Separation and Determination of Nitroguanidine and Guanidine Nitrate by HPTLC

High-performance thin-layer chromatography has been used for separation and quantification of nitroguanidine and guanidine nitrate, for online and off-line quality control of synthesis. The compounds were separated on silica gel 60 F₂₅₄ layers with dioxane–tetrahydrofuran 1:1 (v/v), as mobile phase. UV detection was performed at 210 and 265 nm for guanidine nitrate and nitroguanidine, respectively. Quantitative analysis was performed by absorbance densitometry and use of peak area. Validation was performed taking into consideration the special features of the method.     

An approach to the synthesis and characterization of HMS/Pr-Rh-Zr as efficient catalyst for synthesis of tetrahydrobenzo[b]pyran and 1,4-dihydropyrano[2,3-c]pyrazole derivatives

Research on Chemical Intermediates - The aim of present investigation is the synthesis of mesoporous catalyst based on hexagonal mesoporous silica. HMS support has exceptional properties such as...     

Chemical effects induced by γ-irradiated alkali halides in aqueous binary mixtures of nitrates and iodides

Dissolution of -irradiated chlorides of sodium and potassium in a solution of NaNO₃ and KI results in the formation of NO ₂ ^– and iodine as stable products. The variation in the yields of the products with the amount of irradiated salts is studied. The effect of photoannealing of the irradiated salts on the yields of nitrate and iodine in the mixture is discussed on the basis of photoannealing reactions of the colour centres.     

4E analysis and three-objective optimization for selection of the best prime mover in smart energy systems for residential applications: a comparison of four different scenarios

Journal of Thermal Analysis and Calorimetry - Recently, using integrated energy systems for residential-scale applications has been of great interest to the researchers. The objective of this study...     

Determination of RDX and Keto-RDX in High-Explosive Mixtures by High-Performance Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - High-performance thin-layer chromatography (HPTLC) has been used for separation and quantitation of components of high explosives...     

Change in ~7Be half-life in host media

First-principle calculations within the density functional theory framework are used to study the probability of electron capture for the ~7Be nucleus.For this purpose,electron density at the ~7Be nucleus is computed in Al,Au,Pd,Pt,and Pb environments.Our results show that the half-life of ~7Be is changed by implanting ~7Be in host environments.Electron affinity of the media and confinement effects are responsible for the change in the half-life of ~7Be nucleus.Moreover,electric potential at the ~7Be nucleus is calculated.Results show that variations in electric potential are usually consistent with those in electron density at the ~7Be nucleus.     

Intermolecular interaction of a neutral polymeric bonding agent containing N-Vinylpyrrolidone units with ammonium perchlorate and Keto-RDX

The interaction of a new neutral polymeric bonding agent (NPBA) containing N-Vinylpyrrolidone units with two types of oxidizers (ammonium perchlorate and Keto-RDX) was investigated by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). NPBA forms a layer of film on the surface of oxidizers. The paper gives hypothetical mechanisms for improving significantly mechanical properties by addition of the neutral polymeric bonding agent (NPBA).     

Magnetic and Thermal Properties of Novel Poly(ether-amide)/Fe3O4 Nanocomposite Containing Phosphine Oxide Group

New poly(ether-amide) nanocomposite containing phosphine oxide was prepared via solution polymerization process from synthesized poly(ether-amide) and Fe₃O₄ nanoparticles in a solution of N,N-dimethylformamide. Uniform monodisperse Fe₃O₄ nanoparticles were synthesized at room temperature via a facile sonochemical reaction. Poly(ether-amide) (PEA) as the polymer matrix was synthesized from reaction of 1,4-(4-carboxy phenoxy)butane (1) and bis(3-amino phenyl)phenyl phosphine oxide (2) via a direct polycondensation reaction. Nanoparticle and nanocomposite were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared. The effect of the presence of Fe₃O₄ nanoparticles on the thermal properties of PEA was studied using thermogravimetric analysis in nitrogen atmospheres. The magnetic properties of the sample were also investigated using an alternating gradient force magnetometer. We found that the Fe₃O₄ nanoparticles exhibit a ferromagnetic behaviour with a saturation magnetization of 59 emu/g and a coercivity of 104 Oe at room temperature. The coercivity of PEA/Fe₃O₄ nanocomposites is found to be 126 Oe, higher than 104 Oe which is obtained for Fe₃O₄.     

The Effect of Flower-Like Magnesium Hydroxide Nanostructure on the Thermal Stability of Cellulose Acetate and Acrylonitrile–Butadiene–Styrene

Flower-like magnesium hydroxide (Mg(OH)₂) nanostructures were synthesized via a simple hydrothermal reaction at relatively low temperature. The Mg(OH)₂ nanostructures were then added to acrylonitrile–butadiene–styrene (ABS) and cellulose acetate (CA) polymers. The effect of Mg(OH)₂ nanostructures on the thermal stability of the polymeric matrixes has been investigated. The thermal decomposition of the nanocomposites shifts towards higher temperature in the presence of the Mg(OH)₂. The enhancement of thermal stability of nanocomposites is due to endothermically decomposition of magnesium hydroxide that releases of water and dilutes combustible gases. Nanostructures and nanocomposites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), differential thermal analysis (DTA), UL-94 test and limiting oxygen index (LOI) analysis.     

On Finite n-Acentralizer Groups

Let G be a group and Aut(G) be the group of automorphisms of G. Then the Acentralizer of an automorphism α ∈Aut(G) in G is defined as C _G (α) = {g ∈ G∣α(g) = g}. For a finite group G, let Acent(G) = {C _G (α)∣α ∈Aut(G)}. Then for any natural number n, we say that G is n-Acentralizer group if |Acent(G)| =n. We show that for any natural number n, there exists a finite n-Acentralizer group and determine the structure of finite n-Acentralizer groups for n ≤ 5.