Cosmological Relativity: A New Theory ofCosmology1

A new general-relativistic theory of cosmology, the dynamical variables of whichare those of Hubble's, namely distances and redshifts, is presented. The theorydescribes the universe as having a three-phase evolution with a deceleratingexpansion followed by a constant and an accelerating expansion, and it predictsthat the universe is now in the latter phase. The theory is actually a generalizationof Hubble's law taking gravity into account by means of Einstein's theory ofgeneral relativity. The equations obtained for the universe expansion are elegantand very simple. It is shown, assuming ₀ = 0.24, that the time at which theuniverse goes over from a decelerating to an accelerating expansion, i.e., theconstant expansion phase, occurs at 0.03 from the big bang, where is theHubble time in vacuum. Also, at that time the cosmic radiation temperature was11 K. Recent observations of distant supernovae imply, in defiance of expectations,that the universe's growth is accelerating, contrary to what has always beenassumed, that the expansion is slowing down due to gravity. Our theory confirmsthese recent experimental results by showing that the universe now is definitelyin a stage of accelerating expansion.     

On stochastic spatial patterns and neuronal polarity

To investigate the statistical behavior in the sizes of finite clusters for percolation, cluster size distribution n _s (p) for site and bond percolations at different lattices and dimensions was simulated using a modified algorithm. An equation to approximate the finite cluster size distribution n _s (p) was obtained and expressed as: log?(n _s (p)) = as ? b log?s + c. Based on the analysis of simulation data, we found that the equation is valid for p from 0 to 1 on site and for the bond percolation of two-dimensional (2D) and three-dimensional (3D) lattices. Furthermore, the relationship between the coefficients of the equation and the occupied ratio p was studied using the finite-size scaling method. When \(x = D(p - p_c )L^{y_t }\) , p < p _c , and D was a nonuniversal metric factor. a was found to be related only to p, and the a-x curves of different lattices were nearly overlapped; b was related to the dimensions and p, and the scaled data of the b of all lattices with the same dimension tended to fall on the same curves. Unlike a and b, c apparently had a quadratic relation with x in 2D lattices and linear relation with x in 3D lattices. The results of this paper could significantly reduce the amount of tasks required to obtain numerical data of on the cluster size distribution for p from 0 to p _c .     

Diode laser spectroscopy of the ν7a band of fluorobenzene

The diode laser absorption infrared spectrum of fluorobenzene has been recorded near 1230 cm⁻¹ after cooling the molecules in a supersonic pulsed jet. Spectral lines have been assigned to the ν_7a fundamental band. Transitions of J between 32 and 49 have been recorded, that show characteristic line groupings in the P branch. Analysis of the spectrum gives the vibrational band origin and rotational and centrifugal distortion constants of the molecule in the ν_7a = 1 state.     

Chemical modification of chitosan under high-intensity ultrasound

Chitosan (CTS), a biocompatible, biodegradable, non-toxic polymer, dissolves in water only if pH is lowered under 6.5, when a substantial fraction of the amino groups is protonated. Its range of application has been much extended by partially depolymerising it or converting it to water-soluble derivatives. Working under high-intensity ultrasound at 17.8-18.5 kHz, using either a simple horn or a cup horn, we achieved a controlled depolymerization of CTS, also prepared in high yields several derivatives that can be useful intermediates for further chemical modification, as well as several water-soluble derivatives that lend themselves to a host of industrial applications. Compared to conventional methods, all these reactions went to completion in considerably shorter times at lower temperatures.     

Online re-optimization of optical filters on a production sputter tool

This contribution presents a magnetron sputter deposition tool with broadband optical monitor and online re-optimization capability for high volume production. The layer termination relies on a comparison of the actually measured reflection spectrum with a pre-calculated target spectrum. Spectra recorded after each deposited layer are analyzed by the re-optimization module and in case of significant deviations layer thicknesses and target spectra for the remaining layers are recalculated. This technique significantly improves the performance and reproducibility in case of highly denlanding coating designs and is able to correct abnormal production errors in individual layers, which will lead to coating failure without re- optimization.     

Synthesis of carbon nanotubes by CVD: Effect of acetylene pressure on nanotubes characteristics

The effect of acetylene partial pressure on the structural and morphological properties of multi-walled carbon nanotubes (MWCNTs) synthesized by CVD on iron nanoparticles dispersed in a SiO₂ matrix as catalyst was investigated. The general growing conditions were: 110 cm³/min flow rate, 690 °C synthesis temperature, 180 Torr over pressure and two gas compositions: 2.5% and 10% C₂H₂/N₂. The catalyst and nanotubes were characterized by HR-TEM, SEM and DRX. TGA and DTA were also carried out to study degradation stages of synthesized CNTs. MWCNTs synthesized with low acetylene concentration are more regular and with a lower amount of amorphous carbon than those synthesized with a high concentration. During the synthesis of CNTs, amorphous carbon nanoparticles nucleate on the external wall of the nanotubes. At high acetylene concentration carbon nanoparticles grow, covering all CNTs’ surface, forming a compact coating. The combination of CNTs with this coating of amorphous carbon nanoparticles lead to a material with high decomposition temperature.     

Imaging spin-reorientation transitions in consecutive atomic Co layers on Ru(0001)

By means of spin-polarized low-energy electron microscopy, we show that the magnetic easy axis of one to three atomic-layer thick cobalt films on Ru(0001) changes its orientation twice during deposition: One-monolayer and three-monolayer thick films are magnetized in plane, while two-monolayer films are magnetized out of plane. The Curie temperatures of films thicker than one monolayer are well above room temperature. Fully relativistic calculations based on the screened Korringa-Kohn-Rostoker method demonstrate that only for two-monolayer cobalt films does the interplay between strain, surface, and interface effects lead to perpendicular magnetization.     

Shear band formation and ductility in bulk metallic glass

The variations in the chemical compositions of the metallic glasses reported in the literature, as well as the overall lack of experimental data concerning the inhomogeneous deformation behaviour of metallic glass, make the evaluation of the effects of shear band/fracture behaviour on the mechanical properties of metallic glasses difficult. Isolating the effect of local shear band formation on bulk inhomogeneous flow would appear to be a first step in approaching this problem. The mechanical behaviour of Vitreloy metallic glass at room temperature and at various strain rates in tension and compression was investigated. The formation of multiple shear bands was observed at high strain rates. An increase in strain rate leads to enhanced ductility in tension and compression. Some aspects of the deformation processes in tension and compression are discussed.     

A longitudinal study of MR diffusion changes in normal appearing white matter of patients with early multiple sclerosis

BACKGROUND AND PURPOSE: The stage at which normal appearing white matter (NAWM) abnormalities first appear in multiple sclerosis (MS) is not clear. The aim of our study was to monitor water diffusion changes over time in NAWM of patients with early MS.METHODS: Out of a consecutive series of patients enrolled in a MR study on clinically isolated syndrome (CIS), we selected 19 subjects who had completed a one year follow-up. The MR scans obtained at baseline and at 12 months were reviewed according to the new criteria on the diagnosis of MS. Lesion load on T2 and T1 weighted images and the trace of the apparent diffusion coefficient in NAWM were measured both at baseline and at 12 months in patients and in 12 healthy controls.RESULTS: In three patients the diagnosis of MS was done at baseline based on MR. Thirteen patients developed MS during the study and in three patients the diagnosis remained "possible MS." TADC in NAWM in patients was significantly higher than in controls at the 12 months' follow-up but not at baseline (controls mean tADC +/- sd = 0.745 +/- 0.02 mm(2)/sec x 10(-3); patients mean tADC(12) +/- sd = 0.767 +/- 0.02 mm(2)/sec x 10(-3); p < 0.02). TADC and T2 lesion load at 12 months were significantly correlated (p < 0.01). Patients exhibiting tADC(12) above a confidence interval had a significantly greater EDSS score at the same time period (EDSS(12) +/- sd = 1.9 +/- 0.5 and = 1.1 +/- 0.4 respectively; p < 0.01).CONCLUSIONS: This study suggests that diffusion MR cannot detect alterations in NAWM of patients with a CIS suggestive of MS. After one year, when most patients develop MS, diffusion MR abnormalities in NAWM become apparent. These abnormalities are correlated with T2 lesion load and may contribute to neurological impairment.