this study presents the synthesis of polyvinyl acetate (pvac) by solution polymerization and its partial hydrolysis to polyvinyl alcohol (pva) using alkaline alcoholysis. the influence of the molar ratio of hydrolysis catalyst (naoh) to pvac and the time and temperature of the saponification reaction on the degree of hydrolysis and molecular weight of the pva were investigated using response su...

background: similar to the thermoluminescence (tl) spectra, the optical parameters variations can also be used in tl crystals for dosimetry purposes. these optical parameters can include absorption, transmission and reflection coefficients. materials and methods: single crystals of kbr and kcl which have been used in this research were grown from laboratory grade extra pure precursor powders. c...

We report infrared photodissociation (IRPD) spectra for the D2-tagged titanium oxide cluster anions (TiO2)n(-) with n = 3-8 in the spectral region from 450 to 1200 cm(-1). The IRPD spectra are interpreted with the aid of harmonic spectra from BP86/6-311+G* density functional theory calculations of energetically low-lying isomers. We conclusively assign the IRPD spectra of the n = 3 and n = 6 cl...

The response of structures bonded to the surface of a transversely isotropic half-space (TIHS) under the effect of time-harmonic forces is investigated using a coupled FE-BE scheme. To achieve this end, a Finite Element program has been developed for frequency domain analysis of 3D structures, as the first step. The half-space underlying the structure is taken into consideration using a Boundar...

The behavior of complex interfacial systems is central to an ever-increasing number of applications. Vibrational sum frequency (VSF) spectroscopy is a powerful technique for obtaining surface specific structural information. The coherent nature of VSF that provides surface specificity, however, also creates difficulty in spectral interpretation especially as the system complexity increases. Com...

The magneto-optical properties of cesium vapor near a glass surface have been studied by using selective reflection. We have observed sub-Doppler structures in the magnetorotation and magnetic circular dichroism spectra. The spectral narrowing can be explained by the transient polarization behavior of cesium atoms due to wall collisions. A simple model, which takes atom-wall collisions and the ...

Let Z + = Z d × Z+, let H0 be the discrete Laplacian on the Hilbert space l2(Z + ) with a Dirichlet boundary condition, and let V be a potential supported on the boundary ∂Z + . We introduce the notions of surface states and surface spectrum of the operator H = H0 + V and explore their properties. Our main result is that if the potential V is random and if the disorder is either large or small ...

 The uses of non-steroidal anti-inflammatory drugs (NSAIDs) are limited by a variety of side effects. So research on preparing new analgesic agents is important. According to some reports about the analgesic activity of hydrazide and hydrazine derivatives a new series of these compounds were synthesized in order to obtain new analgesic compounds. The final compounds 10a-10e and 15a-15d were pre...

In this article, we tried to emphasis in how the range of torsionally stiff and flexible single story buildings works. The designed base was according to provisions of the Canadian standard, 2005 NBCC. The behavior of nonlinear dynamic time history of eight building models subjected to seven horizontal bi-directional ground motions compatible with design spectra are investigated. These models c...