Dynamic stability of uncertain laminated beams subjected to subtangential loads

Because of the inherent complexity of fiber-reinforced laminated composites, it can be challenging to manufacture composite structures according to their exact design specifications, resulting in unwanted material and geometric uncertainties. Thus the understanding of the effect of uncertainties in laminated structures on their static and dynamic responses is highly important for a reliable design of such structures. In this research, we focus on the probabilistic stability analysis of laminated structures subject to subtangential loading, a combination of conservative and nonconservative tangential loads, using the dynamic criterion. In order to study the dynamic behavior by including uncertainties into the problem, three models were developed: exact Monte Carlo simulation, sensitivity-based Monte Carlo simulation, and probabilistic FEA. These methods were integrated into the existing finite element analysis. Also, perturbation and sensitivity analysis have been used to study nonconservative problems to study the stability analysis using the dynamic criterion.     

New sources of “active” halogen bis(dialkylamide)hydrogen dibromobromates, efficient reagents for destruction of ecotoxicants

Bis(dialkylamide)hydrogen dibromobromates were synthesized and their reactivity was investigated in decomposition of diethylphosphonic, diethylphosphoric, and 4-toluenesulfonic acids 4-nitrophenyl esters. The nucleophilic reactivity of a typical α-nucleophile, hypobromite ion, is independent of the source of the active bromine. The cetyltrimethylammonium dibromobromate is a unique reagent for destruction of ecotoxicants. In weakly alkaline media the half-life of 4-nitrophenyl diethylphosphonate did not exceed 6 s at [BrO^?] 0.02 mol l^?1, and the apparent reaction rate compared to water increased ～40-fold. The main factor governing the micellar effects of surfactants is concentrating the substrate in the micellar pseudophase.     

Globally anisotropic high porosity silica aerogels

We discuss two methods by which high porosity silica aerogels can be engineered to exhibit global anisotropy. First, anisotropy can be introduced with axial strain (i.e. axial compression). In addition, intrinsic anisotropy can result during growth and drying stages and, suitably controlled, it can be correlated with preferential radial shrinkage in cylindrical samples. We have performed small angle X-ray scattering (SAXS) to characterize these two types of anisotropy. We show that global anisotropy originating from either strain or shrinkage leads to optical birefringence and that optical cross-polarization studies are a useful characterization of the uniformity of the imposed global anisotropy.     

Nucleophilic addition to acetylenes in superbasic catalytic systems: XV. Vinylation of 2-hydroxymethylfuran

2-Hydroxymethylfuran reacted with acetylene in superbasic catalytic systems MOH-DMSO (M = Na, K) under mild temperature conditions (75–85°C, 1–2 h), yielding 80% of 2-vinyloxymethylfuran. The product, as well as acetaldehyde acetals derived therefrom, turned out to be promising as modifiers for electrolyte in lithium-sulfur rechargeable batteries.     

Imaginary entanglement as a cost of unitarity

The contradiction between the fidelity necessary to determine the entanglement of states and the noise accompanying high-precision measurements is discussed. The unitary nonequivalence of quantum field representations in different regions of space leads to an additional noise, analogously to the Unruh effect. The cause of this noise is eliminated by rejecting the assumption of statistical independence of single-particle states of the quantum field. The smearing of one-particle states eliminates the reasons for the appearance of the Unruh noise and, simultaneously, leads to imaginary entanglement due to overlapping of these states.     

On the Development of Fundamentally New Organic Reagents

Based on an analysis of the processes of intramolecular signal transfer (the ordered motion of a quasiparticle, vibron) and structural isomerization, it was pointed out that, in principle, reagents of a new type can be developed with analytical effects fundamentally different from usual ones. The type of analytical response can vary depending on the molecular structure and intramolecular processes induced. General principles of the molecular design of systems of this kind are discussed.     

On the Bol Loops

In the present paper, the Bol loops and related groups are studied. We suggest a universal way to construct a Bol loop and find criteria for simplicity and finiteness of such loops.     

Coprecipitation of Naphthol Azosulfonates with Organic Coprecipitants and Its Use in Flow-Injection Analysis

The coprecipitation of azo compounds based on 4-nitrophenyl- and 4-sulfophenyldiazonium naphthol sulfonates as their diphenylguanidinium ion-pair complexes with analogous compounds of naphthalene-2-sulfonic acid and 4-phenylsulfodiazonium is investigated. The optimization of the coprecipitation is considered based on the notions of the driving force of the cocrystallization of impurities. The optical characteristics of colored ion-pair complexes are measured. It is found that the water solubility is decreased most substantially for azosulfonates with hydrophobic nitro groups and with no more than two sulfo groups in different aromatic nuclei, which can lead to a decrease in the detection limit due to preconcentration by coprecipitation, which stimulates the thermodynamic flux of concentrate elution. Coprecipitation is combined with flow-injection analysis in the on-line mode, and new procedures are developed for determining naphthol sulfonates and related azo compounds with the detection limit equal to 0.003–0.006 mg/50 mL.     

Crystallographic report: Crystal structure of 1‐bromo‐1′‐[(2S)‐N‐(1‐hydroxy‐3‐methylbutane‐2‐yl)]‐ferroceneamide

For the unsymmetrical title compound, 1‐bromo‐1′‐[(2S)‐N‐(1‐hydroxy‐3‐methylbutane‐2‐yl)]‐ferroceneamide, two independent molecules were found in the asymmetric unit. Copyright © 2003 John Wiley & Sons, Ltd.