Insight on the influence of nano zinc oxide on the thermal,dynamic mechanical,and flow characteristics of Poly(lactic acid)– zinc oxide composites

Composites of Poly(lactic acid) (PLA) and spherical zinc oxide (ZnO) nanoparticles were prepared using melt processing followed by injection molding. The effect of nanosized ZnO on the molecular structure, thermal properties, dynamic mechanical properties, and flow characteristics of PLA composites were analyzed. Scanning electron microscopy images illustrated the formation of ZnO aggregates through PLA matrix. The molecular weight of PLA‐ZnO experienced a substantial decline by 55%, suggesting the presence of ZnO provoked degradation of PLA during composite preparation. Glass transition temperature of PLA‐ZnO decreased by 18% as compared with pure PLA, confirming the deleterious role of ZnO in PLA. The ZnO nanoparticles acted as a reactant and increased the thermal degradation rate. However, the incorporation of ZnO into PLA increased the crystallinity up to 20% and the storage modulus of composites in glassy state by 10%. The higher peak value of tan δ in composites suggested the more viscous behavior, which was further supported by lower number average molecular weight. The complex viscosity of composites exhibited a large Newtonian region over low shear rate, followed by shear thinning phenomenon. A significant decrease (96%) in complex viscosity was observed with the addition of ZnO into PLA. POLYM. ENG. SCI., 59:1242–1249 2019. © 2019 Society of Plastics Engineers     

Indoor inhalation dose estimates due to radon and thoron in some areas of South-Western Punjab, India

LR-115 (type II)-based radon-thoron discriminating twin-chamber dosemeters have been used for estimating radon ((222)Rn) and thoron ((220)Rn) concentrations in dwellings of south-western Punjab, India. The present study region has shown pronounced cases of cancer incidents in the public [Thakur, Rao, Rajwanshi, Parwana and Kumar (Epidemiological study of high cancer among rural agricultural community of Punjab in Northern India. Int J Environ Res Public Health 2008; 5(5):399-407) and Kumar et al. (Risk assessment for natural uranium in subsurface water of Punjab state, India. Hum Ecol Risk Assess 2011;17:381-93)]. Radon being a carcinogen has been monitored in some dwellings selected randomly in the study area. Results show that the values of radon ((222)Rn) varied from 21 to 79 Bq m(-3), with a geometric mean of 45 Bq m(-3) [geometric standard deviation (GSD 1.39)], and those of thoron ((220)Rn) from minimum detection level to 58 Bq m(-3) with a geometric mean of 19 Bq m(-3) (GSD 1.88). Bare card data are used for computing the progeny concentration by deriving the equilibrium factor (F) using a root finding method [Mayya, Eappen and Nambi (Methodology for mixed field inhalation dosimetry in monazite areas using a twin-cup dosemeter with three track detectors. Radiat Prot Dosim 1998;77(3):177-84)]. Inhalation doses have been calculated and compared using UNSCEAR equilibrium factors and by using the calculated F-values. The results show satisfactory comparison between the values.     

Soil clay mineralogy in relation to fertility management: Effect of soil clay mineral composition on potassium fixation under conditions of upland rice soils

Since K fixation in soils is largely a function of clay mineralogy, an effort was made to elucidate the influence of mineralogical variations in soil clays on K fixation, under the moisture-temperature regimes usually prevalent in tropical upland rice soils. Beidellitic clay turned out to be the most severe fixer of addedK (80%), followed by vermiculitic (69%) clays. Fixation is not appreciable (< 15%) in clays consisting of montmorillonite, x-ray amorphous material, chlorite, hydrous mica, kaolinite and halloysite. Fixation by beidellite and vermiculite clays is reduced by the simultaneous occurrence of other mineral species.     

Effect of bath ionic strength on adhesion and tribological properties of pure nickel and Ni-based nanocomposite coatings

The effect of electrolytic chemical concentration on wear-resistance, corrosion-resistance, adhesion and wettability properties of pure nickel and nickel–alumina composite coatings has been investigated in this paper. Coatings were electroplated over steel substrates under constant pulse conditions using pulse electrodeposition technique. Corrosion-resistance results show that the anti-corrosion properties are increasing with medium concentration (MC) both for pure nickel and nickel–alumina composite coating. For anti-wear properties, the MC showed increasing trend in case of pure nickel coatings but decreased in nickel–alumina composite coatings. In composite coating, the higher and low concentrations of electrolyte showed the higher wear resistance properties. Furthermore, the influence of electrolyte concentration on changing surface morphologies, mechanical, wettability and adhesion properties have been investigated and reported here. Surface morphologies of the synthesized coatings were studied with scanning electron microscopy (SEM) and energy-dispersive spectroscopy. Coatings surface mapping and wear analyses were examined by using 3D white light interferometry.     

Removal of surface reflection from above-water visible-near infrared spectroscopic measurements

Water quality estimation in fresh and marine water systems with in situ above-water spectroscopy requires measurement of the volume reflectance (rho(v)) of water bodies. However, the above-water radiometric measurements include surface reflection (L(r)) as a significant component along with volume reflection. The L(r) carries no information on water quality, and hence it is considered as a major source of error in in situ above-water spectroscopy. Currently, there are no methods to directly measure L(r). The common method to estimate L(r) assumes a constant water surface reflectance (rho(s)) of 2%, and then subtracts the L(r) thus calculated from the above-water radiance measurements to obtain the volume reflection (L(v)). The problem with this method is that the amount of rho(s) varies with environmental conditions. Therefore, a methodology was developed in this study for direct measurement of water volume reflectance above water at nadir view geometry. Other objectives of this study were to analyze the contribution of L(r) to the total water reflectance under various environmental conditions in a controlled setup and to develop an artificial neural network (ANN) model to estimate rho(s) from environmental conditions. The results showed that L(r) contributed 20-54% of total upwelling radiance from water at nadir. The rho(s) was highly variable with environmental conditions. Using sun altitude, wind speed, diffuse lighting, and wavelength as inputs, the ANN model was able to accurately simulate rho(s), with a low root mean square error of 0.003. A sensitivity analysis with the ANN model indicated that sun altitude and diffuse light had the highest influence on rho(s), contributing to over 82% of predictability of the ANN model. Therefore, the ANN modeling framework can be an accurate tool for estimating surface reflectance in applications that require volume reflectance of water.     

Wear and Friction Properties of Electrodeposited Ni-Based Coatings Subject to Nano-enhanced Lubricant and Composite Coating

This paper presents research findings on the tribological performance of electrodeposited coatings subject to nano-lubricants with the addition of nano-Al_2O_3 and graphene and Ni/nano-Al_2O_3 composite coatings. Electrodeposited coatings were produced by using a pulse electrodeposition method. Tribological experiments were conducted by using a linear reciprocating ball on flat sliding tribometer. Experimental results confirmed that the wear and friction resistance properties were significantly enhanced by doping of nano-effects in the lubricating oil and composite coating. The addition of Al_2O_3 nanoparticles in the lubricating oil showed the best tribological properties, followed by Ni–Al_2O_3 composite coatings and nano-oil with graphene. The surface morphology and microstructure of electrodeposited coatings were examined by scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction. The wear mechanisms of these coatings subjected to tribological testing were investigated by post-test surface analyses. This research provides a novel approach to design durable nano-coatings for tribological applications in various industries such as automotive,aerospace, locomotive and renewable energy technologies.     

Removal of heavy metals by adsorption on Pleurotus ostreatus

The present study explores the adsorption potential of Pleurotus ostreatus (a macro-fungus) to remove copper, nickel, zinc and chromium from water all together. Different operational parameters such as the effect of pH, biomass dose, equilibrium time, stirring intensity, temperature and initial metal ion concentrations were studied. Maximum adsorption of Ni(II), Cu(II) and Zn(II) took place in the pH range 4.5-5.0, whereas for Cr(VI) ion, best results were achieved at pH 2.5. Nearly 150 min are required to gain sorption equilibrium. Temperature has no significant effect on biosorption in the range of 20-45 °C. The maximum biosorption capacity of fungus was 8.06, 20.40, 3.22 and 10.75 mg g⁻¹ for Cu(II), Ni(II), Zn(II) and Cr(VI) in that order. FTIR analysis pointed out the involvement of amine (-NH₂) and carboxylic (-COOH) groups in the adsorption process. Simple and adjusted Langmuir and Freundlich isotherm models were used to explain the sorption phenomenon. For real effluents of electroplating, biosorption capacities were 2.73, 8.45, 0.88 and 4.45 mg g⁻¹ for Cu(II), Ni(II), Zn(II) and Cr(VI) ions, respectively. Moreover, used P. ostreatus was recycled repeatedly and used many times to evaluate the adsorption efficacy on reuse, but findings pointed out that capacity decreased, to some extent, on recycling.     

Techno‐mechanical properties of cocoon,raw silk and filament of two mulberry silkworm (Bombyx mori L.) strains

Natural silk is considered as queen of textile due to its superior traits. This study was conducted to assess technical properties of cocoon, and raw silk and mechanical properties of silk filament produced by two mulberry silkworm strains. The Chinese strain (205PO) produced dry cocoon of 0.61±0.04 g with raw silk of 0.30±0.02 g and the Japanese strain (J101) produced dry cocoon of 0.49±0.01 g with raw silk of 0.23±0.00 g. The single filament length of 205PO and J101 was 1203.1±20.42 m cocoon^?1 and 1082.3±48.95 m cocoon^?1, respectively. The filament was finer in the Japanese silkworm strain (1.91±0.06 denier) compared to the Chinese silkworm strain (2.26±0.15 denier). The filament tenacity, tenacity rupture and strain of J101 was 6.24 %, 24.62 % and 4.42 % greater compared to 205PO. The tensile strength of 205PO was 11.82 % greater compared to J101. The filament diameter was 22.01±0.42 μm and 21.98±0.15 μm of 205PO and J101, respectively. Based on these findings, it is recommended that silkworm strains with superior techno‐mechanical properties may be included in breeding programmes for enhancing the quality of silk textile.     

Physicochemical,melting and sensory properties of ice cream incorporating processed ginger (Zingiber officinale)

Ginger juice and paste (from 2 to 8%, ginger candy from 5 to 20%, and ginger powder from 0.5 to 2%) were incorporated into the ice cream mix prior to freezing. Inclusion of the juice and paste reduced total solids, fat, protein and overrun, and increased antioxidant activity and phenols, whereas the ginger candy and powder increased solids, crude fibre, antioxidant activity and phenols, and diminished fat and overrun. Acidity increased with the ginger juice and powder, whereas it decreased with the ginger paste and candy. First dripping time amplified and melting rate declined with all the ginger preparations. Ice cream containing ginger juice, paste, candy and powder at 6, 4, 10 and 1%, respectively, achieved the highest overall acceptability scores.