indicate that two-way coupling effects affect the prediction of structural deflection, stress distribution and electrical signal significantly. The thickness ratio of piezoelectric layer to plate structure is a critical parameter that governs the significance of coupling effects. The coupled piezoelectric-mechanical theory is capable of accurately modeling the characteristics of thick piezoelectric layers.
Dual-Preceptorship as a Method to Providing Consistent Clinical Clerkships in Community Pharmacy
Authors: Rogowski Amy C. , Strong Kathryn M.
Published: August 2002

In order to provide consistent clinical clerkships in community pharmacy, the University of Rhode Island College of Pharmacy uses a dual, or shared, preceptorship between site pharmacists and community pharmacy-based clinical faculty. Teams are developed with an assigned faculty member preceptor, then students are assigned to the individual team and clerkship site. Site preceptors provide students with daily activities and guidance while faculty preceptors enhance the experience with additional off-site clinical activities and team projects. This approach develops a strong partnership between the university and community pharmacies with the common goal of providing quality patient care services in the community.
Scintigraphic Assessment of the Regional Distribution and Kinetics of Pharmaceuticals
Authors: Berridge Marc S. , Lee Zhenghong
Published: August 2002

A lesser known use of imaging studies in drug development is to determine the patterns of deposition, biodistribution, and regional kinetics of drugs in the body. This kind of study is of most interest when the drug is intended for local action following topical administration by inhalation. Imaging provides a convenient noninvasive method for observing initial deposition patterns and their variations caused by variables of the drug’s formulation and delivery method. Though planar gamma imaging is the method that has most often been used, recent years have seen promising demonstrations of SPECT and PET imaging to provide three-dimensional and quantitative measurements of drug deposition. When the goal of a drug is direct local treatment of diseased tissue, delivery of that drug is an important therapeutic variable. Imaging studies allow the drug delivery to be measured and optimized before a drug formulation is committed to clinical trials.
Effect of the Curing Systems on the Fatigue Behavior of NR Vulcanizates
Authors: El-Sabbagh S. H. , Ismail M. N. , Yehia A. A.
Published: August 2002

In the present work, the effect of different network structures, created in natural rubber vulcanizates by different curing systems, on the fatigue behavior was studied. The accompanying changes in the physico-mechanical properties of unfilled and filled rubber vulcanizates was also studied. It was found that the physico-mechanical properties greatly depend on the curing system used. Scanning electron microscopy (SEM) was used to study the failure mechanism of rubber. The SEM results show the changes in network structure of the natural rubber vulcanizates, which have undergone fatigue failure via flexing. On the other hand the loading of rubber compounds with reinforcing filler increases stiffness, improves the mechanical properties and decreases the resistance to fatigue of the resultant vulcanizates.
Estimation of the Effective Permeability in Magnetorheological Fluids
Authors: Simon T. M. , Ito K. , Banksa H. T. , Reitich F. , Jolly M. R.
Published: August 2002

Magnetorheological (MR) fluids constitute examples of controllable ("smart") fluids, whose Theological properties vary in response to an applied magnetic field. These fluids typically consist of micron-sized, magnetizable particles dispersed in a nonpermeable carrier fluid. The essential characteristic of MR fluids is that they may be continuously and reversibly varied from a state of free flowing liquids in the absence of an applied magnetic field to that of stiff semi-solids in a moderate field. Understanding the magnetic properties of MR fluids is crucial to the design of MR fluid-based devices and it also provides valuable insight into the character of the microstructure responsible for their field-dependent rheology. Prediction of the overall magnetic properties of MR composites is a challenging task, however, due to the highly nonlinear and strongly spatially variable nature of the magnetization of the constituents. In this paper we propose a model for this behavior that is based on the mathematical theory of homogenization. We derive effective equations that govern the magnetic response of (periodically arranged) particle-chains through magnetic saturation. Comparisons of numerical results for these equations with experimental data show good agreement which suggests that our approach could be useful in the design of improved MR fluids.
Polymer Matrix Woven Fabric Composites Subjected to Low Velocity Impact: Part II-Effect of Plate Thickness
Authors: Naik N. K. , Meduri Sailendra , Sekher Y. Chandra
Published: August 2002

The studies have been carried out on the damage initiation behavior of polymer matrix woven fabric (WF) composite plates subjected to a transverse central low velocity point impact load. Specifically, the effect of composite plate thickness on the impact behavior has been investigated with a square plate of 150 mm x 150 mm with thicknesses varying from 4.5 mm to 8.0 mm. The material systems considered are: E-glass/epoxy and T300/5208 carbon/epoxy. Inplane failure of the layers in the form of matrix cracking/lamina splitting and delaminations were the primary objectives of the study. The studies have been carried out using an inhouse Finite Element Analysis (FEA) code. The inplane failure functions and the interlaminar failure functions have been predicted using quadratic failure criteria. General observations on the impact behavior of polymer matrix WF composites as a function of plate thickness have been presented.
Characterization of Matrix Crack-Induced Laminate Failure—Part I: Experiments
Authors: Johnson Patrick , Chang Fu-Kuo
Published: August 2002

An investigation was performed to study the impact of matrix cracking-initiated damage on the response and the strength of composite laminates subjected to uniaxial tension. Both experiments and analysis were conducted during the investigation. Extensive tests were performed on specimens with specially tailored ply orientations to characterize damage initiation and propagation induced by matrix cracks. The focus of the experiments was to characterize the matrix crack-induced damage progression and failure modes in composite laminates under uniaxial tension loads. Four basic damage modes were observed from the results of the study: matrix crack-induced microcracking, matrix crack-induced delamination, angle-ply-induced edge delamination, and Mode I edge delamination. The results of the experimental study are presented in this paper. Results from the analytical work will be presented in a subsequent paper.
Prediction of Natural Frequencies of a Sandwich Panel Using Thick Plate Theory
Authors: Liu Qunli , Zhao Yi
Published: August 2002

The vibration of a sandwich panel with two identical isotropic facesheets and an orthotropic core was studied. The governing partial differential equation was derived using a variational principle. Linear shear theory was employed to describe the transverse deformation of the panel, and the rotational effect was taken into consideration. The natural frequencies of a rectangular sandwich panel can be predicted on the basis of the proposed analytical model. Results from the proposed model were compared with those from thin plate theory. The effects of the structural and material parameters such as core anisotropy, core density, and facesheet thickness on natural frequencies were discussed.
Energy Release Rate of Double Beam-Plates with Repairing Elements
Authors: Lin Chien-Chang , Wang James Ting-Shun
Published: August 2002

An engineering analysis for determining the strain energy release rate of symmetrically loaded double beam-plates with repairing or reinforcing elements in the transverse direction which are densely distributed across the width in the disbond regions is presented. The concept of strain energy release rate evaluated by computing the rate of energy released from the disbond front has been verified to be exactly the same and simpler to use than the most referenced work of Kanninen by differentiation of the total strain energy of the entire system with respect to the disbond length. Due to the simplicity of the new concept for determining the strain energy release rate, it allows one to derive the exact analytical solutions for double beam-plates containing repair or reinforce elements and satisfying continuity at the delamination front as well as boundary conditions at both ends of the system. Some comparisons of the strain energy release rate for double beam-plates without repair elements to other approximations are also made. Each side of a double beam-plate system in the perfect segment is modeled as a beam-plate on an elastic foundation, while disbond segments are treated as beam-plates under transverse loading and constrained by repairing or reinforcing elements as axially loaded members at discrete points. Some numerical results for a double cantilever beam-plate with one and two rows of reinforcing elements under end loads are presented for illustrating the procedure as well as for future reference. The general concept and analysis procedure should be applicable to other structural systems and for mixed-mode delaminations.
Response and Failure of Internally Pressurized Elliptical Composite Cylinders
Authors: McMurray Jennifer M. , Hyer Michael W.
Published: August 2002

The responses of a quasi-isotropic elliptical cylinder evaluated using a geometrically linear analysis are compared to the responses evaluated using a geometrically nonlinear analysis. It is shown that geometric nonlinearities tend to flatten certain responses in the crown region and reduce the magnitude of certain responses in the boundary region. An evaluation of failure using the Hashin and maximum stress failure criteria and geometrically linear and nonlinear analyses is presented. The failure criteria are used to assess the mode of failure, the location of failure, and the pressure at failure. Both criteria predict first failure to occur at the clamped boundaries because of matrix cracking due to stresses in the plane of the cylinder wall. The predicted failure pressures and circumferential locations are very similar for the two criteria, and the nonlinear analyses predict slightly higher pressures at somewhat different circumferential locations.
Testing and Modeling a Cone-Shaped Squeeze-Film Mode Electrorheological Damper
Authors: Wang X. J. , Zhang P. Q. , Tang X. , Tao R.
Published: August 2002

Experiments on a cone-shaped squeeze-film mode ER damper are reported. An analytical model is developed to calculate the damping force as a function of the vibration amplitude, frequency, the yield stress of the ER fluid. Our calculations agree with the experiments very well at small amplitudes. The cone-shaped electrodes make the damper benefit from both shear mode damper and squeeze-film mode damper. The azimuth angle 0 of the cone electrodes plays an important role in magnifying the damping coefficient of this new type of ER damper.
Helicopter Vibration Reduction through Cyclic Variations in Rotor Blade Root Stiffness
Authors: Anusonti-Inthra Phuriwat , Gandhi Farhan
Published: August 2002

This study analytically examines the influence of cyclic variations in flap-, lag-, and torsion-stiffness of the blade root region (at harmonics of the rotational speed), for reduction of vibratory hub loads of a helicopter in forward flight. The results indicate that considerable reduction in hub vibrations is possible using small-to-moderate amplitude cyclic variations in stiffness (no greater than 15% of the baseline stiffness value). Torsion stiffness variations produced moderate reductions in vertical hub force, lag stiffness variations produced substantial reductions in all hub forces and the hub yaw moment, and flap stiffness variations produced very significant reductions in all hub forces and the hub roll and pitch moments. The amplitude of the cyclic stiffness variations required generally increase with increasing forward speed, for comparable reductions in vibration. At any given forward speed, if the amplitudes of cyclic stiffness variation are too large, the hub vibrations can actually increase. The stiffness variations that reduce the vibratory hub loads could produce increases in certain vibratory blade root load harmonics. Vibration reductions are achieved due to a decrease in the inertial contribution to the hub loads, or a change in relative phase of various contributions.
The Effects of Glass Fiber Reinforcement at Different Concentrations on the Transverse Strength, Deflection and Modulus of Elasticity of a Provisional Fixed Partial Denture Resin
Authors: Keyf Filiz , Uzun Gülay
Published: August 2002

This study focused on some mechanical properties such as the transverse strength, maximal deflection and modulus of elasticity of a resin reinforced with untreated, chopped form glass fibers at different concentrations. A Teflon mould was used to prepare four groups of specimens. The specimens were prepared with different concentrations of the glass fiber to the mass of the powder/liquid mix (0.5, 1, 1.5%), and a mix without fiber was used as the control group. All the specimens were subjected to transverse testing with a cross-head speed of 5 mm/min. The load to fracture for each specimen with the maximum deflection at the point of loading in a three-point load test was recorded. The transverse strength of 0.5% fiber concentration was 54.45 MPa. The lowest value was 49.67 MPa for the 1% fiber concentration. The highest mean strength was for the specimens reinforced with 0.5% glass fiber. This mean was higher than for the mean of the control “without fiber” specimens. The specimens demonstrated an insignificant decrease in the transverse strength and the maximum deflection when the fiber concentration was increased. The inclusion of 1% glass fiber reduced the transverse strength, although the result was not statistically significant.
A Micromechanics-Based Hysteresis Model for Ferroelectric Ceramics
Authors: Li J. , Weng G. J.
Published: August 2002

Based on the mechanics of domain switch and irreversible thermodynamics, a micromechanics-based model that incorporates the effect of polarization strain and electric polarization in the switched domain is developed to predict the evolution of new domain and the associated hysteresis loops of a ferroelectric ceramic. The new domain concentration c r associated with the remanent polarization P r, and the new domain concentration c c at the coercive field E c, are also found in terms of the saturation polarization P s, the coercive field E c, and the dielectric permittivity of the parent domain. The theory is developed with a homogenization technique for a coupled, dual-phase electromechanical system with an evolving microstructure, whose driving force arises from the reduction of Gibbs’ free energy and whose resistance force comes from the energy dissipation due to domain wall movement. The developed theory is applied to a lanthanum doped lead zirconate titanate (PLZT), first for the calculation of its hysteresis electric displacement versus electric field ( D vs. E) relation and the butterfly-shaped longitudinal strain versus electric field (∊ vs. E) relation, and then for its nonlinear compressive stress-strain relation and nonlinear depolarization. The results are shown to provide the essential features of the hysteresis behavior and found to be in quantitative accord with the experimental data.
Cigarette Ignition Performance
Authors: Wanna J. T. , Chen P. X.
Published: August 2002

Two sample cigarettes (coded B and D) along with a control were tested according to the two cigarette ignition propensity test methods published by the National Institute of Standards and Technology (NIST). The primary test uses duck fabrics over polyurethane foam in a flat configuration, and the secondary test uses Whatman #2 filter paper. The three cigarettes were also tested on commercial upholstery fabrics in the flat and crevice configurations. Cigarettes B and D used 80 CORESTA cigarette paper with 5.5 mm and 6.5 mm wide bands, respectively. The control used 33 CORESTA paper with no bands. Cigarettes B and D produced significantly less ignitions than the control on duck fabrics and >90% self-extinguishment (SE) compared to 0% SE for the control on 10 layers of filter paper. However, the cigarettes with bands produced significantly more ignitions on duck fabrics #6 and #10 when smoldered horizontally vs. vertically (NIST proposed smoldering position) prior to placing on the mockup. On 25 commercial upholstery fabrics tested in a flat configuration, cigarettes B and D produced 5% fewer ignitions than the control, which was significantly different. However, on 22 commercial upholstery fabrics tested in the crevice configuration, B and D produced 4% or fewer ignitions than the control, which was not a significant difference. No significant differences were obtained in any test between cigarettes B and D, which used different band widths. A self-extinguishing cigarette on an arbitrary set of layered filter papers does not inherently translate to “fire-safe cigarette.”
Integration of Web-Based Computer-Aided Instruction into a Nontraditional Doctor of Pharmacy Program
Authors: Grillo Joseph A. , Stolte Scott K. , Lewis Jeffrey , Robinson Evan T.
Published: August 2002

The rapid change in technology in recent years has provided the impetus for many instructors to revisit their ideas about learning and student-teacher interactions. Computers offer an easy exchange of text-based and graphic material and increasingly, the ability to observe and hear others in real-time interactions. The use of technology as an instructional delivery tool has, in many cases, changed the way faculty teach. Teaching online can be challenging and it helps to start slowly and work up to the more complicated and involved pedagogical models.

This paper discusses studies evaluating the effectiveness of computer-aided instruction (CAI), offers suggestions for developing a web-based CAI program, relates the experiences of one college of pharmacy with CAI, and offers teaching tips for the digital age.
Estimation of the Long-Term Dimensional Stability Performance of Hydrocarbon Blown Rigid Polyurethane Foams for Insulation—A Novel Approach
Authors: Kaneda T. , Hayashi O. , Shibata M. , Kawasaki H. , Inoue H. , Fujino H.
Published: August 2002

For years, HCs with zero ODP and low GWP have been used as alternative B.A. (blowing agents) in the appliance industries. The improvement of insulation performance and lowering costs are significant factors in the development of R-PU (rigid polyurethane) foams especially blown with HCs. The development of R-PU foam with a lower density for cost effectiveness is progressing at present. Positive experiences as to the long-term dimensional stability of pentane blown R-PU foam accelerated this movement. The most important factor in the development of R-PU foam with a lower density is long-term dimensional stability. In this report, we propose a novel long-term dimensional stability test and its appropriateness is discussed. The influence of formulation and the boiling point (B.P.) of B.A. on long-term dimensional stability have also been studied. The use of a blowing agent mixture of cyclopentane and iso- or n-pentane with a lower B.P. allowed the achievement of density savings. The understanding of the relation between the formulation and long-term dimensional stability is an important issue for the development of R-PU foam.
Performance Metrics for Composite Integral Armor
Authors: Fink Bruce K.
Published: August 2002

Future combat systems necessarily focus on lightweight, highly mobile and transportable armored vehicles. Lightweight composite integral armor systems are being developed to meet these needs. The goal of this paper is to centrally document the myriad design requirements for composite integral armors that serve multifunctional roles including ballistic, structural, shock, electromagnetic, and fire protection. Structural and ballistic performance requirements as well as manufacturing and life-cycle performance issues of integral armor are presented. Specific areas addressed include high-strain-rate testing and modeling, ballistic testing and modeling, low-cycle fatigue, damage tolerance, repair, reduced-step processing, through-thickness reinforcement, energy dissipation and rate-dependent failure mechanisms, and non-linear mechanics.
Effective Mechanical Properties of Materials with Coated Inclusions
Authors: Aboutajeddine A. , Vu-Khanh Toan
Published: August 2002

In this work the effective properties of materials containing coated inclusions are analyzed. The analysis is based on a double-homogenization realized with the aid of Hill’s interfacial operators, Eshelby’s solution for ellipsoidal inclusion, and the Mori-Tanaka scheme. The system inclusion-coating is assumed to consist of two confocal spheroids. The proposed approach gives closed-form solutions and holds for both thin and thick coatings.
Thermal Buckling of Laminated Composite Beams with Embedded Shape Memory Alloy Actuators
Authors: Choi Sup , Lee Jung Ju , Lee Dong Chun
Published: August 2002

In this paper, the thermal buckling and postbuckling behaviours of a composite beam with embedded shape memory alloy (SMA) wires are investigated experimentally and analytically. For the purpose of enhancing the critical buckling temperature and reduction of the lateral deflection on thermal buckling and postbuckling, the characteristics of thermal buckling are investigated through the use of the shape recovery force. The results of thermal buckling tests using uniformly heated and clamped composite beam specimens with embedded SMA wire actuators are discussed. The temperature-load-deflection behaviour records present quantitatively how the shape recovery force affects the thermal buckling behaviour. For this experiment, we considered the initial geometric imperfections, the slenderness ratio of the beam and the embedding position of the SMA wire actuators. The experimental results show that the shape recovery force reduces the thermal expansion of the composite laminated beam. This results in an increase of the critical buckling temperature and a reduction of the lateral deflection of the beams.
Characterizing Stiffness and Strength Properties of Glass-Fiber Reinforced, Hollow-Cored Recycled Plastic Extrusions
Authors: Engblom John J. , Zheng Zhiyin
Published: August 2002

Hollow-cored structural profiles have been processed using blends of polyethylene with continuous glass-fiber roving reinforcement through an offset extrusion process. These profiles have been produced with and without coupling agents. The intent has been to achieve high bending stiffness (El) by locating the reinforcing fibers in the mid-plane of the extrusion walls. However, the process was not optimally tuned which results in the fibers being nearer the inner surfaces of extrusion walls. Four-point bending and compression tests have been performed on the hollow-cored beams according to ASTM D6109 and ASTM D61 12. The nonlinear elastic nature of the unreinforced plastic blends has been quantified by performing tensile tests according to ASTM D638. A finite element-based computational model has been developed through the assembly of "repeating cells" representing individual fiber rovings and neighboring plastic. Comparing experimental and computational results demonstrates the validity of the model in predicting bending stiffness (El). Furthermore, simple multi-material beam models are shown to over-predict bending stiffness. The experiments also provide evidence suggesting shear failure at fiber-matrix interfaces.
Smart Laminated Shells and Deflection Control Strategy with Optimal Voltage
Authors: Bhattacharya P. , Suhail H. , Sinha P. K.
Published: August 2002

The present paper deals with a finite element analysis procedure for smart laminated composite shells based on Reissner' s principle. Hermitian polynomials have been used for the development of curved surfaces and these permit the construction of any arbitrary shell geometry. The piezoelectric constitutive equations are incorporated in the shell structural constitutive equations. The finite element codes are accordingly developed and results are obtained for various composite laminated shell panels. A deflection control strategy is proposed based on pseudo-inversion and modified Lavenberg-Marquardt's optimization algorithms. A smart laminated beam is considered as a case study for evaluating the proposed deflection control strategy. Results are obtained for various locations of the piezoelectric patches and it is observed that the strategy can be effectively used for the deflection control of a beam. The method so developed may also be applied to any piezo-laminated plate or shell configuration.
Permeability of WIPP Salt during Damage Evolution and Healing
Authors: Chan Kwai S. , Bodner Sol R. , Munson Darrell E.
Published: August 2002

The presence of damage in the form of microcracks can increase the permeability of salt. In this paper, an analytical formulation of the permeability of damaged rock salt is presented for both initially intact and porous conditions. The analysis shows that permeability is related to the connected (i.e., gas accessible) volumetric strain and porosity according to two different power-laws, which may be summed to give the overall behavior of a porous salt with damage. This relationship was incorporated into a constitutive model, known as the Multimechanism Deformation Coupled Fracture (MDCF) model, which has been formulated to describe the inelastic flow behavior of rock salt due to coupled creep, damage, and healing. The extended model was used to calculate the permeability of rock salt from the Waste Isolation Pilot Plant (WIPP) site under conditions where damage evolved with stress over a time period. Permeability changes resulting from both damage development under deviatoric stresses and damage healing under hydrostatic pressures were considered. The calculated results were compared against experimental data from the literature, which indicated that permeability in damaged intact WIPP salt depends on the magnitude of the gas accessible volumetric strain and not on the total volumetric strain. Consequently, the permeability of WIPP salt is significantly affected by the kinetics of crack closure, but shows little dependence on the kinetics of crack removal by sintering.
Current Issues in Gram-Negative Resistance: Extended-Spectrum Beta-Lactamases and Inducible Beta-Lactamases
Authors: Fung Horatio B. , Kuczynski Stephen , Finch Douglas A. , Ramos Liz
Published: August 2002

The production of beta-lactamases is the most common cause of antimicrobial resistance in gram-negative bacilli. Two beta-lactamases, extended-spectrum beta-lactamases (ESBLs) and inducible beta-lactamases (IDBLs), are presently seen with increasing frequency. Treatment of severe infections due to gram-negative bacilli producing these beta-lactamases is problematic. In vitro susceptibility testing of ESBL-producing organisms remains difficult to interpret; clinical isolates sensitive to a particular antimicrobial agent at standard inoculum may become resistant when a higher inoculum is employed. Laboratory detection of IDBL-producing organisms is not yet commercially available. Due to the lack of sufficient outcome data, clinicians often have no choice but to use carbapenems empirically for the treatment of severe infections caused by organisms suspected of producing these enzymes. The widespread empiric use of carbapenems is of concern and may potentially precipitate increased bacterial resistance to this class of antimicrobial agents.
Estimation of Internal Stresses in Shape Memory Wires during Thermal Cycling under Constant Load: A Macromechanical Approach
Authors: de Araújo Carlos José , Morin Michel , Guénin Gérard
Published: August 2002

Untrained shape memory alloys are very sensitive to the introduction of defects associated with the accumulation of plastic strain during thermomechanical cycling. These defects are responsible for the creation of an internal stress field that plays a fundamental role on the macroscopic memory properties (superelasticity and shape memory effects). In this paper a simple physical model based on a macroscopic analysis is developed for the evaluation of the global internal stress field created in Ti-Ni based shape memory wires during thermal cycling under constant load. The results obtained with this macromechanical approach are supported by calorimetric and electrical resistance (ER) measurements performed after failure of the material.