Highly selective R,S-coordination of non racemic (1R,2R)-(1,2-dialkyl)-1,2-diamine cyclohexane derivatives to palladium dichloride

In non-racemic (1R,2R)-(1,2-dialkyl)-1,2-diaminocyclohexane palladium dichloride complexes the C2 symmetry of the diamine ligand is broken, resulting in selective R,S-coordination.     

Molecular dynamics simulation in the grand canonical ensemble

An extended system Hamiltonian is proposed to perform molecular dynamics (MD) simulation in the grand canonical ensemble. The Hamiltonian is similar to the one proposed by Lynch and Pettitt (Lynch and Pettitt, J Chem Phys 1997, 107, 8594), which consists of the kinetic and potential energies for real and fractional particles as well as the kinetic and potential energy terms for material and heat reservoirs interacting with the system. We perform a nonlinear scaling of the potential energy parameters of the fractional particle, as well as its mass to vary the number of particles dynamically. On the basis of the equations of motion derived from this Hamiltonian, an algorithm has been proposed for MD simulation at constant chemical potential. The algorithm has been tested for the ideal gas, for the Lennard-Jones fluid over a wide range of temperatures and densities, and for water. The results for the low-density Lennard-Jones fluid are compared with the predictions from a truncated virial equation of state. In the case of the dense Lennard-Jones fluid and water our predicted results are compared with the results reported using other available methods for the calculation of the chemical potential. The method is also applied to the case of vapor-liquid coexistence point predictions.     

A complete classification of 3‐(11, 4, 4) designs with nontrivial automorphism group

In this paper, we classify all simple 3‐(11, 4, 4) designs with nontrivial automorphism group. A computational method based on the standard basis of trades is developed and a total of 51,267,240 nonisomorphic designs is produced. © 2000 John Wiley & Sons, Inc. J Combin Designs 8: 419–425, 2000     

Rational solutions and lump solutions to a non-isospectral and generalized variable-coefficient Kadomtsev–Petviashvili equation

Nonlinear Dynamics - In this work, a non-isospectral and variable-coefficient Kadomtsev–Petviashvili equation is considered using Hirota’s bilinear form and a direct assumption with...     

Seed Priming with Non-thermal Plasma Modified Plant Reactions to Selenium or Zinc Oxide Nanoparticles: Cold Plasma as a Novel Emerging Tool for Plant Science

Plasma Chemistry and Plasma Processing - This research explored the capability of seed priming with the non-thermal plasma to modify reactions of Melissa officinalis, an important medicinal plant,...     

Polypyrrole coatings on rheocast aluminum-silicon alloy: A correlation between properties and electrodeposition conditions

The effect of the electrolyte composition and the deposition potential range on the physical properties and possible corrosion protection effect of polypyrrole coatings on rheocast aluminum–2.5 % silicon alloy is investigated. Solutions with different concentrations of sodium nitrate and an electron transfer mediator reagent were used for the electrodeposition. Polypyrrole coating is able to hinder the entrance of electrolyte. Upon the penetration of chloride ions, the coating can induce passivation of the alloy's surface by its reduction. The thickness of the coating and its ion-barrier properties, controlled by the electrodeposition conditions, are shown as the important factors influencing the protection efficiency. However, localized drastic galvanic coupling at the polypyrrole/aluminum interface forms blisters, causes failure, and limits the possible protection.     

Thermoanalytical investigation of relative reactivity of some nitrate oxidants in tin-fueled pyrotechnic systems

In order to investigate relative reactivity of different oxidants in solid-state reactions of pyrotechnic mixtures, thermal properties of Sn + Sr(NO₃)₂, Sn + Ba(NO₃)₂, and Sn + KNO₃ pyrotechnic systems have been studied by means of TG, DTA, and DSC methods and the results compared with those of pure oxidants. The apparent activation energy (E), ΔG ^#, ΔH ^#, and ΔS ^# of the combustion processes were obtained from the DSC experiments. The results showed that the nature of oxidant has a significant effect on ignition temperature, and the kinetic of the pyrotechnic mixtures’ reactions, and the relative reactivity of these mixtures was found to obey in the following order: Sn + Sr(NO₃)₂ > Sn + Ba(NO₃)₂ > Sn + KNO₃.     

Reducing Photoyellowing of Wool Using Nano TiO2

Wool is the most important animal fiber used in textile industries, but its photostability is very low. Scientists have searched for new ways to increase the photostability of wool. As TiO₂ nano particles have features suitable for new applications, the UV-blocking power of nano TiO₂ may be used for protecting fabrics against UV rays. Treatment of wool with TiO₂ can be effective for controlling photodegradation. This study focused on protecting wool fabric against UV rays using nano TiO₂. To this end, oxidized and raw wool were treated with citric acid as the cross-linking agent and different concentrations of nano TiO₂. The whiteness and yellowness of wool fabric samples were reported. XRD patterns proved the existence of TiO₂ nano-particles on the wool surface. Finally, the results revealed that nano TiO₂ is a suitable UV absorber on wool fabric and its effect depends on concentration.     

Preparation of nonspherical particles via dual-seeded dispersion polymerization in the presence of saturated hydrocarbon droplets

In this study, the effect of various polymerization conditions on the shape of the particles produced by dual-seeded dispersion polymerization of a second monomer with polystyrene (PS) and poly(methyl methacrylate) (PMMA) seed particles in the presence of saturated hydrocarbon droplets in a polar media was discussed. It was observed that with changing the affinity between the hydrocarbon and PS seed particles, second monomer type, polarity, and alcohol type of the medium nonspherical particles with a variety of shapes can be produced. Furthermore, we suggested that the presence of PMMA seed particles in the medium affects the distribution of the second polymer domains on the surface of the PS seed particles in addition to the absorbed amount of the hydrocarbon by PS particles and second polymer domains and the distribution of the hydrocarbon between them. Moreover, the experimental results showed that almond shell-like PS particles can be prepared under certain conditions.