Magnetic Properties of Pt-Based Nanoalloys: A Critical Review

In recent years, magnetic nanoalloys (MNAs) have attracted many attentions from all over the world, due to their potential applications in the broad fields of magneto-optics, data storage, engineering, and biology. Among these MNAs, Pt–M (M = Fe, Co, Ni) MNAs have been considered to be the most promising ones, due to their superparamagnetism and response to a magnetic field. Here, we firstly review the experimental work on the synthesis, characterization, and magnetic properties of Pt–Fe, Pt–Co, and Pt–Ni MNAs. Then, we discuss the recent theoretical work on Pt–Fe, Pt–Co, and Pt–Ni MNAs. Moreover, we also review the main applications of Pt–Fe, Pt–Co, and Pt–Ni MNAs in the fields of biology, information storage, and magnetic separation. It is found that the size, shape, and composition of Pt–Fe, Pt–Co, and Pt–Ni MNAs play a critical role on their fundamental magnetic properties from both the experimental and theoretical points of view. It is expected that this review could be a valuable resource for both experimental and theoretical researchers, who are interested in Pt-based MNAs.     

Prediction of intracellular storage polymers using quantitative image analysis in enhanced biological phosphorus removal systems

The present study focuses on predicting the concentration of intracellular storage polymers in enhanced biological phosphorus removal (EBPR) systems. For that purpose, quantitative image analysis techniques were developed for determining the intracellular concentrations of PHA (PHB and PHV) with Nile blue and glycogen with aniline blue staining. Partial least squares (PLS) were used to predict the standard analytical values of these polymers by the proposed methodology. Identification of the aerobic and anaerobic stages proved to be crucial for improving the assessment of PHA, PHB and PHV intracellular concentrations. Current Nile blue based methodology can be seen as a feasible starting point for further enhancement. Glycogen detection based on the developed aniline blue staining methodology combined with the image analysis data proved to be a promising technique, toward the elimination of the need for analytical off-line measurements.     

Toward low‐noise synthetic turbulent inflow conditions for aeroacoustic calculations

The accuracy of boundary conditions for computational aeroacoustics is a well‐known challenge, due in part to the necessity of truncating the flow domain and replacing the analytical boundary conditions at infinity with numerical boundary conditions. In particular, the inflow boundary condition involving turbulent velocity or scalar fields is likely to introduce spurious waves into the domain, therefore degrading the flow behavior and deteriorating the physical acoustic waves. In this work, a method to generate low‐noise, divergence‐free, synthetic turbulence for inflow boundary conditions is proposed. It relies on the classical view of turbulence as a superposition of random eddies convected with the mean flow. Within the proposed model, the vector potential and the requirement that the individual eddies must satisfy the linearized momentum equations about the mean flow are used. The model is tested using isolated eddies convected through the inflow boundary and an experimental benchmark data for spatially decaying isotropic turbulence. Copyright © 2013 John Wiley & Sons, Ltd.     

Tuning the mesogenic properties of 5-alkoxy-2-(4-alkoxyphenyl)pyrimidine liquid crystals: the effect of a phenoxy end-group in two sterically equivalent series

Two sterically equivalent series of phenoxy-terminated 5-alkoxy-2-(4-alkoxyphenyl)pyrimidine liquid crystals were synthesised, and their mesogenic properties were characterised by polarised optical microscopy and differential scanning calorimetry (DSC). The phenoxy end-group causes a significant increase in melting point and inhibits – at least partially – the mesomorphism of these materials relative to the parent isomers; in most cases, the broad enantiotropic SmC phase formed by the parent isomers is suppressed by the addition of the phenoxy end-group. However, detailed analyses by small-angle X-ray scattering and monodomain 2D X-ray scattering suggest that these compounds form a SmA phase with a partially intercalated bilayer structure in which the phenoxy end-groups are nanosegregated. Such an intercalated bilayer structure might enable the tuning of smectogenic properties by appropriate substitution of the phenoxy end-groups.     

Enhanced chemical reworkability of DGEBA thermosets cured with rare earth triflates using aromatic hyperbranched polyesters (HBP) and multiarm star HBP‐b‐poly(ε‐caprolactone) as modifiers

A hyperbranched aromatic polyester (HBPOH) has been synthesized, and poly(ε‐caprolactone) arms have been grown on some of its end hydroxyl groups (HBPCL). These modifiers have been used in cationic diglycidyl ether of bisphenol A formulations cured with ytterbium triflate as cationic initiator. The effect of HBPOH and HBPCL on the curing kinetics has been studied using differential scanning calorimetry (DSC). The obtained materials have been characterized by dynamomechanical analysis, DSC, thermogravimetric analysis and mechanical tests. The modifiers are incorporated into the thermosetting network because of the participation of the end hydroxyl groups in the cationic curing of epoxides by the activated monomer mechanism. Homogeneous thermosets have been obtained with a remarkable increase in impact strength without sacrificing elastic modulus or hardness. A compromise between the rigid structure of the aromatic hyperbranched core and the flexibilizing effect of the poly(ε‐caprolactone) arms is believed to be responsible for the overall thermal and mechanical properties of the materials. The use of these polymeric modifiers increases the thermal stability of the resulting materials because of the low degradability of the aromatic ester groups in the hyperbranched core and the incorporation of the modifier into the network structure. However, the presence of such ester groups makes them reworkable by hydrolysis or alcoholysis in an alkaline medium, thus opening a way for recovery of valuable substrates. Copyright © 2013 John Wiley & Sons, Ltd.     

Simulation of mesogenic diruthenium tetracarboxylates: Development of a force field for coordination polymers of the MMX type

A classical molecular mechanics force field, able to simulate coordination polymers (CP) based on ruthenium carboxylates (Ru₂(O₂CR_eq)₄L_ax) (eq = equatorial group containing aliphatic chains, L_ax= axial ligand), has been developed. New parameters extracted from experimental data and quantum calculations on short aliphatic chains model systems were included in the generalized AMBER force field. The proposed parametrization was evaluated using model systems with known structure, containing either short or long aliphatic chains; experimental results were reproduced satisfactorily. This modified force field, although in a preliminary stage, could then be applied to long chain liquid crystalline compounds. The resulting atomistic simulations allowed assessing the relative influence of the factors determining the CP conformation, determinant for the physical properties of these materials. © 2013 Wiley Periodicals, Inc.