FT-IR Investigation of the Structural Changes of Sulcis and South Africa Coals under Progressive Heating in Vacuum: Correlation with Volatile Matter

The analysis of gas evolving during the pyrolysis of two very different rank coals was studied by using FT-IR spectroscopy. These coals, coming from Sulcis (Sardinia, Italy) and from South Africa, respectively, were subjected to progressive heating up to 800°C in vacuum. The thermal destruction of coal was followed by monitoring the production of gases in this range of temperature. The gases evolving in the heating from room temperature to 800°C were collected at intervals of 100°C and analysed by infrared spectroscopy. The relative pressures were plotted against temperature. These graphs clearly show the correlation among qualitative gas composition, temperature, and the maximum value of emissions, thus confirming FT-IR analysis as a powerful key for pyrolysis monitoring

How future surgery will benefit from SARS-COV-2-related measures: a SPIGC survey conveying the perspective of Italian surgeons

COVID-19 negatively affected surgical activity, but the potential benefits resulting from adopted measures remain unclear. The aim of this study was to evaluate the change in surgical activity and potential benefit from COVID-19 measures in perspective of Italian surgeons on behalf of SPIGC. A nationwide online survey on surgical practice before, during, and after COVID-19 pandemic was conducted in March-April 2022 (NCT:05323851). Effects of COVID-19 hospital-related measures on surgical patients' management and personal professional development across surgical specialties were explored. Data on demographics, pre-operative/peri-operative/post-operative management, and professional development were collected. Outcomes were matched with the corresponding volume. Four hundred and seventy-three respondents were included in final analysis across 14 surgical specialties. Since SARS-CoV-2 pandemic, application of telematic consultations (4.1% vs. 21.6%; p < 0.0001) and diagnostic evaluations (16.4% vs. 42.2%; p < 0.0001) increased. Elective surgical activities significantly reduced and surgeons opted more frequently for conservative management with a possible indication for elective (26.3% vs. 35.7%; p < 0.0001) or urgent (20.4% vs. 38.5%; p < 0.0001) surgery. All new COVID-related measures are perceived to be maintained in the future. Surgeons' personal education online increased from 12.6% (pre-COVID) to 86.6% (post-COVID; p < 0.0001). Online educational activities are considered a beneficial effect from COVID pandemic (56.4%). COVID-19 had a great impact on surgical specialties, with significant reduction of operation volume. However, some forced changes turned out to be benefits. Isolation measures pushed the use of telemedicine and telemetric devices for outpatient practice and favored communication for educational purposes and surgeon-patient/family communication. From the Italian surgeons' perspective, COVID-related measures will continue to influence future surgical clinical practice

FUNCTIONALIZATION OF MONTMORILLONITE BY ACRYLAMIDE POLYMERS CONTAINING SIDE-CHAIN AMMONIUM CATIONS

Non-extractable poly(methyl methacrylate) (PMMA)-montmorillonite adducts were prepared by two distinct processes: (a) In the first method, free-radical copolymerization of MMA with clay previously treated with 2-(N-methyl-N,N-diethylammonium iodide) ethyl acrylate (QD1) or 2-(N-butyl-N,N-diethylammonium bromide) ethyl acrylate (QD4) was performed. (b) The second method was based on the direct interaction of montmorillonite with various copolymers of MMA with QD1 or QD4. The structure of the adducts as determined by Fourier-transform infra-red spectroscopy, thermogravimetric analysis and X-ray diffraction was shown to consist of the insertion of MMA macromolecules between lamellar layers whose separation was consequently higher than in the polymer-free clay. The polymer was strongly fixed to the inorganic surfaces, probably due to cooperative formation of electrostatic bonding. The thermal stability of the organic polymers was substantially enhanced in the adducts

New monodispersed palladium nanoparticles stabilized by poly-(N-vinyl-2-pyrrolidone): Preparation, structural study and catalytic properties

Mesitylene/1-hexene solvated palladium nanoparticles, obtained by metal vapour synthesis (MVS) technique, were stabilized in solution at room temperature with poly-(N-vinyl-2-pyrrolidone) (PVP) and isolated by precipitation with a diethyl ether or THF as brown powder. HRTEM and FT-IR analyses on samples with different Pd/PVP ratio (1%, 5%, 10%, 15%, 20 w/w%) showed palladium nanoparticles with mean diameters limited in the range 1.5–2.5 nm and the presence of competitive intermolecular interactions between C@O groups and palladium atoms on nanoparticle surface. The Pd–PVP systems, dissolved in EtOH solvent, showed excellent catalytic activity and selectivity in the hydrogenation of aliphatic alkynes (1-hexyne, 2-hexyne, 3-hexyne, 3-hexyne-1-ol) to the corresponding (Z)-alkenes. The catalytic activity of Pd–PVP samples, dissolved in 1-methyl-2-pyrrolidinone (NMP), has been also evaluated in the Mizoroki–Heck C–C coupling reaction of iodobenzene and bromo-arenes with butyl acrylate showing high efficiency. Moreover, the catalyst can be quantitatively recovered at the end of the reaction by precipitation with diethyl ether and reused without significant loss of catalytic activity

Fluorinated polymers as stone-protective materials: an FTIR study on intermolecular interactions

Attempts have been performed to obtain spectroscopic evidence of intermolecular interactions between fluorinated polymers to be used as protective materials and various stones. In this paper we report an investigation by means of FTIR spectroscopy on poly(vinyl fluoride)(PVF) which contains acid hydrogens that can give rise to intermolecular interactions with calcium carbonate. Spectral changes have been found in the C–H and C–F stretching regions at 3000–2840 and 1200–950cm−1, respectively. These last are attributed to intermolecular interactions of the polymer with CO3 2− and with conformational changes of the macromolecular chain. Scanning electron microscopy investigations were also performed on marble slabs coated with a PVF film in order to gain information about the morphology of the polymer film

An 8500-year-old bladder stone from Uzzo cave (Trapani): Fourier transform – infrared spectroscopy analysis

A calcium carbonate (calcite) bladder calculus was found in the pelvis of an adult female buried in a Mesolithic cave-tomb on the coast of Sicily; it was dated by14C to around 6500 bc. Its chemical composition, which was not known before, was determined by means of Fourier transform–infared microspectroscopy (FT–IR–M) using the high-pressure diamond cell, a device that makes it possible to analyse a small amount of the sample (1–2 µg). In this way, the analysis of all the laminations of the calculus was performed without destroying the sample. Although calcite was the main component, carbonate apatite was also detected in the nucleus and in a more external layer

Linear low-density polyethylenes by co-polymerization of ethylene with 1-hexene in the presence of titanium precursors and organoaluminium co-catalysts

The co-polymerization of ethylene with 1-hexene has been performed with titanium precursors based on carboxylato ligands in the presence of organoaluminium compounds as activators to afford linear low-density polyethylenes (LLDPEs). The influence of the polymerization parameters was studied with particular reference to the type and amount of catalyst components, solvent, temperature, ethylene pressure, 1-hexene concentration. The chloro-substituted bis-carboxylato titanium complex resulted the most active precursor in the co-polymerization, allowing to obtain copolymers with modulable composition in the 1-5 mol% range of 1-hexene units. The obtained copolymers were characterized by thermal analysis, X-ray diffraction spectroscopy, FTIR and NMR techniques. (c) 2007 Elsevier Ltd. All rights reserved