Extension of an algorithm for product mix problems with fuzzy conditions

In the real world of production, there are some uncertain parameters such as capacity, profit, and processing time. On the other hand, the fuzzy sets theory is applied as a suitable tool for managing production where dynamicity of the production environment prevents from determining target function, constraints and other parameters of the model. In this paper, a genetic algorithm embedded in fuzzy revised theory of constraints is presented for product mix problems. Results of implementing the proposed algorithm show efficiency and flexibility of this algorithm.     

Direct, one-step synthesis of condensed heterocycles: a palladium-catalyzed coupling approach

[reaction: see text] A palladium-catalyzed one-step synthesis of fused aromatic heterocycles from bifunctional bromoenoates or bromoalkyl indoles and iodoarenes is reported. This method provides an efficient route to a wide variety of substituted polycyclic aromatic and heteroaromatic compounds from readily accessible starting materials.     

On Fuzzy Preordered Structures and （Fuzzy） Hyperstructures

This article presents a connection between fuzzy preordered structures and hyperstructures. Firstly, we introduce the notion of fuzzy preordered semigroup and then, we construct a semihypergroup associated with it, giving some properties of the associated hyperstructure. Secondly, we define the notion of fuzzy preordered ring in order to construct a fuzzy hyperring.     

ZrCl4 dispersed on dry silica gel provides a useful reagent for S-alkylation of thiols with alcohols under solvent-free conditions

ZrCl₄ which is commercially available and not a costly compound, is a relatively safe chemical [LD₅₀ [ZrCl₄, oral rat] = 1688 mg Kg]. In this report we describe the use of ZrCl₄ dispersed on dry silica gel as an efficient reagent for the efficient preparation of thioethers from thiols with alcohols under solvent-free conditions.     

A simple, efficient, and highly selective method for the iodination of alcohols using ZrCl4/NaI

Iodination of primary, secondary, allylic, and benzylic alcohols giving their corresponding iodides was achieved with ZrCl₄/NaI in anhydrous CH₃CN with excellent yields and selectivities.     

Molecular mobility of poplar cell wall polymers studied by dielectric techniques

In this work, thermally stimulated currents (TSC) analyzes combined with dynamic dielectric spectroscopy (DDS) have been applied to the investigation of polymers’ molecular mobility involves in poplar cell wall. The molecular origin of the various dielectric relaxations has been determined. Cellulose and lignin effects in wood dielectric response were distinguished. The correlation between results obtained by both dielectric methods allows us to follow molecular mobility involved in delocalized movement as primary relaxation mode. For these two major components of wood, the evolution of relaxation times involve in α-relaxation mode is explained using the strong/fragile pattern. We compared the cellulose and lignin in situ and ex situ responses to interpret wood compound behavior. The importance of structural wood interactions which modified the molecular mobility of polymer components will be underlined.     

Octic Anharmonic Oscillators: Perturbed Coherent States and the Classical Limit

We use the Poincaré-Linstedt method to find a classical perturbation solution to the octic anharmonic oscillator. Next, we derive perturbed coherent states for this system, calculate the expectation value of the -operator in them and enforce a limiting process to retrieve the classical result from the corresponding quantum one. We have observed a frequency shift proportional to the sixth power of the amplitude for this system. Our results are in agreement with those obtained from Taylor-series method.     

Thermal Spin Squeezing as a Signature of Thermal Global Entanglement in Heisenberg Models

We study thermal spin squeezing (TSS) and thermal global entanglement (TGE) in a general Heisenberg spin chain, in the presence of Dzyaloshinskii-Moriya interaction and an external magnetic field. We derive an inequality associating the squeezing parameter and the global concurrence, which establishes (TSS) as a signature of (TGE). The inequality reduces to equality for particular symmetric chains which also associates TSS with bipartite entanglement in such systems. We also check the results by presenting two numerical examples.     

Conformational analysis of 2‐alkyl‐4‐methyl‐2,6‐diphenyl‐2H‐thiopyran derivatives: A combined experimental and theoretical study

Some 2‐alkyl‐4‐methyl‐2,6‐diphenyl‐2H‐thiopyrans were synthesized, and the crystal structure of 2‐tert‐butyl‐4‐methyl‐2,6‐diphenyl‐2H‐thiopyran 1 was determined by single‐crystal X‐ray diffraction. X‐ray crystallographic analysis and ab initio HF/6‐31G(d) and B3LYP/6‐31G(d) calculations revealed a favorable nonplanar half‐chair conformation for these compounds in which two ethylene units were rotated relative to each other around the single bond. The most conspicuous feature was the orientation of alkyl and phenyl groups with respect to the S atom. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:142–147, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20192     

Large-bandwidth ultra-low-loss guiding in bi-periodic photonic crystal waveguides

For the first time, we experimentally demonstrate ultra-low-loss guiding in bi-periodic photonic crystal waveguides over a large bandwidth of more than 60 nm. In such bi-periodic waveguides, we achieve a propagation loss very similar to that of a dielectric ridge waveguide, which indicates that the dominant loss mechanism in these bi-periodic waveguides is due to fabrication imperfections. PACS 42.70.Qs; 42.79.Gn