Investigation of antioxidant and electron beam radiation effects on the thermal oxidation stability of low-density polyethylene

Effect of various antioxidants on the thermal oxidation stability of LDPE and X-LDPE has been investigated. To achieve this purpose, miscellaneous commercial grade antioxidants such as Irganox 1010, Irganox1076, Irgafos168, Irganox B225, and Chimassorb 944 were selected. Then, formulations based on different content of antioxidant were prepared. The samples were crosslinked by exposure to electron beam irradiation. To assess the thermal oxidation stability of samples, oxidation induction time (OIT) test was accomplished on both the irradiated and unirradiated specimens. Ageing tests were carried out in order to evaluate the thermal oxidation stability of irradiated X-LDPE. The results indicate that Irganox 1010 is the most effective antioxidant amongst the selected ones, concerning thermal oxidation stability of LDPE, before and after aging test.     

Hydrodynamic analysis of a heat exchanger with crosscut twisted tapes and filled with thermal oil-based SWCNT nanofluid: applying ANN for prediction of objective parameters

Journal of Thermal Analysis and Calorimetry - Present study investigates hydrodynamic analysis of heat exchanger with crosscut twisted tapes and filled with thermal oil-based SWCNT nanofluid (NF)....     

Energy and mass transport of Casson nanofluid flow over a slanted permeable inclined surface

In this problem, examination of Casson nanofluid flow over nonlinear slanted extending sheet with chemical reaction and heat generation/absorption influences are under thought. Nanofluid exhibits in this examination is established on Buongiorno model. The governing nonlinear PDE’s are reduced to nonlinear ODE’s by employing suitable transformations. The Keller-box numerical technique is considered for simulation of this research. The influence of chemical reaction and nonlinear parameter on concentration and velocity distribution is analyzed. The recovered results exhibit that the impact of inclination and Casson factor reduced liquid velocity. While energy and mass transport rates are increased against inclination factor. Numerical and graphical outcomes are additionally exhibited in tables and graphs.

     

Synthesis of 2‐aryl‐1‐arylmethyl‐1H‐1,3‐benzimidazoles catalysed by ferric ammonium sulfate (NH4Fe(SO4)2) under solvent‐free conditions

NH₄Fe(SO₄)₂ was found to be a mild and effective catalyst for the selective synthesis of 2‐aryl‐1‐arylmethyl‐1H‐1,3‐benzimidazoles under solvent‐free conditions. Copyright © 2015 John Wiley & Sons, Ltd.     

Visual DNA as a diagnostic tool

We report on the incorporation of the Visual DNA concept in a genotyping assay as a simple and straightforward detection tool. The principle of trapping streptavidin‐coated superparamagnetic beads of micrometer size for visualization of genetic variances is used for PrASE‐based detection of a panel of mutations in the severe and common genetic disorder of cystic fibrosis. The method allows a final investigation of genotypes by the naked eye and the output is easily documented using a regular hand‐held device with an integrated digital camera. A number of samples were run through the assay, showing rapid and accurate detection using superparamagnetic beads and an off‐the‐shelf neodymium magnet. The assay emphasizes the power of Visual DNA and demonstrates the potential value of the method in future point‐of‐care tests.     

Syntheses and spectroscopic investigation of some cyclophosphazanes: Analysis of pseudo‐triplet splitting

Some new phosphoramidates, 1–3 , and the corresponding cyclophosphazanes, 4–6 , with formula Cl₂P(p‐NHC₆H₄CH₃) 1 , Cl₂P(O)(p‐NHC₆H₄NO₂) 2 , (CH₃)₂NP(O)Cl(p‐NHC₆H₄CH₃) 3 , [ClP(p‐NC₆H₄CH₃)]₂ 4 , [ClP(O)(p‐NC₆H₄NO₂)]₂ 5 , and [(CH₃)₂NP(O)(p‐NC₆H₄CH₃)]₂ 6 were synthesized and characterized by ¹H, ¹³C, ³¹P NMR, IR, mass spectroscopy, and elemental analysis. A pseudo‐triplet signal was observed in the ¹H NMR spectrum of molecule 6 for the N(CH₃)₂ protons. The A₆A′ ₆X₂ spin system was suggested for the pseudo‐triplet pattern of ³J_PNCH coupling in this molecule. Ab initio calculations were performed at the HF and B3LYP levels of theory with 6‐311G^** standard basis set on the geometry of compound 6 . Also, the NMR chemical shift calculations were done to compare the computed results with the experimental ones. The calculated results are in good agreement with experimental data. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:337–343, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20229     

Synthesis of bis(1,5-disubstituted tetrazoles) via double four component Azido-Ugi reaction

A double four component Azido-Ugi reaction of isocyanide, TMSN₃, aldehyde, and 4,4′-sulfonyldianiline with two amine functional groups in MeOH at 65°C has been described. The synthesis of pharmacologically and structurally interesting compounds with two 1,5-disubstituted tetrazole rings via a reaction from available and inexpensive reagents under a convenient process and mild reaction conditions has been reported. Modifications in the structure of the reaction product could be followed by varying the aldehyde or isocyanide component. The products are new and were well described by Mass, ¹H NMR, and ¹³C NMR spectral studies.     

Modeling the Stretch Behavior of the Single-Crystal Ni–Al Alloy and Its Molecular Dynamics Simulation

Physics of the Solid State - Molecular dynamics simulation was employed in this study to investigate the atomistic mechanisms involved in the Ni–Al alloy homogeneous deformation and the...     

New Model for Polymerization of Oligomeric Alcohol Dehydrogenases into Nanoaggregates

Polymerization and self-assembly of proteins into nanoaggregates of different sizes and morphologies (nanoensembles or nanofilaments) is a phenomenon that involved problems in various neurodegenerative diseases (medicine) and enzyme instability/inactivity (biotechnology). Thermal polymerization of horse liver alcohol dehydrogenase (dimeric) and yeast alcohol dehydrogenase (tetrameric), as biotechnological ADH representative enzymes, was evaluated for the development of a rational strategy to control aggregation. Constructed ADH nuclei, which grew to larger amorphous nanoaggregates, were prevented via high repulsion strain of the net charge values. Good correlation between the variation in scattering and λ ⁻² was related to the amorphousness of the nanoaggregated ADHs, shown by electron microscopic images. Scattering corrections revealed that ADH polymerization was related to the quaternary structural changes, including delocalization of subunits without unfolding, i.e. lacking the 3D conformational and/or secondary-ordered structural changes. The results demonstrated that electrostatic repulsion was not only responsible for disaggregation but also caused a delay in the onset of aggregation temperature, decreasing maximum values of aggregation and amounts of precipitation. Together, our results demonstrate and propose a new model of self-assembly for ADH enzymes based on the construction of nuclei, which grow to formless nanoaggregates with minimal changes in the tertiary and secondary conformations.