The direct and inverse theorems are established for the best approximation in the weighted L space on the unit sphere of R, in which the weight functions are invariant under finite reflection groups. The theorems are stated using a modulus of smoothness of higher order, which is proved to be equivalent to a K-functional defined using the power of the spherical h-Laplacian. Furthermore, similar ...

This paper investigates the effective wall thickness of a single-walled carbon nanotube, a critical quantity for any research in mechanics and property characterization of carbon nanotubes. To this end, the response of a bundle of single-walled carbon nanotubes to external hydrostatic pressure was modeled using the ring theory of continuum mechanics. The model predicted that the equivalent thic...

We show that the exact beta–function of 4D N = 2 SYM plays the role of the inverse of the metric in the WDVV–like equations F ikl β lm F mnj = F jkl β lm F mni. The conjecture that the WDVV–like equations are equivalent to the identity between the u–modulus and the prepotential F , seen as a superconformal anomaly, sheds light on the recently considered C–theorem for the N = 2 SYM field theories.

the rheological properties of four different kuwaiti crude oils in the presence of polyacrylamide (paa) were investigated. paa was varied at three different concentrations of 25, 50, and 75 ppm to study the viscoelastic properties in the untreated samples. four different temperatures (25, 30, 35, and 40 °c) were used to evaluate different viscoelastic parameters of the treated and untreated kuw...

In this study, a technique has been proposed for developing constitutive models for polymer composite systems reinforced with single-walled carbon nanotubes (SWNT) with various orientations with respect to the bulkmaterial coordinates. A nanotube, the local polymer adjacent to the nanotube, and the nanotube/polymer interface have been modeled as an equivalent-continuum fiber by using an equival...

Surface probe measurements of the elasticity of thin-film matrices as well as biological samples prove generally important to understanding cell attachment across such systems. To illustrate this, sectioned arteries were probed by Atomic Force Microscopy (AFM) within the smooth muscle cell (SMC)-rich medial layer, yielding an apparent Young’s modulus Emedia ~ 5-8 kPa. Polyacrylamide gels with E...

With the aim of introducing permanent prostheses with main properties equivalent to cortical human bone, Ti-diamond composites were processed through powder metallurgy. Grade 1 titanium and mixtures of Ti powder with 2%, 5% and 10 wt% diamond were compacted at 100MPa, and then sintered at 1250°C/2hr/10-6mbar. Sintered samples were studied in the point of view of their microstructures, structure...

In this research, the influence of structure on the tensile properties of single- walled carbon nanotubes (CNTs) is evaluated using molecular mechanics technique and finite element method. The effects of diameter, length and chiral angle on elastic modulus and Poisson’s ratio of armchair, zigzag and chiral structures are investigated. To simulate the CNTs, a 3D FEM code is developed using the A...

1. Let G and G' be two plane open sets and w(z) a topological map.ping of G onto G'. By Q we denote any quadrilateral in G, i.e. the topological image of a closed square with a distinguished pair of opposite sides. The conformal modulus m of Q is the ratio m=a/b of the sides of a conformally equivalent rectangle 22, the distinguished sides of Q corresponding to the sides of length b. We call th...

Single-crystal tungsten nanobelts with thicknesses from tens to hundreds of nanometers, widths of several micrometers and lengths of tens of micrometers were synthesized using chemical vapor deposition. Surface energy minimization was believed to have played a crucial role in the growth of the synthesized nanobelts enclosed by the low-energy {110} crystal planes of body-centered-cubic structure...