Aerosol characteristics during the coolest June month over New Delhi,northern India

June 2008, which is also the transition month between two major seasons for Indo-Gangetic Basin (IGB), has been identified the coolest June over New Delhi during the past century, showing mean temperature of 31.6 ± 1.7°C, which was found to be ～2°C less than its climatological mean (33.9°C). Aerosol optical properties for this month and thus obtained physical parameters have been studied using data from the CIMEL sun/sky radiometer, installed in New Delhi under the Aerosol Robotic Network (AERONET) programme. Results reveal bimodal aerosol volume size distribution. The monthly mean values for aerosol optical depth (AOD) at 500 nm (0.96 ± 0.31) and Ångström exponent at the wavelength pair of 440–870 nm (0.79 ± 0.42) show significant lower values whereas single scattering albedo at 675 nm shows a significantly larger value (0.94 ± 0.04) compared with previous measurements over the station. Results suggest dominance of scattering-type particles such as water-soluble aerosols from anthropogenic sources and dust aerosols from natural sources with higher relative humidity over the station. Radiative forcing caused due to the aerosols for the month of June 2008, which have been computed using the radiative-transfer model, informs low forcing at the top of atmosphere (TOA,?+14 W m^?2) as well as at surface (?33 W m^?2). The resultant atmospheric forcing (+47 W m^?2) indicates warming effect that caused heating of lower atmosphere at the rate of 0.89 K day^?1.     

A comparison among different modified Priestley and Taylor equations to calculate actual evapotranspiration with MODIS data

Priestley and Taylor's (1972) equation to estimate evapotranspiration (ET) stands for its simple form and data requirement. Although the original equation was developed for saturated surfaces, it has been widely extended to unsaturated surfaces. In this paper, different hypotheses to modify Priestley and Taylor's equation for unsaturated surfaces are compared. In general, ET models for unsaturated surfaces assume that the process is ruled by the available radiant energy and surface moisture or the atmospheric conditions or both surface and air states. The results presented here suggest that both atmospheric and surface variables should be jointly parameterized in order to obtain estimates with errors lower than 20%, which are common in ground observations. While surface condition parameterizations alone, such as those proposed by Barton (1979 Barton, I.J. 1979. A parameterization of the evaporation from nonsaturated surfaces. Journal of Applied Meteorology, 18: 43–47. [Crossref] , [Google Scholar]) and Jiang and Islam (2001 Jiang, L. and Islam, S. 2001. Estimation of surface evaporation map over southern Great Plains using remote sensing data. Water Resources Research, 37: 329–340. [Crossref], [Web of Science ®] , [Google Scholar]), show errors slightly larger than 20%, unaided atmospheric parameterization results in errors of about 50% of the mean ET. Our recently proposed model, with atmospheric and surface parameters, keeps the simple form of Priestley and Taylor's original equation while benefiting from remotely sensed data. Estimates with our model would have errors lower than 20%.     

Synthesis of novel bis- and tris-(cyclic carbonate)s and their use in preparation of polymer networks

Novel six-membered bis- and tris-(cyclic carbonate)s that are useful as cross-linking agents in the synthesis of structurally stable yet biodegradable polycarbonates and polyesters have been synthesized in good to moderate yield (85-45%). Cross-linked aliphatic polycarbonates, and polyesters were prepared by copolymerization of the bis-cyclic carbonate (3f) with trimethylene carbonate, and ε-caprolactone. The polymers swelled in a wide variety of organic solvents, including CHCl₃, CH₂Cl₂, ethyl acetate, acetone, DMSO, and DMF but not in protic polar solvents, such as methanol, ethanol, and water. Swelling ratios of trimethylene carbonate/3f and ε-caprolactone/3f networks at different feed ratios were investigated in dichloromethane. The glass transition temperature of the TMC/3f networks increased with increasing cross-link density.     

Effect of enrobing and antioxidants on quality characteristics of precooked pork patties under chilled and frozen storage conditions

Enrobed or coated pork patties containing a (50:50) mixture of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) at a level of 100 ppm in the batter mix and meat emulsion were cooked and stored chilled (4±1?°C) and frozen (-18±1?°C) for evaluation of quality. Test samples were compared to control patties (neither enrobed nor antioxidant treated). After 35 days of refrigerated storage no significant difference (P>0.05) was found in pH, 2-thiobarbituric acid (TBA) and Warner-Bratzler shear force (WBSF) values between uncoated and treated samples. Similarly, enrobed patties showed no significant (P<0.05) decrease in TBA values compared to control patties, but had lower relative moisture loss at the 45th day of frozen storage. However, control patties had significantly (P<0.05) higher overall shear values than coated patties under the same storage conditions. Coated samples had higher microbial loads but below the acceptable limit. Total plate counts (TPC) in enrobed and control patties were around 3.48 and 3.05 log(10) cfu/g, respectively, whereas in frozen stored samples these numbers were 2.77 and 2.69 log(10) cfu/g at the end of storage. Sensory scores viz appearance and color, flavor, juiciness, texture, and overall acceptability were higher in treated samples than controls during the entire storage period.     

pH-Controlled association of PEG-containing terpolymers of N-isopropylacrylamide and 1-vinylimidazole

Temperature- and pH-controlled association of terpolymers of N-isopropylacrylamide (NIPA) with 1-vinylimidazole (VI) and polyethylene glycol (PEG) has been investigated by light scattering and atomic force microscopy (AFM) in situ. The polymers contained 0-15 mol% VI and 0-2 mol% PEG. The phase transition temperatures (T_p) have been in the range of 32-45 °C and exhibited significant dependence on the pH of solution in the pH range between 5 and 8. The T_p of the polymers increased with increasing VI content and with decreasing pH, confirming major effect of VI ionization status on T_p. The presence of PEG grafts in the polymer structure had augmenting effect on the magnitude of pH-responsiveness and on the pH-independent colloidal stability of the polymer particles formed above T_p. Incorporation of VI into the polymer structure had similar, but pH-dependent effect on colloidal stabilization of the polymer particles. The size of the particles formed after the phase transition is driven by the association of the collapsed NIPA segments in the globule conformation and it decreased with decreasing pH. The phase transition temperature of the polymers could be adjusted to increase from temperatures below, to temperatures above body temperature upon decreasing pH from 7 to 6, suggesting that such polymers could provide a material platform for a variety of biomedical applications. AFM analysis in situ showed a fully reversible formation of particles in the solutions of the polymers above their T_p.     

Physico‐Mechanical and Antibacterial Properties of Pine Gum/Epoxy Composites with/without Silver Nanoparticles

Silver nanoparticles/polymer composite (Ag‐NPs/PC) may eventually be biodegradable, sustainable, or burned without production of lethal by‐products and can be utilized as packaging and biomedical device applications. Nanoparticles engaged in pine gum (resin and rosin) are preserved for months without any significant effect on particle size and distribution. This paper focuses on the pine gum/epoxy composites with and without silver nanoparticles fabricated by a hand lay‐up technique. Silver nanoparticles are fixed at 0.37% and pine gum varies from 2 to 24% by weight to acquire the best mechanical and wear properties. The result indicates that Ag‐NPs with pine gum (23.7 wt% resin &13.3 wt% rosin) has the best tensile and impact strength reaching a gain of 51.34% and 53.68% simultaneously. Hardness is noted most extreme 17.92% at Ag‐NPs sample (7.4 wt% resin and 3.7 wt% rosin) and wear resist behavior is best noted with neat pine gum/epoxy composite. The antibacterial assay of the Ag‐NPs is done against Escherichia coli and noted that the zone of inhibition is found to be 1.6 cm as compared to inhibition of 0.4 cm for pine gum reaching an advance of 75%. The various arrangements are enhanced and sited on the basis of TOPSIS technique.     

Microwave-assisted synthesis of α-Fe2O3/ZnFe2O4/ZnO ternary hybrid nanostructures for photocatalytic applications

Solar-driven highly efficient photocatalytic decomposition of toxic organic contaminants using magnetically separable α-Fe₂O₃/ZnFe₂O₄/ZnO ternary hybrid nanodiscs is reported. α-Fe₂O₃/ZnFe₂O₄/ZnO ternary hybrid nanostructures were synthesized by microwave-assisted co-precipitation and simple co-precipitation methods and well characterized by XRD, micro-Raman, FESEM and UV–vis spectroscopy. FESEM micrographs revealed nanodiscs in case of microwave-assisted co-precipitation whereas nanoparticles and their aggregates were formed under co-precipitation combined with calcination. XRD and Raman studies confirmed the hybrid nature of prepared α-Fe₂O₃/ZnFe₂O₄/ZnO nanostructures. Photocatalytic performance of α-Fe₂O₃/ZnFe₂O₄/ZnO hybrid nanostructures was investigated by carrying out the photodegradation of organic dyes MB and MG under solar light illumination. The prepared α-Fe₂O₃/ZnFe₂O₄/ZnO ternary hybrid magnetic nanodiscs decomposed MB and MG dyes in only 32 and 24 min, respectively. α-Fe₂O₃/ZnFe₂O₄/ZnO hybrid nanodiscs showed excellent photocatalytic performance together with reusability and easy magnetic separation demonstrating its suitability for solar-driven photocatalytic water purification applications. In-situ scavenger studies showed ?OH radicals are the main active radicals in solar-driven photocatalysis by α-Fe₂O₃/ZnFe₂O₄/ZnO nanodiscs. The tentative mechanism of growth of α-Fe₂O₃/ZnFe₂O₄/ZnO ternary hybrid nanodiscs and the photocatalytic mechanism are discussed.     

Recent Developments in Spatio-Temporal EEG Source Reconstruction Techniques

EEG is gaining recognition in the field of real-time applications. However, the EEG inverse problem leads to poor spatial resolution in brain source localization. This paper presents an overview of the existing EEG inverse solution methods. Further, a comparative analysis of recent techniques has been presented. This work discusses the challenges associated with the existing source reconstruction algorithms. The main focus is on the recent reports in this field that have combined the EEG denoising in the pre-processing phase along with the inverse localization approaches. Out of various existing techniques, SLORETA offers better localization results but its noise sensitivity is very high. It has been validated in a comparative analysis for simulated dipole sources with no noise. To illustrate the advantage of using pre-processed data with inverse localization, the classification accuracy of conventional methods has been compared. The accuracy has been analyzed for depression signals using the Naïve Bayes, RF, and SVM classifiers. The VMD- SLORETA method shows better accuracy as compared to EMD-SLORETA and SLORETA only. The existing EEG localization methods are efficient but the spatial resolution is still to be improved in the presence of various noise sources in raw EEG. More accurate localization is achieved by implementing denoising in combination with the source localization framework. There is a need to investigate further stages of EEG signal processing along with optimal feature selection. Further, additional studies should be conducted to improve the noise sensitivity of other existing localization systems using pre-processing approaches.

Graphic Abstract

     

A laboratory technique for the evaluation of automotive gear oils of API GL-4 level

Automotive gear oils, as typically used in rear axles, are normally evaluated in terms of their performance in full-scale bench tests. One such test is the CRC L-19/CRC L-42 test, which is included in API and other specifications. The L-19 test method is now obsolete, and the L-42 is used basically to define GL-5 level oils. An indigenous test method, IIP Method VAV-382, has been developed at the Indian Institute of Petroleum on an Amsler machine, operating under sliding conditions between two discs, and is also included in the IS:1118-92 specification for multi-purpose gear oils for GL-4 level oils. This method has been re-examined to obtain better resolution of scuffing of the disc surfaces. The modified procedure has proved effective, and the procedure and results for various commercial oils are described in this paper, which shows the method to be effective for the evaluation of GL-4 level oils.