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10% Calcium-doped ceria (CCO) nanoparticles have been synthesized by sol–gel method. Their surface has been modified by surfactants, sodium dodecyl sulfate and 1-decyl-3-methyl imidazolium bis(trifluoromethyl sulfonyl) imide to yield SCCO and IL-CCO respectively. Powder X-ray diffraction patterns of nanoparticles and surface modified nanoparticles are indicative of cubic phase of ceria. Fourier transform infrared spectra confirm the surface modification of nanoparticles, particularly with ionic liquid. Morphology of the as-prepared nanoparticles investigated by field emission scanning electron microscopy, transmission electron microscopy/high-resolution transmission electron microscopy reveals that there is decrease in size of nanoparticles from CCO followed by SCCO and then IL-CCO. Wrapping of nanoparticles by ionic liquid is apparent in the scanning electron microscopy (SEM) and transmission electron microscopic (TEM) images. The tribological activity of the well-characterized nanoparticles has been evaluated at the optimized concentration, 0.2% w/v in paraffin oil under ASTM D4172 and ASTM D5183 test conditions using a four-ball tester. Based on tribological parameters, mean wear scar diameter, average friction coefficient, load-carrying capacity, and loss of frictional power, their relative performance followed the order – IL-CCO > SCCO > CCO. Worn surface analysis by scanning electron microscopy/energy-dispersive X-ray spectroscopy, atomic force microscopy corroborated the tribological performance. The order of the activity could be correlated with the size of the nanoparticles. Moreover, lubricating properties of ionic liquid have been instrumental for the exalted activity of IL-CCO. The presence of heteroatoms of ionic liquid, nitrogen, oxygen, fluorine, sulfur along with calcium and cerium of nanoparticles in energy-dispersive X-ray (EDX) spectroscopy analysis of the wear scar surface lubricated with IL-CCO confirms the vital role of ionic liquid towards the tribological activity. [ABSTRACT FROM AUTHOR]

Carbon nanospheres, copper nanoparticles and their composite Cu@C having copper nanoparticles embedded in carbonaceous material were synthesized hydrothermally. The analytical techniques; powder X-ray diffraction(XRD), field emission scanning electron microscopy(FE-SEM) with energy-dispersive X-ray spectroscopy(EDX), transmission electron microscopy/high- resolution transmission electron microscopy(TEM/HR-TEM), Raman and X-ray photoelectron spectroscopy (XPS) have been employed for their characterization. Tribological behavior of blends of the synthesized additives with paraffin oil has been investigated on a four-ball lubricant tester using ASTM D4172 and ASTM D5183 at 0.1% w/v concentration. Comparative activity of the base oil and the blends has been adjudicated considering the experimental data for mean wear scar diameter (MWD), coefficient of friction (COF), load-carrying capacity and wear rates collected from the above standard tests. The admixture-containing nanohybrid, Cu@C appears to show the best activity followed by that of copper nanoparticles and then carbon spheres. The relative activity of different admixtures is verified by atomic force microscopy(AFM) and scanning electron microscopy(SEM) with EDX results of the wear pathway. The EDX spectrum of Cu@C shows the existence of copper together with carbon on the wear scar surface confirming their contribution in the formation of in situ tribofilm. Thus, these additives may be approved for enhancing lubrication. [ABSTRACT FROM AUTHOR]

Antiwear properties of metal and sulfur-free synergistic formulations containing quinoline derivatives (QDs)—4-N-(7-chloroquinolin-4-yl)-1-N,1-N-diethylpentane-1,4-diamine (QD-1), 4-N-(6-methoxyquinolin-8-yl)pentane-1,4-diamine (QD-2) and 1-N,1-N-diethyl-4-N-(6-methoxy quinolin-8-yl)pentane-1,4-diamine (QD-3)—with triphenyl phosphate (PE) in polyethylene glycol (PEG) at a very low concentration, 0.25% w/v of each, have been studied on a four-ball tester using ASTM D4172 and D5183 standards. Phosphorus content in the formulations was significantly reduced compared to the frequently used antiwear additive zinc dialkyldithiophosphate (ZDDP) and it was much lower than the allowed concentration suggested by various norms. The synergistic admixtures, SQD-2 and SQD-3, significantly improved the antiwear properties of base lube compared to the ZDDP/PE/QDs alone but the behavior of SQD-1 is comparable to that of ZDDP. Minimum values of mean wear scar diameter and average coefficient of friction were found to be 0.458 mm and 0.034, respectively, for SQD-3, the admixture with the maximum antiwear efficiency. However, these values were 0.538 mm and 0.083, respectively, for ZDDP, and for base oil the values were 1.185 mm and 0.126, respectively. The load-carrying capacity was found to be much higher for the synergistic formulations than for ZDDP. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) micrographs of the wear track support the tribological behavior of the above additives. The presence of nitrogen, oxygen, and phosphorus in energy-dispersive X-ray (EDX) spectra of the worn surface lubricated with SQDs indicates the adsorption of additive on the surface. The magnificent tribological behavior of SQDs may be attributed to the tribochemical film formed on the steel surface invoking phosphorus–nitrogen synergy. Quantum chemical calculations (density functional theory) for interactions of QDs with a steel surface agree well with the experimental observations. [ABSTRACT FROM AUTHOR]

Schiff base derived from condensation of 4-aminotriazole with indole-3-carboxylaldehyde has been characterized by Fourier-transform infrared and 1H NMR spectroscopic techniques. The tribological properties of synthesized Schiff base have been evaluated using four-ball tester at optimized concentration (1% w/v) and compared with its individual components. The tribological testing has been performed by varying load for 30 min duration and varying test durations at 392 N load. The synergistic action of Schiff base with commercial borate ester effectively enhances the antiwear properties of base oil and its load-carrying capacity. Pronounced reduction in the values of mean wear scar diameter, friction coefficient (µ), mean wear volume (MWV), and wear rates confirm the synergistic interaction between Schiff base and borate ester. The best tribological properties are shown by synergistic mixture, followed by Schiff base, then indole-3-carbaldehyde, and finally 4-aminotriazole. The surface topography of worn surfaces has been studied by scanning electron microscopy and contact mode atomic force microscopy which show the drastic decrease in surface roughness in the presence of synergistic mixture. The energy-dispersive X-ray analysis of worn surface lubricated with synergistic formulation exhibits nitrogen, carbon, boron, and oxygen indicating the adsorption of additive on the metal surface to form in situ protective tribofilms, which prevent direct metal–metal contact thus reducing friction and wear. The quantum chemical calculations studies show that there is significant interaction of Schiff base additive with the metal surface than those of its individual components and the data correlate very well with the obtained tribological results. [ABSTRACT FROM AUTHOR]

For developing antiwear additives with high efficiency but with low sulfated ash, phosphorous, and sulfur (SAPS), N-substituted quinolinium halides, [DIP-Q]+Br−[DIP-Q=1-(3-(1,3-dioxoisoindolin-2-yl)propyl)quinolon-1-ium], [DIE-Q]+Br−[DIE-Q=1-(3-(1,3-dioxoisoindolin-2-yl)ethyl)quinolon-1-ium], [P-Q]+I−[P-Q=propylquinolon-1-ium], and [M-Q]+I−[M-Q=methylquinolon-1-ium] have been prepared and characterized by1H- and13C-NMR spectroscopic techniques. The tribological performance of these quinolone-based quaternary salts as antiwear additives in paraffin oil has been assessed on a four-ball test rig. The observed results have been compared with those of zinc dialkyldithiophosphate (ZDDP), a high SAPS additive. The tribotesting of these additives has been performed using 1% w/v additives concentration at different loads and times. The potential of these compounds as antiwear additives is evident from their observed tribological data: mean wear scar diameter (MWD), friction coefficient (µ), mean wear volume (MWV), and wear rates. All of the quinolinium derivatives prove to be better antiwear additives than ZDDP. Among the tested synthesized compounds, [DIP-Q]+Br−exhibits the best tribological behavior followed by [DIE-Q]+Br−, [P-Q]+I−, and [M-Q]+I−. The surface topography of worn surface studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM) shows that surface roughness is reduced to a greater extent in case of quinolinium derivatives than lubrication with ZDDP or base oil alone. Energy-dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) analysis of worn surfaces in the presence of quinolinium additives shows that the tribofilm is composed of FeBr3, Fe3O4, and organic compounds containing carbonyl and imine bonds. Theoretical investigations using quantum chemical calculations are indicative of significant chemical interactions of these quinolinium additives with metal surfaces, which is strongly supported by the observed experimental data. [ABSTRACT FROM PUBLISHER]

Antiwear behavior of lanthanum Schiff bases of the formula LaLNO3 (where LH2 = Salicylidene-1,2-phenylenediamine(H2Saloph), Salicylidene-1,4-phenylenediamine(H2Salpph), Salicylidene diaminodiphenylenemethane(H2Saldphm)) has been studied on Four-Ball tester in paraffin oil. The results have been compared with zinc dibutyldithiophosphate (ZDDP) and organoborate (Vanlube 289). The additive concentration was optimized by conducting tests for different concentrations 0.5, 1.0, 1.5, and 2% w/v of the additives at 392 N applied load for 30-min duration. All the antiwear tests have been performed at optimized additives concentration (1% w/v) by varying loads from 294, 392, 490, 588, to 686 N for 30-min test duration and by varying test duration from 15, 30, 60, and 90 min at 392 N load. The determined tribological parameters show that all complexes act as good antiwear additives. Their activity is even better than ZDDP/borate ester. When mixtures of complexes with Vanlube 289 are tested, tremendous synergistic interaction is observed. Out of the three tested complexes, [La(Saldphm)NO3] shows excellent antiwear properties and possesses very high load-bearing capacity. Surface morphology of worn scar has been studied by scanning electron microscopy and atomic force microscopy. These micrographs of wear scar in the presence of [La(Saldphm)NO3] at 392 N applied load for 90-min duration show drastic increase in surface smoothness. Energy dispersive X-ray analysis of worn surface under similar experimental conditions in presence of the above complex exhibits presence of lanthanum on steel surface indicating adsorption of additive on rubbing surface, which leads to the formation of strong tribofilm. Further, X-ray Photoelectron Spectoscropy (XPS) of the tribofilm shows presence of adsorbed nitrogen and mixture of oxides B2O3, La2O3, Fe2O3/Fe3O4. [ABSTRACT FROM AUTHOR]

Recently, the apex environmental agency of India observed that domestic industrial pollution has been increasing at an alarming rate over the last two decades, and the need to rein in traditional polluting industries. This raises the pertinent question of whether the poor domestic pollution regime has affected the pattern of India's trade in dirty manufactured products in the post-liberalisation era since 1991. We find that on the whole, India has remained a net importer of pollution-intensive manufactured goods; however, there is a distinct trend of increasing specialisation in specific dirty industries especially in the bilateral trade with high-income countries, and to a lesser degree with low-income countries. The USA being India's single largest country trading partner in the post-liberalisation era, we test for pollution offshoring at the finer industry level in US-India bilateral trade. While we find that the pollution haven effect is not significant, India's specialisation in certain dirty manufacturing industries through the last decade remains a disturbing trend. India needs to integrate environmental sustainability within industrial growth urgently, and it is pertinent to implement policies which would reflect the true pollution costs in an industry that is increasingly competing in the international market. [ABSTRACT FROM AUTHOR]

To correlate antiwear properties of Schiff bases derived from condensation of salicylaldehyde with 1,2-phenylenediamine, [2,2′-(1,2-phenylenebis(azan-1-yl-1-ylidene))bis(methan-1-yl-1-ylidene)diphenol; H2Saloph], 1,4-phenylenediamine [2,2′-(1E,1′E)-(1,4-phenylenebis(azan-1-yl-1-ylidene))bis(methan-1-yl-1-ylidene)diphenol; H2Salpph] and 4,4′-diaminodiphenylmethane, [2,2′-(1E,1′E)-(4,4′-methylenebis(4,1-phenylene)bis(azan-1-yl-1-ylidene)diphenol; H2Saldphm] with their chemical structures, quantum chemical calculations based on density functional theory have been performed. The interaction between the additive molecules and metal surfaces has also been discussed. In order to compare the antiwear behavior, various parameters such as frontier molecular orbital energy, energy of highest occupied molecular orbital, energy of lowest unoccupied molecular orbital, energy gap and Mulliken charges have been calculated. The quantum chemical calculations have shown that wear reducing behavior of Schiff bases increases with increase in energy of highest occupied molecular orbital, decrease in energy of lowest unoccupied molecular orbital and also decrease in energy gap between energy of lowest unoccupied molecular orbital and energy of highest occupied molecular orbital of the additives. The quantum chemical calculations results have been found to be in good agreement with those of experimental results. [ABSTRACT FROM PUBLISHER]

Stearic acid modified ceramic nanoparticles SCCZTO-6 h, SCCZTO-8 h and SCCZTO-12 h of average sizes 60, 80 and 90 nm were prepared from CCZTO-6 h, CCZTO-8 h and CCZTO-12 h respectively (where CCZTO represents CaCu2.9Zn0.1Ti4O12; 6 h, 8 h and 12 h are the sintering times). The SCCZTO nanoparticles have been characterized by Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). Tribological behavior of these nanoparticles in liquid paraffin oil has been evaluated using a four-ball lubricant tester and compared with conventional high SAPS containing zinc dialkyldithiophosphates (ZDDP). All antiwear tests have been performed using an optimized concentration of the SCCZTO nanoparticles (1% w/v) by varying the load for a 30 min test duration and by varying the test durations at 392 N load. Various tribological parameters such as mean wear scar diameter (MWD), friction coefficient (μ), mean wear volume (MWV), running-in, steady-state and overall wear rates show that all the SCCZTO nanoparticles act as efficient antiwear additives and possess a high load carrying capacity. The best tribological behavior is shown by SCCZTO-6 h, followed by SCCZTO-8 h and then SCCZTO-12 h. The surface morphology and roughness of the wear scar have been studied by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) respectively. AFM and SEM micrographs of the wear scar in the presence of SCCZTO-6 h and SCCZTO-8 h at 392 N applied load for a 90 min test duration show a drastic decrease in surface roughness. Energy-Dispersive X-ray (EDX) analysis of the worn surface under similar experimental conditions in the presence of SCCZTO-6 h nanoparticles exhibits the presence of calcium, copper, zinc, titanium and oxygen on the worn steel surface indicating tribosinterization and/or adsorption of the additive on the rubbing surface resulting in the formation of a strong tribofilm. X-ray Photoelectron Spectroscopy (XPS) of the tribofilm shows the presence of CaO, CuO, Cu2O, TiO2, Fe2O3 and adsorbed carbon in the form of –C–C– and –C(O)O– moieties. [ABSTRACT FROM AUTHOR]

Antiwear properties of zinc(II) complexes of salicylaldehyde N(4)-phenyl-p-substituted thiosemicarbazones and their synergic action with Vanlube 289 additive were evaluated in paraffin oil on four ball tester using steel balls of 12.7 mm diameter and the results were compared with those of zinc dibutyl dithiophosphate. On the basis of mean wear scar diameter, mean wear volume, friction coefficient, running-in and steady-state wear rate under optimum conditions, the following order of efficiency emerged: Zinc(II) thiosemicarbazones + Vanlube 289 > Vanlube 289 > ZDDP > Zinc(II) thiosemicarbazones. Among the zinc(II) complexes alone or their synergic formulations, salicylaldehyde N(4)-p-methoxyphenylthiosemicarbazones [Zn(HSTC-p-OMePh)2] exhibits best antiwear properties followed by salicylaldehyde N(4)-p-chlorophenylthiosemicarbazone [Zn(HSTC-p-ClPh)2], salicylaldehyde N(4)-p-methylphenylthiosemicarbazone [Zn(HSTC-p-MePh)2] and salicylaldehyde N(4)-p-phenyl thiosemicarbazones [Zn(HSTC-Ph)2] derivatives. The topography of the wear scar studied by atomic force microscopy and scanning electron microscopy in absence and presence of the additives indicated reduced roughness of the surface in presence of the additives. The admixtures containing zinc(II) complexes and their synergic formulations with Vanlube 289 showed presence of sulfur, nitrogen, oxygen and zinc in the energy-dispersive X-ray analysis of the wear scar. [ABSTRACT FROM PUBLISHER]