PVT,viscosity, and surface tension of ethanol: New measurements and literature data evaluation

In this work, the results of density, viscosity, and surface tension measurements for ethanol are presented. Ethanol with stated mass fraction purity greater than 0.998 was further purified using molecular sieves. Density was measured within the temperature and pressure ranges, respectively, T = (278.15 to 353.15) K and p = (0.1 to 35) MPa by means of a vibrating tube densimeter, model DMA 512P from Anton Paar with an estimated uncertainty of ±0.5 kg · m^?3. The experimental (p, ρ, T) results have been correlated by Tait equation. From this equation the isobaric expansivity, the isothermal compressibility, and the thermal pressure coefficient have been calculated. Viscosity was measured over the range T = (273.15 to 346.15) K using an Ubbelohde viscometer with a Schott–Geräte automatic measuring unit (Model AVS-470) with the associated uncertainty of ±0.001 mPa · s. The measured values were combined with selected values from the literature covering the range T = (223 K to 503) K, and the VTF model has been fitted to all the data. The surface tension of the liquid was measured using a tensiometer KSV Sigma 70 with a Du-Noüy ring for the range of T = (274.77 to 318.99) K with an uncertainty of ±0.01 mN · m^?1. Using these data and critically assessed data of other authors compiled from the literature, a form of the IAPWS equation was used to correlate the surface tension within the temperature range 223 K up to the critical temperature.     

Non-extensive statistical entropy,quantum groups and quantum entanglement

In this work, we explore a new connection between quantum groups and Tsallis entropy through the energy spectrum of a Hamiltonian with S_Uq(2)$S{U}_q\left(2\right)$ symmetry. Identifying the deformation parameter of the entropy with the parameter of deformation of the associated quantum group, we deduce Tsallis entropy for states related to such a system with S_Uq(2)$S{U}_q\left(2\right)$ symmetry and conducted an investigation of quantum entanglement.     

Liquid–liquid equilibrium of (1H,1H,7H-perfluoroheptan-1-ol + perfluoroalkane) binary mixtures

This work presents new liquid–liquid equilibrium data for mixtures of 1H,1H,7H-perfluoroheptan-1-ol and linear perfluoroalkanes from C₆ to C₉. Data were measured at atmospheric pressure by turbidimetry and at pressures up to 5 MPa using a laser light scattering technique. The coexistence curves have been fitted to renormalization group extended-scaling expressions with the critical temperature and molar fraction obtained from the fit.     

Colorimetric methodology for monitoring the cellulose insulating paper degradation in electrical equipments filled with mineral oil

During the operation of electrical equipments the compound 2-furfuraldehyde (2-FAL) and other related furanic substances are produced from the insulating paper degradation and can be detected in the mineral oil by high performance liquid chromatography (HPLC). Their concentration increase can be used to estimate the quality of the paper insulation inside the equipments. In this work colorimetric methodologies for quantification of these furanic degradation products in oil filled electrical equipment were evaluated. Two analytical methods were studied using aniline and modified Winkler’s reactions. For this purpose used oil samples and 2-FAL standard oil solutions were analyzed and the results for both methods were compared with HPLC analysis. The obtained results for 2-FAL standard oil solutions were in accordance with both methodologies. The results obtained for used mineral oil showed that the analysis of furanic compounds by the colorimetric methods may induce to false positive results due to the interference of oil oxidation by-products in the quantitative analysis.     

Tetra‐μ‐acetato‐bis{[1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene]rhodium(II)}(Rh—Rh) tetrahydrofuran tetrasolvate

In this paper, we compare and discuss the very different crystal structures and supramolecular arrangements obtained when using different crystallization solvents with the same organometallic moiety. The new title tetrahydrofuran (THF) solvate, [Rh₂(C₂H₃O₂)₄(C₂₇H₃₆N₂)₂]·4C₄H₈O, is compared with the toluene trisolvate reported previously by us [Góis, Trindade, Veiros, Andre, Duarte, Afonso, Caddick & Cloke (2007). Angew. Chem. Int. Ed. 46 , 5750–5753]. The molecular structures of the two complex molecules display a similar conformation, but due to the presence of different solvent molecules, the two solvates crystallize in different space groups and exhibit quite diverse supramolecular assemblies. The toluene solvate crystallizes in the triclinic space group P, while in the presence of THF, the monoclinic P2₁/c space group is obtained, with the complex molecule residing on an inversion centre. The resulting crystal packing displays no classical hydrogen bonds but different supramolecular synthons give rise to different packing motifs. In this work, we highlight the different supramolecular architectures obtained when organometallic moieties crystallize with different solvent molecules. We compare the novel structure of the THF derivative with that of the toluene solvate of a dirhodium(II) complex belonging to a new family of catalyst compounds exhibiting very high performance in arylation processes.     

SERS studies of DNA nucleobases using new silver poly(methyl methacrylate) nanocomposites as analytical platforms

The implementation of polymer‐based composites provides a plausible alternative to develop efficient, handy and scalable substrates for surface‐enhanced Raman spectroscopy (SERS) aiming the widespread use of this technique for chemical analysis and molecular sensing. In this research, new poly(methylmethacrylate) based nanocomposites for SERS were prepared by in situ miniemulsion polymerization in the presence of organically capped metal silver nanoparticles. The ensuing composites have been investigated as analytical platforms for SERS detection of DNA constituents for variable analytical conditions. Finally, we show that in special cases, selective detection of DNA bases by SERS can be possible by varying the pH of the solution under analysis. Copyright © 2014 John Wiley & Sons, Ltd.     

Heterodimetallic germanium(IV) complex structures with transition metals

The hydrothermal synthesis and structural characterization of a number of complex compounds containing the divalent tris(oxalato-O,O')germanate anion, [Ge(C2O4)3]2-, or the neutral bis(oxalate-O,O')germanium fragment, [Ge(C2O4)2], with transition-metal (M) cationic complexes of 1,10'-phenanthroline (phen) is reported: [M(phen)3][Ge(C2O4)3].xH2O [where M2+ = Cu2+ (1a and 1b), Fe2+ (2a and 2b), Ni2+ (3), Co2+ (4); x = 0.2 for 2b], [MGe(phen)2(mu2-OH)2(C2O4)2] [where M2+ = Cd2+ (5) and Cu2+ (6)]. The isolation of two polymorphs with Cu2+ (1a and 1b) and other pseudo-polymorphs for Fe2+ (2a and 2b) was rationalized based on slightly different molar ratios for the starting materials. All compounds have been characterized using EDS, SEM, vibrational spectroscopy (FT-IR and FT-Raman), thermogravimetry, and CHN elemental composition and their structure determined on the basis of single-crystal X-ray diffraction studies. The crystal packing of the different chemical moieties for each series of compounds was discussed on the basis of the various intermolecular interactions present (strong C-H...pi and weak C-H...O hydrogen-bonding interactions, C-H...pi and pi-pi contacts).     

Multiple Emulsion Templating of Hybrid Ag/SiO2 Capsules for Antibacterial Applications

Silver nanoparticles (NPs) encapsulated in amorphous silica shells are synthesized and evaluated for their antibacterial action using the Gram‐negative Escherichia coli bacterium. These inorganic capsules are synthesized using a new approach that comprises the use of oil‐in‐water‐in‐oil (O/W/O) multiple emulsions to fabricate SiO₂ capsules incorporating organically capped Ag NPs. This strategy is explored as a mean to promote the bioadhesion of the microorganisms to the silica rough surfaces while still keeping the system with a high surface area for the active metal. The results have shown that the hybrid capsules enable a slow release of cationic silver from the interior of the silica microsphere to the external medium probably through the pore channels in the shell. The antibacterial activity against E. coli is mainly determined by the Ag⁺ ion release rate, suggesting that these particulates can be employed as a robust system for prolonged used as an antimicrobial material.     

Monitoring the process mean based on attribute inspection when a small sample is available

This paper proposes a new control chart, denoted by Open image in new window to evaluate the stability of a process mean when a small sample is available. This chart is based on attribute inspection rather than the physical measurements (taken with an instrument, such as a caliper or precision balance) of the quality characteristics of interest of the sampled items. The main goal is to recover measurements on a continuous scale by generating random measurements using the frequencies observed for the sample as inputs. The average sample obtained using these recovery measures ( Open image in new window ) is calculated and used to draw the standard Open image in new window chart. The average sample Open image in new window can be shown to be a mixture of normal distributions. The values of the lower control limit (LCL) and the upper control limit (UCL) are chosen to minimize the average run length (ARL).