Linear theory of nonlocal elasticity and dispersion of plane waves

The equations of the nonlocal elasticity given in [1]and[2] are linearized. The dispersion relations are obtained for one dimensional plane waves. The nonlocal material moduli are determined to fit exactly the acoustical branch of elastic waves within one Brillouin zone in periodic one dimensional lattices.     

Theories of nonlocal plasticity

Deformation and rate theories of nonlocal plasticity are formulated. Constitutive equations are obtained for elasto-plastic solids extending Lévy-von Mises and Prandtl-Reuss theories to include nonlocal effects. Combined elastic-plastic constitutive equations are given. A nonlocal deformation theory is also presented. Thermodynamical restrictions are studied.     

Electrochemical impedance study of polyaniline electrocoated porous carbon foam

Electropolymerization of aniline on mesophase pitch based carbon foam has been studied in order to evaluate the influence of conductive polymer coating on the properties of carbon foam. The surface morphology of the coating was determined by scanning electron microscopy (SEM). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical properties of resulting modified carbon foam samples. Polyaniline (PANI) electrocoated-mesophase pitch based carbon foam showed good capacitor behavior in 0.5 M H₂SO₄. Better capacitive behavior is obtained for 100 and 150 mV/s compared to other scan rates, under these faster scan rates thinner films of PANI coatings were combined with more porous structure of carbon foam. Conductivity of the carbon foam was increased from 9.23 to 13.73 S/cm by electrocoating of PANI.     

Chemical and antioxidant properties of pomegranate cultivars grown in the Mediterranean region of Turkey

Arils from six pomegranate (Punica granatum L.) cultivars obtained from various sites from the Mediterranean region of Turkey were evaluated for their chemical and antioxidant properties. These properties included total phenolics (TP), total monomeric anthocyanins (TMA), soluble solids (TSS), titratable acidity (TA), individual sugars and organic acids. Antioxidant capacities of arils were determined by both the ferric reducing antioxidant power (FRAP) and trolox equivalent antioxidant capacity (TEAC) assays. The antioxidant capacities averaged 5.60 and 7.35 mmol TE/l by the TEAC and FRAP methods. Variability among cultivars was greatest for TMA content (CV 132%); individuals ranged from 6.1 to 219 mg cy3-Gluc l⁻¹. TP means averaged 1507 mg GAE/l. Levels of FRAP, TEAC, TP, and TMA were strongly correlated (r = 0.82–0.96). The major sugars were fructose (6.4 g/100 ml) and glucose (6.8 g/100 ml), the major acids were citric (1.78 g/100 ml) and malic (0.12 g/100 ml).     

On the simultaneous description of h‐bonding and dipolar interactions with point charges in force field models

H‐bonding and polar interactions occur together in real fluids, but are of different nature and have different effects on macroscopic properties. Nevertheless, both are usually described by point charges in force field models. Despite this, the two effects can be separated. A simple model fluid is studied: a single Lennard‐Jones (LJ) site with two opposing point charges q placed in the center of the LJ site and at a distance d. By suitably varying both d and q, the dipole moment μ is kept constant. Both μ and d are systematically varied to study the properties of the resulting models, including H‐bonding, which is determined using a geometric criterion from literature. d can be used for tuning the H‐bonding strength and, thus, polarity and H‐bonding can be adjusted individually. The study of a second related model with symmetrically positioned point charges does not reveal this separation. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2926–2932, 2015     

Impact of nonlocal thin elastic plates by a cylindrical projectile

This paper is concerned with the analysis of the problem of dynamic impact of an elastic thin plate by a cylindrical projectile. The behavior of the plate material is assumed to be nonlocal elastic, and the effect of the impact is represented by a uniform velocity distribution over a circular region of the plate surface. Assuming the plate is thin, only the contributions of vertical shearing stress are considered, and the expressions of shear stress, axial displacement and the corresponding velocity components are obtained. Finally, the value of the total strain energy—crack initiation energy—for which the plastic flow will start, has been calculated and compared with experiments.     

Comparison of the impact of some Minkowski metrics on VQ/GMM based speaker recognition

This paper evaluates the impact of three special forms of the Minkowski metric (Euclidean, City Block, and Chebychev distances) on the performance of the conventional vector quantization (VQ) and Gaussian mixture model (GMM) based closed-set text-independent speaker recognition systems, in terms of recognition rate and confidence on decisions. For the VQ based system, evaluations are carried out using the two most common clustering algorithms, LBG and K-means, and it is revealed which clustering algorithm and distance pair should be used to exploit the best attribute of both to achieve the best recognition rate for a given codebook size. In the case of GMM based system, we introduce the metrics into the GMM using a concatenation of the LBG and K-means algorithms in estimating the initial mean vectors, to which the system performance is sensitive, and explore their impact on system performance. We also make comparison of results obtained from evaluations on clean speech (TIMIT) and telephone speech databases (NTIMIT and NIST2001) with the modern classifiers VQ-UBM and GMM-UBM. It is found that there are cases where conventional VQ based system outperforms the modern systems. Moreover, the impact of distance metrics on the performance of the conventional and modern systems depends on the recognition task imposed (verification/identification).     

The effect of cationic surfactant and some organic/inorganic additives on the morphology of mesostructured silica templated by pluronics

Tri-block copolymers (poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide), represented as EO_xPO_yEO_x), pluronics (F127 = EO₁₀₆PO₇₀EO₁₀₆, P65 = EO₂₀PO₃₀EO₂₀, P85 = EO₂₇PO₃₉EO₂₇, P103 = EO₁₇PO₅₅EO₁₇, and P123 = EO₂₀PO₇₀EO₂₀) and cationic surfactants (cethyltrimethylammonium bromide (CTAB)), two surfactant systems, form complex micelles that self-assemble into mesostructured particles with distinct morphology depending on the pluronic type, the concentration of the cationic surfactant and the organic–inorganic ingredients in a siliceous reaction media under acidic conditions. The CTAB–P65 and CTAB–P85 systems form spheres, CTAB–P103 and CTAB–P123 systems form wormlike particles, and CTAB–F127 system form single crystals of mesostructured silica particles under very similar conditions. However addition of various salts (such as KCl and NaNO₃) into a CTAB–P103 or CTAB–P123 solution system and cyclohexane and KCl into a CTAB–P85 solution system produces the mesostructured silica spheres and wormlike particles, respectively. By controlling the hydrophilic–hydrophobic character of the pluronics, core–corona interface, by means of additives, such as small organic molecules or salts, one could obtain the desired morphology that is dictated by the shape of the micelles of the pluronic–cationic surfactant complex. The effects of the additives and the formation mechanism of those morphologies have been discussed using spectroscopy (FT-IR and Raman), diffraction (XRD) and microscopy (POM and SEM) data.