Implications of minimal length scale on the statistical mechanics of ideal gas

Several alternative approaches to quantum gravity problem suggest the modification of the fundamental volume ω₀ of the accessible phase space for representative points. This modified fundamental volume has a novel momentum dependence. In this paper, we study the effects of this modification on the thermodynamics of an ideal gas within the micro-canonical ensemble and using the generalized uncertainty principle (GUP). Although the induced modifications are important only in quantum gravity era, possible experimental manifestation of these effects may provides strong support for underlying quantum gravity proposal.     

Microwave-assisted simple, one-pot, four-component synthesis of 2,4,6-triarylpyrimidines under solvent-free conditions

2,4,6-Triarylpyrimidines are synthesized via a simple, one-pot, four-component reaction between aryl methyl ketones, benzaldehydes, aromatic nitriles, and hydroxylamine under microwave irradiation and solvent-free conditions in good to excellent yields.     

Model reaction related to cytochrome P-450: effect of substitution on the rate of naphthalene oxidation

A kinetic method for measuring the relative rates of hydroxylation of naphthalene derivatives/cyclohexene has been developed. With this technique a linear relationship between the logarithm of the rates of oxidation products and the oxidation potentials of the naphthalene derivatives has been observed. Plots of σ Hammett and σ⁺ Hammett–Brown with logarithm of relative rates have been linear and shown ρ = −0.98 and ρ⁺ = −0.58, respectively. This contrast aromatic oxidation in protic solvents in which the oxidation products are naphthoquinones and provides further evidence for the intermediacy of carbocation in the hemin catalyzed hydroxylation of aromatic rings.     

Viscous Interaction Between a Vortex Tube and a Rotating Spherical Particle

The transient advection of a cylindrical vortex tube in a viscous incompressible flow field and its interaction with a rotating/spinning spherical particle has been investigated numerically at Reynolds numbers in the range of 20≤ Re≤200 for angular velocities of 0≤Ω≤0.5. The effects of vortex parameters such as size, circulation strength and initial position relative to the particle, on the temporal behavior of the lift and drag forces are studied. Vortex‐sphere interactions bring about major changes in the flow field particularly when coupled with particle rotation. It is observed that the forces acting on the particle are significantly influenced during the time that the vortex core is in the vicinity of the particle. The extent of these local changes are about ±30% in the drag coefficient and about ±200% in the lift coefficient as compared to flow over a rotating solid sphere with no vortex interaction. It is also found that a vortex with core radius between one and two particle diameters creates the strongest temporal variations in the lift and drag coefficients. Furthermore, maximum lift variations occur for the vortex‐particle head on collision, while a vortex with an offset distance of about one diameter from the principal flow axis generates the maximum drag variations.     

Adsorptive Removal of Thorium(IV) from Aqueous Solutions Using Synthesized Polyamidoxime Chelating Resin: Equilibrium,Kinetic, and Thermodynamic Studies

In this study, an amidoximated chelating ion exchange resin was prepared by poly-acrylonitrile (PAN) grafted potato starch. The adsorbent characterizations such as specific surface area, pore volume, average pore radius, and Fourier transform infrared (FTIR) spectrum of the resin were measured. The effects of pH, adsorbent dosage, contact time, initial concentration of thorium ion, and temperature on adsorption of thorium ion from aqueous solutions were investigated. Four isotherm models including Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin were applied to analyze the equilibrium isotherm data. The results showed that Langmuir and Temkin models had a good agreement with experimental data. The maximum capacity of the adsorbent using the Langmuir isotherm model was 227.27 mg · g^?1. The kinetic models like pseudo-first-order, pseudo-second-order, Elovich, and intraparticle were examined to describe the adsorption process. The kinetics of the adsorption process was found to follow the pseudo-second-order kinetic model. The thermodynamic parameters (ΔG°, ΔH°, ΔS°) were also calculated using equilibrium constant values at various temperatures (25, 35, 45, 55°C) and the positive value for ΔH° showed an endothermic adsorption process. The study suggests that the prepared adsorbent has promising potential for the removal of thorium from wastewaters.      

Ultrasound irradiation and green synthesized CuO-NiO-ZnO mixed metal oxide: An efficient sono/nano-catalytic system toward a regioselective synthesis of 1-aryl-5-amino-1H-tetrazoles

Abstract

An efficient approach has been reported that 1-aryl-5-amino-1H-tetrazoles are prepared from structurally diverse N-arylcyanamides and sodium azide using sono/nano-catalytic system. The mixed metal oxide nanoparticles (NPs) (CuO, NiO, and ZnO NPs) were prepared with utilizing aqueous leaves extracts of the Rheum ribes. In this study, the effect of the reaction condition was investigated on the catalytic activity and selectivity of mixed metal oxide NPs for the synthesis of aminotetrazole derivatives. In this regard, various reaction conditions were precisely compared such as reflux and ultrasonication (US). In this study, the regioselective synthesis of 1-aryl-5-amino-1H-tetrazoles with high yield was achieved by the synergistic effect between US irradiation and prepared nanocatalyst which showed the potential of sono/nano-catalytic system in organic synthesis. Furthermore, the as-prepared nanocatalyst could be reused and recovered from the reaction mixture for several times without consequential abate in its catalytic activity and selectivity.     

4-Methyl morpholinium bis-(thio)barbiturates: Synthesis,structure, anticancer evaluation,and CoMFA study

The reaction of symmetrical (thio)barbituric acids with aldehydes in the presence of 4-methyl morpholine yielded a new form of 4-methyl morpholinium bis-(thio)barbiturate containing charge-separated intermolecular and eight-membered intramolecular H-bonds. X-ray Crystallography, FT-IR, and ¹H and ¹³C-NMR spectroscopy techniques were used for structure characterizations. Some of these compounds showed potent anticancer activities. Cytotoxicity of the synthetic compounds against HeLa and MCF-7 cell lines were performed by MTT assay. In addition, a comparative molecular field analysis was carried out, and the effects of substituents on the biological activities of these compounds were explained.     

Synthesis and fluorescent properties of some Furan-tagged Thieno[2,3-d]pyrimidines and Thieno[2,3-d:4,5-d']dipyrimidines

Intermolecular cyclization of pyrimidinethiol 1 with ethyl chloroacetate and chloroacetonitrile furnished thieno[2,3-d]pyrimidines 2a,b . Hydrazinolysis of o-aminoester 2a gave acid hydrazide 3, which was cyclized with various electrophilic reagents including formic acid, triethyl orthoformate, acetic anhydride, p-chlorobenzaldehyde then triethyl orthoformate, carbon disulfide, and acetylacetone affording thienopyrimidine derivatives 4 to 10 . Another thienopyrimidine series could be obtained via treatment of o-aminocarbonitrile 2b with a variety of reagents giving derivatives 11 to 17 . The fluorescent measurements for a group of the synthesized compounds at room temperature demonstrated high fluorescent properties.     

Reaction of Isonitriles with Dibenzoylacetylene Leading to Furan and Difuropyran Derivatives

A mixture of an isocyanide and dibenzoylacetylene in dry CH₂Cl₂ undergoes a smooth addition reaction at ambient temperature to furnish 3‐[5‐(alkylimino)‐3,4‐dibenzoyl‐2‐phenylfuran‐2(2H)‐yl]‐ 1‐phenylprop‐2‐yn‐1‐ones (1 : 2 adduct) and {2,5‐bis(alkylimino)‐4,7,8a‐triphenyl‐5H‐difuro[2,3‐b:3′,4′‐e]pyran‐3(8aH)‐yl}(phenyl)methanones (2 : 2 adduct). Single‐crystal X‐ray analyses conclusively confirmed the structures of the adducts.     

Magnetic ion imprinted polymer nanoparticles for the preconcentration of vanadium(IV) ions

An ion imprinted polymer coated onto magnetite (Fe₃O₄) nanoparticles is shown to be a useful magnetic sorbent for the fairly selective preconcentration of vanadium. The sorbent was prepared by radical copolymerization of 3-(triethoxysilyl)propyl methacrylate (the monomer), ethylene glycol dimethacrylate (the cross-linker), and the vanadium(IV) complex of 1-(2-pyridylazo-2-naphthol) in the presence of magnetite nanoparticles. The material was characterized by IR spectroscopy, scanning electron microscopy, and thermal analysis. The vanadium(IV) ions were removed from the imprint by a solution containing thiourea and HCl, and the eluent was submitted to AAS. The analytical efficiency and relative standard deviation are 99.4 and ±2.3 %, respectively, under optimum conditions, and the limit of detection is 20 ng mL^?1. The method was successfully applied to the preconcentration and determination of vanadium(IV) ions in crude oil. Figure

An ion imprinted polymer is coated on to magnetite nanoparticles as a useful magnetic sorbent for the fairly selective preconcentration of vanadium which can be used for vanadium determination in crude oil.