Modulus

Subgrade performance is a function of a soil's strength and its behaviour under traffic loading. The subgrade should be stable to prevent excessive rutting and shoving during construction, provide good support for placement and compaction of pavement layers, keep pavement rebound deflections to acceptable limits, restrict the development of excessive rutting during the service life of the pavement and minimise effect of changes in moisture level.

In this study, 31 empirical equations are summarized that relate unconfined compressive strength and internal friction angle of sedimentary rocks (sandstone, shale, and limestone and dolomite) to physical properties (such as velocity, modulus, and porosity). These equations can be used to estimate rock strength from parameters measurable with geophysical well logs. The ability of these equations to fit laboratory-measured strength and physical property data that were compiled from the literature is reviewed. Results from this study can be useful for petroleum industry when a range of geomechanical problems such as wellbore stability and in-situ stress measurements should be addressed without direct strength information available. While some equations work reasonably well (for example, some strength-porosity relationships for sandstone and shale), rock strength variations with individual physical property measurements scatter considerably, indicating that most of the empirical equations are not sufficiently generic to fit all the data published on rock strength and physical properties. This emphasizes the importance of local calibration before one utilizes any of the empirical relationships presented. Nonetheless, some reasonable correlations can be found between geophysical properties and rock strength that can be useful for applications related to wellbore stability where having a lower bound estimate of in situ rock strength is especially useful.

We review recent developments in modeling mechanical properties of segmented polyurethanes. Polyurethanes, poly(urethaneureas), polyureas, and polyisocyanurate materials are widely used in a variety of industries due to the versatility of their properties. We concentrate on segmented polyurethane elastomers and discuss the relationship between formulation variables, polymer morphology, and polymer mechanical properties (Young's modulus, tensile stress-strain curves, etc.). Specifically, we show how one can derive predictive structure-property relationships by combining thermodynamic block copolymer theory with micromechanical models. The resulting predictions for Young's modulus and stress-strain curves compare favorably with experimental data.

Polymer mortars have become more popular as repair materials compared to conventional mortars. This paper reports the investigation on different mechanical properties of polyester mortar cured at ambient temperature and 80 o C. Unsaturated polyester resin, which is known for its cost performance efficiency is used to bind the aggregates. A comparative study was made on properties of polymers. It was found that thermal cured specimens exhibited improved compressive, flexural and split tensile strength compared to ambient cured specimens. However ambient cured samples exhibited a greater modulus than thermal cured samples. Since the polymer mortar exhibits high modulus of elasticity and ductility, it can be recommended as building materials for construction of earthquake retaining structure, repair works etc...

Relatively little is known about how diagenetic processes affect the mechanical properties of mineralized tissues such as vertebrate bones. Diagenesis can involve the alteration of bone's organic phase, mineral phase, and structural organization, all of which contribute to bone's nanomechanical properties. Nanoindentation allows submicrometer investigation of alterations in bone properties that occur during diagenesis. In this preliminary study, the nanomechanical properties (modulus and hardness) of recent and fossil bone were compared through the use of depth-sensing nanoindentation. Additionally, X-ray diffraction and density measurements were used to investigate changes in the mineral phase. Nanoindentation revealed that the basic mechanical anisotropy of modern bone can be preserved in fossil bones going back at least to the early Eocene (∼ 50 Ma), as the elastic modulus (i.e., stiffness) values measured perpendicular to the long axis of each bone sample were consistently lower than longitudinal values (as is the case for modern bones). While a general increase in mechanical properties was observed with the geological age of the samples, a relatively small increase was seen in fossil bone samples older than the Miocene, suggesting that mineral infilling is limited by spatial saturation, as the modulus approached that of fully dense minerals such as quartz or apatite. Further, evidence for modification of the mineral phase was demonstrated by an increase in crystallinity and density with the geological age of the bone. Both increased crystallinity and density correlated with increased modulus values, suggesting that the size and perfection of the bioapatite crystals contribute to the mechanical properties of the bones. Rather unexpectedly, the early Oligocene-aged bones demonstrated reduced modulus and hardness values compared to the Miocene and Eocene samples, which we hypothesize to be related to the diagenetic environment. Specifically, the fossil-bearing strata at the Oligocene-aged locality contain volcanic ash which is known to dissolve bone minerala plausible cause for the decreased mechanical properties of the Oligocene bones. Our study demonstrates that nanoindentation, a relatively nondestructive tool, is useful in investigating tissue-level diagenesis in bone that cannot be seen with the naked eye, and can provide insight into the functional significance of mineralized tissues even after diagenesis has occurred.

The ultimate parameter of interest in engineering design of compacted subgrades and support fills for highways, railroads, airfields, parking lots, and mat foundations is often the soil modulus. Modulus of compacted soils depends not only on dry unit weight and moisture but also on matric suction and soil structure (or fabric) resulting from the compaction process. However, these relationships in the as-compacted state (i.e., immediately after compaction) have not yet been extensively explored. This paper presents an experimental laboratory study of the shear modulus -matric suction -moisture content-dry unit weight relationship using three compacted subgrade soils. Compacted subgrade specimens were prepared over a range of molding water contents from dry to wet of optimum using enhanced, standard, and reduced Proctor efforts. A nondestructive elastic wave propagation technique, known as bender elements, was used to assess the shear wave velocity and corresponding small-strain shear modulus (Go) of the compacted subgrade specimens. The matric suctions were measured with the filter paper method. An empirical relation that takes into account the effect of compaction conditions is proposed for the Go -matric suction -molding water content relationship of compacted subgrade soils.

► Here, a new class of high-performance composites, called “Lightweight Flexible Nonlinear Composites (LFNLC)”, has been briefly introduced. This class of composites has its own structural and functional characteristics as Nonlinear behavior in bending and porous or porous-like texture.

♦ The cementitious LFNLC is termed “Elastic Composite, Reinforced Lightweight Concrete (ECRLC)”. The ECRLC provides lightweight beams with substantial strain capability, resilience modulus and toughness in bending, resulting in a considerable increase in bearing capacity while weighing significantly less. The failure mode in low-height and ultra-lightweight beams made of the ECRLC is not compressive and brittle.

♦ This lightweight, flexible composite is a non-monopolistic, versatile and comparatively low-price material. Likewise, the virtues such as resilience and flexibility, workability, lightness, durability, and high formability are important in architecture.

♦ In general, lightweight and integrated construction has a key importance in earthquake resistance. Therefore, the ECRLC can be especially beneficial in earthquake-prone regions.

♦ Considering the flexibility and resilience of this formable system, it can also be used to build non-brittle reinforced ultra-lightweight and insulation sandwich panels, safe and lightweight guards, and shock-resistant structures. Likewise, they are utilizable in some infrastructures and explosion-proof pieces with suitable behavior, resilience, and toughness.

♦ This work presents a practical method for converting a rigid solid into a flexible material with lower density or increasing the elasticity of a flexible material while decreasing the density. Essentially, this method entails creating a porous or porous-like texture in the material, reinforcing appropriately, and providing it with the necessary integrity. (For example, properly dispersing lightweight aggregates all over the reinforced, conjoined matrix can produce a porous-like texture.) By this process, the resilience modulus and toughness in bending rise and the density reduces.

♦ This paper briefly presents the functional and structural characteristics of the LFNLCs and some applications and Reproducible examples of the ECRLC.

The pericellular matrix (PCM) is a narrow tissue region that surrounds chondrocytes in articular cartilage. Previous parametric studies of cell-matrix interactions suggest that the mechanical properties of the PCM relative to those of the extracellular matrix (ECM) can significantly affect the micromechanical environment of the chondrocyte. The goal of this study was to use recently quantified mechanical properties of the PCM in a biphasic finite element model of the cell-PCM-ECM structure to determine the potential influence of the PCM on the mechanical environment of the chondrocyte under normal and osteoarthritic conditions. Our findings suggest that the mismatch between the YoungÕs moduli of PCM and ECM amplifies chondrocyte compressive strains and exhibits a significant stress shielding effect in a zone-dependent manner. Furthermore, the lower permeability of PCM relative to the ECM inhibits fluid flux near the cell by a factor of 30, and thus may have a significant effect on convective transport to and from the chondrocyte. Osteoarthritic changes in the PCM and ECM properties significantly altered the mechanical environment of the chondrocyte, leading to $66% higher compressive strains and higher fluid flux near the cell. These findings provide further support for a potential biomechanical role for the chondrocyte PCM, and suggest that changes in the properties of the PCM with osteoarthritis may alter the stress-strain and fluid flow environment of the chondrocytes.

Chemical polymerization of pyrrole within aqueous polyvinyl alcohol (PVA) solution gives rise to a nanodispersion with unique stability and monodispersity. The nanodispersion has shown uniform distribution of perfectly spherical $110 nm polypyrrole particles (from transmission electron microscopy and dynamic light scattering) with high doping level (from UV-Vis analysis) and sufficient electrical conductivity (10 À3 S/cm). The dispersion with optimum stability and conductivity was subjected to viscoelastic studies. The viscosity of the system was adjusted by dilution with water and shear thinning (under steady shear) was generally observed. Dynamic mechanical studies have shown that the dispersion behaves like a semidiluted polymeric solution that roughly follows the Zimm model of viscoelasticity. This behavior accounts for its unique stability and miscibility with water at any proportion without precipitation. On drying or leaving the sample for 7 days, Fe 3þ induced partial crosslinking of PVA chains takes place via -OH groups, although complete gelling does not occur. The dispersion forms flexible and uniform films on glass and metal surfaces that does not dissolve after complete drying; this observation combined with shear thinning encourages its application as ink or paint. V C 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 792-800, 2011

Large-scale cyclic simple shear tests were conducted on reconstituted specimens of municipal solid waste (MSW) collected from the Tri-Cities landfill in Fremont, California, USA. The influence of waste composition and compacted unit weight on the shear wave velocity, small-strain shear modulus, and straindependent shear modulus reduction and damping ratio curves of MSW was investigated in these tests. Modulus reduction and damping ratio curves were evaluated over a strain range of 0.01-3%. Specimens were reconstituted using 100%, 65%, and 35%, by weight, of the material that passed through a 20 mm screen and four different levels of compaction effort. All specimens were consolidated under a normal stress of 75 kPa prior to testing. The test results show a very strong dependence of shear wave velocity and small strain shear modulus on unit weight. Unit weight also had an influence on modulus reduction and damping ratio. Waste composition had a very strong influence on damping and also influenced shear wave velocity, small strain shear modulus, and modulus reduction. The interrelationship between unit weight and waste composition made it difficult to separate out the effects of these parameters.

In this work, a new approach to spherical nanoindentation analyses has been described and utilized to study the anisotropy of mechanical properties for (100) and (001) LaGaO3 single crystals. Unlike sharp indenters, indentations by spherical indenters permit the nanoindentation load–displacement curve to be converted more reliably into indentation stress–strain curves. Using a new definition of indentation strain, we present indentation

In the present paper, the gallium modified lead zirconate titanate ceramics with Zr/Ti = 48/52 (near the mor-photropic phase boundary, MPB), having a chemical formula Pb 0.98 Ga 0.02 (Zr 0.48 Ti 0.52) 0.995 O 3 , was synthesized by a mixed-oxide reaction method and sintered. Analysis of phase formation confirmed the coexistence of two phases (tetragonal and monoclinic symmetry) in the system. Microstructural study by scanning electron microscope showed a non-uniform distribution of large grains over the sample surface and presence of a small amount of micro-size pores. Modulus and impedance studies were carried out at various frequencies (1 kHz– 1 MHz) and temperatures (300–350 °C) and showed the contributions of grains in capacitive and resistive properties of the material. The resistance and capacitance of the complex impedance plots are contributed by grains as observed from the Nyquist plots. The experimental data obtained from the Nyquist plot were implemented in an equivalent electrical circuit (RQC). The value of grain resistance and capacitance were obtained using fitting steps with precision at all temperatures. It is assumed that increase of dielectric constant at higher temperatures is due to the substitution of Ga + ions at the Pb-site.

The results of an experimental work on two road granular materials are presented, including small strains precision triaxial tests under cyclic loading, large strains triaxial tests with measurement of the negative pore water pressure (suction) and wetting tests. The influence of different initial conditions of density, water content and fines content was studied. The two ma- terials differ by their fine contents (7 % for MHC and 10% for HFC). The specimens are com- pacted at different water content and at a density corresponding to 97% of the Modified Proctor maximum density. The interpretation of the results, in the quasi-elastic domain, is based on an effective stress analysis that allows to take into account both the effects of total stresses and nega- tive pressure, in the perspective of a more rational design of pavement layers.

Deformation Pile-up/sink-in Knowledge of the elastic constants of zeolite films is of great practical interest, due to its main applications. The structural and nanomechanical properties of a faujasite-type zeolite film have been measured using nanoindentation. The hardness and elastic moduli of the film are estimated from creep and non-creep nanoindentation measurements. The deformation mechanism was analyzed using a pile-up/sink-in analysis, revealing a switch of dominant deformation mechanism at~250 nm of displacement. Wear analysis (hardness to elastic modulus ratio) provided information about the structural integrity and mechanical reliability of the film. Hardness and elastic modulus values were found to decrease with increasing penetration depth. In particular, the elastic modulus decreased from~60 GPa (at displacement of 20-30 nm) to~7 GPa (at displacement of 200 nm), and the hardness from~8 GPa (at displacement of 20-30 nm) to~0.8 GPa (at displacement of 500 nm).

Purified polyester commonly referred to as polyethylene terephthalate (PET) fibres were treated in four chlorinated solvents: perchloroethylene (PCE), trichloroethylene (TCE), 1,1-dichloroethylene (1,1-DCE) and tetrachloromethane (TCM) at room temperature for various time intervals of 30, 60, 150, 300, 450, 600, 750, 900 and 1800 seconds to induce structural modifications of the PET fibre. The effects of these treatments in a relaxed condition on the tensile properties of the treated polyethylene terephthalate (PET) fibres for modulus (MPa), tenacity (MPa) and extension at break (mm) were determined. A fall in the initial (Young's) modulus of all the treated fibres compared to the control ones was noticed, this may be due to the reduction in stiffness of the phenyl residue on the terephthalate group. The increase in the tenacity and extension at break of the treated fibres compared to the control ones could be linked to the stability conferred on them by the solvent treatments and the convolution occurring from chain folds in the treated fibres. Tetrachloromethane (TCM) was found to give the highest stable equilibrium tenacity and extension at break values within the first 600 secs of the treatments while these two quantities continue to vary with increase in time of treatment for the other three solvents. The stability of these two quantities in TCM treated fibres at shorter treatment time is a useful indication of textile materials that would not be deformed easily during processing and dry cleaning operations.

Tendon is a highly specialized, hierarchical tissue designed to transfer forces from muscle to bone; complex viscoelastic and anisotropic behaviors have been extensively characterized for specific subsets of tendons. Reported mechanical data consistently show a pseudo-elastic, stress-versus-strain behavior with a linear slope after an initial "toe" region. Many studies report a linear "elastic" modulus, or Young's modulus, (hereafter called elastic modulus) and ultimate stress for their tendon specimens. Individually these studies are unable to provide a broader, inter-study understanding of tendon mechanical behavior. Herein we present a meta-analysis of pooled mechanical data from a representative sample of tendons from different species. These data include healthy tendons as well as those altered by injury and healing, genetic modification, allograft preparation, mechanical environment, and age. Fifty-one studies were selected and analyzed. Despite a wide range of mechanical properties between and within species, elastic modulus and ultimate stress are highly correlated (R 2 = 0.785) suggesting that tendon failure is highly strain-dependent. Furthermore, this relationship was seen to be predictable over controlled ranges of elastic moduli, as would be typical of any individual species. With the knowledge gained through this meta-analysis, non-invasive tools could measure elastic modulus in vivo and reasonably predict ultimate stress (or structural compromise) for diseased or injured tendon.

Deformation Pile-up/sink-in Knowledge of the elastic constants of zeolite films is of great practical interest, due to its main applications. The structural and nanomechanical properties of a faujasite-type zeolite film have been measured using nanoindentation. The hardness and elastic moduli of the film are estimated from creep and non-creep nanoindentation measurements. The deformation mechanism was analyzed using a pile-up/sink-in analysis, revealing a switch of dominant deformation mechanism at~250 nm of displacement. Wear analysis (hardness to elastic modulus ratio) provided information about the structural integrity and mechanical reliability of the film. Hardness and elastic modulus values were found to decrease with increasing penetration depth. In particular, the elastic modulus decreased from~60 GPa (at displacement of 20-30 nm) to~7 GPa (at displacement of 200 nm), and the hardness from~8 GPa (at displacement of 20-30 nm) to~0.8 GPa (at displacement of 500 nm).

Nanoindentation was used to characterize the intrinsic mechanical properties of bone tissue from eight (8) children with type III Osteogenesis Imperfecta (OI). The bone samples were harvested from the cortex portion at the site of bowing (the mid 2/3 of the shaft of the tibia/femur). Unlike normal bone tissue, OI type III cortical bone exhibited more isotropic material properties. Young's modulus and hardness values measured in the longitudinal direction did not show significant differences from the transverse measurements. No differences were observed in modulus or hardness in an analysis of the cortical and trabecular sam-ples. The deformation patterns of the OI type III bone during nanoindentation were found to be similar to those of normal adult bone in an analysis of the ratio of modulus to hardness. No correlation was found between nanoindentation measurement and age in an analysis of regression.

In this paper we examine the utility of several promising material condition monitoring (CM) techniques applied to a commercial polychloroprene cable jacketing material used in nuclear power plant applications. These include two relatively unknown approaches, cross-sectional modulus profiling and NMR T 2 relaxation time measurements of solvent-swelled samples, as well as three more commonly used approaches, density, gel fraction and solvent uptake. The results from each approach were compared to tensile elongation measurements, the usual standard approach for monitoring degradation of elastomers. Degradation was carried out at three temperatures and at four combined radiation plus thermal environments, all of which were selected (by theoretical modeling and later confirmed by cross-sectional degradation mapping) such that oxidation proceeded uniformly throughout the cross-section of the material. This allowed macroscopic condition monitoring measurements to be made in the absence of anomalous diffusion-limited oxidation effects. Of the techniques examined, modulus profiling, solvent uptake and NMR T 2 measurements correlated extremely well with the elongation measurements and therefore showed substantial potential as CM approaches for this material. This is not unexpected since all of these techniques are sensitive to crosslinking of the material and the deterioration of the elongation is itself dominated by material hardening and thus by crosslinking. Published by Elsevier Ltd.

Motivated by recent developments on calculus in metric measure spaces (X, d, m), we prove a general duality principle between Fuglede's notion of p-modulus for families of finite Borel measures in (X, d) and probability measures with barycenter in L q (X, m), with q dual exponent of p ∈ (1, ∞). We apply this general duality principle to study null sets for families of parametric and non-parametric curves in X. In the final part of the paper we provide a new proof, independent of optimal transportation, of the equivalence of notions of weak upper gradient based on p-Modulus ([21], [23]) and suitable probability measures in the space of curves ([6], [7]).

Nanocrystalline cellulose (NCC) was synthesized by the facile acid hydrolysis of Kim Wipes tissue papers and characterized with atomic force microscopy (AFM) and X-ray diffraction (XRD). AFM images confirmed the nanosize of the cellulose nanocrystals, and XRD data revealed the high crystallinity. NCCreinforced poly(vinylidene fluoride-co-hexafluoropropylene) (PH) nanocomposite films were fabricated via an electrospinning method. Different concentrations of NCC in the PH matrix were studied. The effects of the NCC content on the tensile modulus, the variation of tensile modulus with temperature, and the thermal properties of the fabricated nanocomposite films were investigated.

In this paper, we demonstrate how partial least squares multivariate analysis can be used to develop a Quantitative Structure–Activity Relationship (QSAR). The analysis is applied to the prediction of bulk modulus based on a combinatorial analysis of crystal-chemistry descriptors used in ab-initio calculations. The value of developing these QSAR formulations based on theoretical calculations is discussed in the context of its value as a screening tool for “virtual” compounds and chemistry.

Drawn polyaniline films and fibers doped with 2-acrylamido-2-methyl-propane-1-sulfonic acid, PANI(AMPS), were electrochemically cycled in HCl and their material properties and actuation performance comprehensively characterized. The Young's modulus was obtained as a function of applied voltage. Actuator figures of merit were derived from isotonic and isometric measurements, including strain, stress, work, power, creep, and efficiency. The effects of sample length, solution pH, electrochemical driving method, frequency, and load were studied, as well as the response of current to applied load for sensing applications. This work presents a complete picture of a polyaniline actuator for the first time. The behavior of the actuator is discussed in terms of the changes in the oxidation and protonation states of polyaniline.

This paper describes a study of the interaction of high pressure subcritical and supercritical carbon dioxide with a polyurethane elastomer. A novel optical high pressure cell was employed to examine the gas-polymer interactions at a molecular level, using Fourier transform infra-red spectroscopy, at 42°C and at a range of ambient pressures. Infra-red spectroscopic measurements, at atmospheric pressure, of the effect of temperature on the same polymer and a measure of the effect of temperature on the modulus on the polymer, again at atmospheric pressure, are used to estimate the effect of the absorbed gas on the modulus of the polymer.

Poly(vinyl alcohol) (PVA) composite films filled with nanometric, monodisperse, and spherical silica particles were prepared by the mixing of an aqueous PVA solution and SiO2 colloidal suspension and the evaporation of the solvent. Adjusting the solution pH to 5 and 9 controlled the PVA-SiO2 interaction. Adsorption isotherms showed a higher PVA/surface affinity at a lower pH. This interaction influenced the composite structure and the particle distribution within the polymer matrix, which was investigated by small-angle neutron scattering, electron microscopy, and swelling measurements. Most of the mechanical properties could be related to the composite structure, that is, the distribution of clusters within the polymer matrix. The progressive creation of a cluster network within the polymeric matrix as the silica volume fraction increased reduced the extensibility or swelling capacity of the composite. The effect was more acute at a higher pH, at which the surface interaction with PVA was weaker and promoted the interconnection between clusters. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 3127–3138, 2003

Chemical polymerization of pyrrole within aqueous polyvinyl alcohol (PVA) solution gives rise to a nanodispersion with unique stability and monodispersity. The nanodispersion has shown uniform distribution of perfectly spherical $110 nm polypyrrole particles (from transmission electron microscopy and dynamic light scattering) with high doping level (from UV-Vis analysis) and sufficient electrical conductivity (10 À3 S/cm). The dispersion with optimum stability and conductivity was subjected to viscoelastic studies. The viscosity of the system was adjusted by dilution with water and shear thinning (under steady shear) was generally observed. Dynamic mechanical studies have shown that the dispersion behaves like a semidiluted polymeric solution that roughly follows the Zimm model of viscoelasticity. This behavior accounts for its unique stability and miscibility with water at any proportion without precipitation. On drying or leaving the sample for 7 days, Fe 3þ induced partial crosslinking of PVA chains takes place via -OH groups, although complete gelling does not occur. The dispersion forms flexible and uniform films on glass and metal surfaces that does not dissolve after complete drying; this observation combined with shear thinning encourages its application as ink or paint. V C 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 792-800, 2011

The recycled plastics (RHDPE and RLDPE) were exposed to environment conditions for many years. Also the chemical contaminants had effects on the thermo-mechanical and other properties of these wastes. Then a weathering effect data is examined for both Iraqi and Foreign wastes on the thermo-mechanical and chemical properties (Tensile strength, modulus, elongation, impact and permeability).The different mathematical software model were applied to analysis these weathering – properties data in order to estimate which one or several among these properties had more effective by these weathering conditions such as (concentration of contaminant, time, temperature, thickness of specimen, length of spectra, basic property).

The results shows that a multi-polynomial model has a best fit for most or several of properties to active weathering variables, also gave a vary residual and deviation than experimental analyzed data for both sources of wastes Iraqi and Foreign RHDPE and RLDPE.

Also the results for thermo-mechanical and chemical properties prove that both tensile strength and modulus of elasticity thermo-mechanical properties and permeability / length of spectra chemical property were given a high quality of correction and fitting factor from 93-99 %, with less deviation and residual function was produced.
And the results of RHDPE gave a best fit than RLDPE for most of checked analysis properties (thermo-mechanical and chemical properties).

Large-scale cyclic simple shear tests were conducted on reconstituted specimens of municipal solid waste (MSW) collected from the Tri-Cities landfill in Fremont, California, USA. The influence of waste composition and compacted unit weight on the shear wave velocity, small-strain shear modulus, and straindependent shear modulus reduction and damping ratio curves of MSW was investigated in these tests. Modulus reduction and damping ratio curves were evaluated over a strain range of 0.01-3%. Specimens were reconstituted using 100%, 65%, and 35%, by weight, of the material that passed through a 20 mm screen and four different levels of compaction effort. All specimens were consolidated under a normal stress of 75 kPa prior to testing. The test results show a very strong dependence of shear wave velocity and small strain shear modulus on unit weight. Unit weight also had an influence on modulus reduction and damping ratio. Waste composition had a very strong influence on damping and also influenced shear wave velocity, small strain shear modulus, and modulus reduction. The interrelationship between unit weight and waste composition made it difficult to separate out the effects of these parameters.

A series of polypropylene (PP)-green coconut fiber (GCF) composites were prepared by melt mixing and their properties studied in the molten state using an advanced nonlinear harmonic testing technique, and in the solid state using standard mechanical testing and scanning electron microscopy (SEM). The effect of fiber loading as well as the role of maleated polypropylene as compatibilizing agent was investigated. PP-GCF composites are heterogeneous materials that, in the molten state, are found to exhibit essentially a nonlinear viscoelastic character, in contrast with the pure PP, which has a linear viscoelastic region up to 50 -60% strain. Complex modulus increases with GCF content but in such a manner that the observed reinforcement is at best of hydrodynamic origin, without any specific chemical interaction occurring between the polymer matrix and the fibers. The addition of maleated polypropylene improves the wetting of fibers by the molten polymer but the effect is so small that specific chemical reactions could hardly be considered as occurring. Flexural modulus data confirm the reinforcing effects of the fiber and an improvement is noted when some maleated polypropylene is used, with an optimum level of around 1% (or the PP content). SEM microphotographs clearly show that maleated polypropylene imparts a better wetting of GC fibers by PP, but chemical interactions are unlikely to occur between the polymer and GCF.

A method has been developed for building fully atomistic models of chemically crosslinked PVA. It combines a dynamic crosslinking approach followed by a high-temperature annealing procedure. The crosslinking procedure allows to control both crosslinking density and the amount of free crosslinking sites. It also takes into account some network defects, such as dangling tails and wasted loops, which have been experimentally observed on chemically crosslinked polymer networks. This procedure is applied to PVA which is chemically crosslinked with two different linear polyols. Several material properties such as glass transition temperature, Young's, shear and bulk modulus were predicted from the equilibrated structures and found to agree well with available experimental data.

We discuss methods to map crystallographic textures in crystal plasticity finite element simulations. Fourier-type series expansion methods which use spherical harmonic library functions as well as the direct pole figure inversion methods are not well suited to reproduce texture information in a sufficiently localized spherical form onto finite element grids. Mathematically compact Gauss-shaped spherical texture components represent a better approach for including textures in finite element models since they represent an excellent compromise between discreteness (spherical localization), compactness (simple functions), mathematical precision (very good approximation also of complex orientation distribution functions already with small sets of texture components), scalability (the number of used texture components can be systematically varied according to the desired exactness of the texture fit), conceptual simplicity (simple mathematical handling), and physical significance (texture components can be directly linked to characteristic metallurgical mechanisms). The use of texture component functions has also advantages over the use of large sets of discrete single orientations with equal scatter and height since they are more compact, practical, and provide better physical insight into microstructural mechanisms and composition sensitive effects. The article presents a new approach for the mathematical reproduction of such crystallographic texture components in crystal plasticity finite element simulations. It explains in some detail why they are particularly suited for this purpose and how they can be used to map and recover textures in/from plasticity simulations.

Dynamic mechanical thermal analysis was used to investigate the thermal transitions and modulus/temperature behavior of thermoformable carrier films, and to relate the information obtained to carrier film behavior during the thermoforming process. In this study the glass transition temperatures (T g ) and the temperatures at which crystallization occurred during heating (T c ) of four thermoformable carrier films were measured by using a dynamic mechanical thermal analyzer (DMTA). These films are good candidates for the automotive process, which uses painted carrier films as moldable automotive coatings (MAC). The modulus/ temperature behavior of the films was also observed over a wide temperature range, which included thermoforming temperatures. Although films of PETG and PCTG 5445, co-polyesters based on poly(1,4-cyclohexylene dimethylene terephthalate), are thermoformable, their T g values, 92 and 99°C, respectively, are not high enough to allow current paint systems (with bake temperature of 100-110°C) to cure on the films without causing severe film deformation.

In this work, a new approach to spherical nanoindentation analyses has been described and utilized to study the anisotropy of mechanical properties for (1 0 0) and (0 0 1) LaGaO 3 single crystals. Unlike sharp indenters, indentations by spherical indenters permit the nanoindentation load-displacement curve to be converted more reliably into indentation stress-strain curves. Using a new definition of indentation strain, we present indentation stress-strain curves that are relatively insensitive to the radii of the indenters. These curves allow the modulus of the sample to be evaluated from the elastic loading segment, instead of the common practice of approximating it from the elastic unloading segment. These measurements indicate that the (1 0 0) LaGaO 3 single crystal has a higher modulus and a higher hardness compared to the (0 0 1) sample.

Dielectric elastomers (DEs) constitute a class of electroactive polymers that are becoming increasingly important as lightweight and mechanically robust replacements for conventional transducers and actuators. Because of their inherent cycling resilience, they also show tremendous promise as energy-harvesting media, as well as smart sensors and microfluidic devices. Recent studies have demonstrated that DEs composed of midblock-solvated triblock copolymers exhibit attractive electromechanical attributes such as giant electroactuation strains at relatively low electric fields at high conversion efficiency. Moreover, the properties of these readily processable systems are highly composition-tunable, thereby making them ideal candidates for a detailed study of the cou-pling between initial specimen thickness and mechanical prestrain, which is frequently used to reduce specimen thickness before actuation to lower the voltage required to achieve electroactuation. Conventional wisdom based on the notion of an ideal DE indicates that electroactuation should only depend on pre-actuation specimen thickness, but we report results that unequivocally indicate a more detailed material/process description is required. V C 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1569-1582, 2011

Dynamic modulus of elasticity (MoE) and shear modulus of wood-filled polypropylene composite at various filler contents ranging from 10% to 50% was determined from the vibration frequencies of disc-shaped specimens. Wood filler was used in both fiber form (pulp) and powder form (wood flour). A novel compatibilizer, m-isopropenyl-␣,␣-dimethylbenzyl-isocyanate(m-TMI) grafted polypropylene with isocyanate functional group was used to prepare the composites. A linear increase in dynamic MoE, shear modulus, and density of the composite was observed with the increasing filler content. Between the two fillers, wood fiber filled composites exhibited slightly better properties. At 50% filler loading, dynamic MoE of the wood fiber filled composite was 97% higher than that of unfilled polypropylene. Halpin-Tsai model equation was used to describe the changes in the composite modulus with the increasing filler content. The continuous improvement in elastic properties of the composites with the increasing wood filler is attributed to the effective reinforcement of low-modulus polypropylene matrix with the high-modulus wood filler.

The mechanical behaviour of a new type of open-cell foam made by a thermally induced phase separation (TIPS) process was investigated. Foams made by the TIPS process are characterized by cell sizes which are 10-100 times smaller than conventional foam materials. In this work, the linear elastic modulus of these foams in dynamic tension/compression was measured. A comparison was made with the theoretical predictions and experimental data for conventional large-cell foams. Foams studied include polystyrene, poly(4-methyl-l-pentene), polyacrylonitrile and poly(7-benzyl-L-glutamate ) in the density range 0.04-0.13 g cm -3

Perovskite-structure-type sol-gel barium-strontium-titanate (BST) thin films with molar formula BaxSr1−xTiO3 (x = 0.5, 0.6, 0.7, and 0.8) have been successfully fabricated as Al/BST/Pt capacitors. In order to study the role of the grain size in the conduction mechanisms, we present atomic force microscopy (AFM) results. The impedance and the electric modulus of BaxSr1−xTiO3 thin films have been analyzed in order to correlate the effect of the film regional processes on the conduction mechanism. The impedance and the electric modulus complex planes show three overlapping regions as response for the bulk, the grain boundary and the film/electrode interface mechanisms, and an equivalent circuit has been proposed for each mechanism. The conduction mechanism resulting from the bulk and the grain boundaries is discussed; the results show that the grain boundaries have less effect on the conduction mechanism than the bulk.

Mixtures of polystyrene and high density polyethylene were injection molded from recycled and virgin polymers to generate cocontinuous structures. The mechanical properties of these blends were evaluated to assess their conformance to rule of mixtures behavior in general and to identify areas of synergy or incompatibility in specific. Flexural and tensile data for recycled blends showed that generally the properties are not additive, except in a cocontinuous region of composition near 35/65 PS/ HDPE that has been identified previously for recycled materials. Analysis of crystallinity in the HDPE phase of these blends by differential scanning calorimetry indicates a marked reduction in the level of HDPE crystallinity at the 35/65 PS/HDPE composition. Similar blends of virgin PS/ HDPE polymer do not show the differing regions of incom-patibility and synergy illustrated by the recycled materials, but rather show approximate conformance to the rule of mixtures. Furthermore, the virgin blends show virtually no crystallinity suppression and a more pronounced T g shift in the polystyrene compared to recycled materials. Detailed characterization of the recycled materials in terms of polymer and particulate impurities should improve understanding of these differences and perhaps provide direction for obtaining enhanced synergistic behavior in virgin polymer blends.

This paper describes a micromechanical analysis of the uniaxial response of composites comprising elastic platelets (bricks) bonded together with thin elastic perfectly plastic layers (mortar). The model yields closed-form results for the spatial variation of displacements in the bricks as a function of constituent properties, which can be used to calculate the effective properties of the composite, including elastic modulus, strength and work-to-failure. Regime maps are presented which indicate critical stresses for failure of the bricks and mortar as a function of constituent properties and brick architecture. The solution illustrates trade-offs between elastic modulus, strength and dissipated work that are a result of transitions between various failure mechanisms associated with brick rupture and rupture of the interfaces. Detailed scaling relationships are presented with the goal of providing material developers with a straightforward means to identify synthesis targets that balance competing mechanical behaviors and optimize material response. Ashby maps are presented to compare potential brick and mortar composites with existing materials, and identify future directions for material development.

This paper is focused on the operator inequalities of the Bohr type. We will give a new and transparent proof for the operator Bohr inequality through an absolute value operator identity, show some related operator inequalities by means of 2×22×2 (block) operator matrices, and finally we will present a generalization of the operator Bohr inequality for multiple operators.

We study an important subclass of quasicircles, namely, symmetric quasicircles. Several characterizations for quasicircles, such as the reverse triangle inequality, the M -condition and the quasiconformal extension property, have been extended to symmetric quasicircles by Becker and Pommerenke and by Gardiner and Sullivan. In this paper we establish several relations among various domain constants such as quasiextremal distance constants, (local) reflection constants and (local) extension constants for this class. We also give several characterizations for symmetric quasicircles such as the strong quadrilateral inequality and the strong extremal distance property. They correspond to the quadrilateral inequality and the extremal distance property for quasicircles.

To evaluate the efficacy on flexural properties of flowable dental resin composite reinforced with short glass fiber of different aspect ratios (ARs) and volume percent loadings. It is hypothesized that with the addition of randomly oriented fibers it is possible to significantly improve flexural strength and modulus while maintaining flowability. Ten groups of samples with varying glass fiber volume loads (0, 5%, 10%, 20%, 40% and 60%) and three different ARs (5.2, 68 and 640) were tested in three point bending to fracture according to ISO 4049. A flowable resin composite was used as the control and also as the filled resin composite that was subsequently reinforced with fibers. Load deflection results were used to calculate flexural strength and flexural modulus. SEM images were used to determine the mode(s) of failure, to describe surface features of reinforcement and were correlated with force displacement graphs. All results were statistically analysed using ANOVA followed by p...