Microporous La–Metal–Organic Framework (MOF) with Large Surface Area

A microporous La–metal‐organic framework (MOF) has been synthesized by the reaction of La(NO₃)₃ ? 6 H₂O with a ligand 4,4′,4′′‐s‐triazine‐1,3,5‐triyltri‐p‐aminobenzoate (TATAB) featuring three carboxylate groups. Crystal structure analysis confirms the formation of 3D MOF with hexagonal micropores, a Brunauer–Emmett—Teller (BET) surface area of 1074 m² g^?1 and high thermal and chemical stability. The CO₂ adsorption capacities are 76.8 cm³ g^?1 at 273 K and 34.6 cm³ g^?1 at 293 K, a highest measured CO₂ uptake for a Ln–MOFs.     

A stratified Monte Carlo simulation of CSD in a continuous crystallizer for size-dependent growth

This work deals with the prediction of crystal size distribution (CSD) in a continuous crystallizer for size-dependent growth. Crystal growth rates are described by Abegg, Stevens, and Larson (ASL) model. Stratified Monte Carlo method has been employed to evaluate the integrals involved in the classical moment equation for prediction of CSD. The simulation results have been compared with the available experimental data of K₂CO₃ · 1.5 H₂O crystals in a continuous crystall lizer.     

Design of peptides with α,β-de­hydro residues: a dipeptide with a branched β-carbon de­hydro residue at the (i+1) position,methyl N-(benzyloxycarbonyl)-α,β-dide­hydro­valyl-l-tryptophanate

The structure of the title peptide, C₂₅H₂₇N₃O₅, has been determined and its conformation analysed. Values of the standard peptide torsion angles are ϕ₁ = −44.2 (3)°, ψ₁ = 135.9 (2)°, ϕ₂ = −141.6 (2)° and ψ₂^T = 168.0 (2)°. The crystal structure is stabilized by an intermolecular hydrogen bond, with an N⃛O distance of 2.919 (3) Å, which is formed between screw-axis-related NH and CO groups of de­hydro­valine residues.     

Characteristic Functions for Ergodic Tuples

Motivated by a result on weak Markov dilations, we define a notion of characteristic function for ergodic and coisometric row contractions with a one-dimensional invariant subspace for the adjoints. This extends a definition given by G. Popescu. We prove that our characteristic function is a complete unitary invariant for such tuples and show how it can be computed.     

Two dimensional lattice-free cuts and asymmetric disjunctions for mixed-integer polyhedra

In this paper, we study the relationship between 2D lattice-free cuts, the family of cuts obtained by taking two-row relaxations of a mixed-integer program (MIP) and applying intersection cuts based on maximal lattice-free sets in ${\mathbb{R}^2}$ , and various types of disjunctions. Recently Li and Richard (2008), studied disjunctive cuts obtained from t-branch split disjunctions of mixed-integer sets (these cuts generalize split cuts). Balas (Presentation at the Spring Meeting of the American Mathematical Society (Western Section), San Francisco, 2009) initiated the study of cuts for the two-row continuous group relaxation obtained from 2-branch split disjunctions. We study these cuts (and call them cross cuts) for the two-row continuous group relaxation, and for general MIPs. We also consider cuts obtained from asymmetric 2-branch disjunctions which we call crooked cross cuts. For the two-row continuous group relaxation, we show that unimodular cross cuts (the coefficients of the two split inequalities form a unimodular matrix) are equivalent to the cuts obtained from maximal lattice-free sets other than type 3 triangles. We also prove that all 2D lattice-free cuts and their S-free extensions are crooked cross cuts. For general mixed integer sets, we show that crooked cross cuts can be generated from a structured three-row relaxation. Finally, we show that for the corner relaxation of an MIP, every crooked cross cut is a 2D lattice-free cut.     

Multi-criteria decision making approaches for supplier evaluation and selection: A literature review

Supplier evaluation and selection problem has been studied extensively. Various decision making approaches have been proposed to tackle the problem. In contemporary supply chain management, the performance of potential suppliers is evaluated against multiple criteria rather than considering a single factor-cost. This paper reviews the literature of the multi-criteria decision making approaches for supplier evaluation and selection. Related articles appearing in the international journals from 2000 to 2008 are gathered and analyzed so that the following three questions can be answered: (i) Which approaches were prevalently applied? (ii) Which evaluating criteria were paid more attention to? (iii) Is there any inadequacy of the approaches? Based on the inadequacy, if any, some improvements and possible future work are recommended. This research not only provides evidence that the multi-criteria decision making approaches are better than the traditional cost-based approach, but also aids the researchers and decision makers in applying the approaches effectively.     

Endothermic quasicrystalline-to-crystalline phase transition in Al6CuMg4

Electron microscopic and differential scanning calorimetric (DSC) studies have been performed to investigate the phase transitions in the rapidly solidified Al₆CuMg₄ alloy system. We present evidence, for the first time, that anendothermic quasicrystalline to crystalline transition occurs in this system around 340°C. This is an unexpected feature—for conventional wisdom would lead one to expect exothermic behaviour as was seen in Al₈₆Mn₁₄—and points to the fact that stability of certain quasicrystalline phases may be much larger than hitherto expected. Some comments on the recently reported large quasicrystal for the Al₆CuLi₃ system are also made in the light of our observation.     

Synthesis of multi-wall carbon nanotubes by simple pyrolysis

A new pyrolysis technique has been developed for the synthesis of multi-walled carbon nanotubes (MWCNTs). In this simple method diethyl ether and nickelocene is pyrolysized in a reaction quartz tube without using carrier gas. The samples are prepared at pyrolysis temperatures of 650 and 950 ^°C and the effect of temperature on the tube morphology investigated. Purification has been done following the standard oxidation and acid bath treatment. The as-synthesized and purified nanotubes have been characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), transmission electron microscope (TEM), thermogravimetric analysis (TGA) and micro-Raman spectroscopy. The technique has great advantages such as low cost and easy operation for the production of CNTs.     

Defect detection and localization in orthotropic wood slabs by inversion of dynamic surface displacements

The nondestructive evaluation inversion and generalized force-mapping techniques developed and demonstrated for isotropic thin plates by Bucaro et al. [(2004). "Detection and localization of inclusions in plates using inversion of point actuated surface displacements," J. Acoust. Soc. Am. 115, 201-206] are extended to the case of orthotropic plates. The extended techniques are applied to a finite-element generated numerical database for point excited wooden slabs with and without an internal defect at 5 and 10 kHz. Operation of the original isotropic algorithms on the wood surface displacements is shown to fail in recovering the uniform elastic parameters or in detecting and locating the defect. The new algorithms based on the wave equation for a thin, orthotropic plate successfully convert the surface displacements on the uniform wooden slab to elastic parameter maps which serve to detect and localize the defect in the flawed plate. The results, particularly at the higher frequency, indicate that the onset of failure in the thin plate approximation impacts both the inversion and the generalized force-mapping accuracy. However, in this case use of the inversion algorithm to obtain modified wave equation coefficients followed by operation of the force-mapping algorithm with these new parameters inserted is shown to successfully mitigate this effect.