Journal of The Institution of Engineers (India): Series E

In this study, three different dyes, i.e., Punica granatum, Terminalia arjuna and Acacia catechu were used in combination with natural indigo dye. Pure cotton and pure silk mordanted swatches were first dyed by above three dyes and then re-dyed by indigo through vat method which gave beautiful shades of bluish green and shining dark green. It has also been observed that pre-mordanting with five different inorganic salts produced different shades after indigo dyeing. CIE La*b* and K/S values shown excellent reflectance on fabric. The light and washing fastness of the dyed samples were also evaluated, giving fair to excellent fastness grades especially the wash fastness after indigo dyeing gave very good results. It has been observed that combination of Punica, Acacia and Terminalia with Indigo has produced a diverse array of shades different from their intrinsic shades on both the fabric. Dyed fabric has shown substantial increase in color depth (K/S) and wash, light and rubbing fastness after indigo dyeing. The collection of shades and fastness grades may be useful for textile dyeing industry for cotton and silk fabrics.

Methyl benzoate (MB) is synthesized in a batch reactor conventionally and with the use of microwave (MW) energy as a source of heat. MW-assisted esterification has added advantage of competent energy use in volumetric region which provides a safe, economic and green method of heating. In microwave-assisted MB esterification, the amount of solvent is minimized. Also this work aims to study the product distribution and selectivity using heterogeneous zeolite Hβ catalyst. The esterification is studied by variation in operating conditions such as reaction time, feed composition, microwave energy and reaction temperature. It has been found that 88% conversion of BA with 74% selectivity of MB is formed using a conventional batch reactor, while with the use of MW energy as a source of heating, at 70 °C, 300 W MW power, 99.99% conversion of BA was achieved within 10 min with the highest selectivity of 86% using sulfuric acid and 67% of MB using Hβ catalyst, respectively.

The potential of using molecular sieves as adsorbent for the removal of nickel from aqueous solution was investigated. The isotherms and kinetics of nickel adsorption using 3 Å molecular sieves were evaluated. The results indicated that equilibrium was established in about 5 h. The effect of the pH was examined in the range of 2–6. The maximum removal of nickel obtained is at pH value of 5. The effect of dosage also evaluated to get optimum adsorption of nickel. The maximum adsorption capacity at 25 °C is 18.25 mg/g. The effect of temperature has been carried out at 15, 25, 30, and 40 °C. The data obtained from adsorption isotherms of nickel at different temperatures fit to linear form of Freundlich adsorption equation followed by Langmuir equations. Adsorption kinetic data were modelled using the pseudo-first and pseudo-second-order equation models. The results indicated that the pseudo-second-order model was best described adsorption kinetic data. The thermodynamic parameters such as enthalpy (ΔH°), free energy (ΔG°), and entropy (ΔS°) were calculated. They show that adsorption of nickel onto molecular sieves is an exothermic process. These results show that molecular sieves are a good adsorbent for the removal of nickel from aqueous solutions and could be used as a purifier for water and wastewater.

Co-gasification of petroleum coke with other carbonaceous material is making significant inroads in the quest for efficient utilization of petroleum coke. In the present work, gasification and co-gasification of petroleum coke and low-grade Indian coal was studied by thermogravimetric analysis at three heating rates, 10, 20, 30 °C min−1 under oxygen atmosphere. Physicochemical characterization of petroleum coke revealed that it contains significantly high fixed carbon and has high calorific value with low ash content vis-à-vis coal sample. It was observed that with the increase in heating rate, the ignition and the burn out temperature also increases. Kinetic parameters were calculated by employing commonly used two model-free isoconversional methods, i.e., Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO) based on TGA data. The activation energies of petcoke and blend (petcoke + coal) calculated by KAS and FWO methods were found to be 126.75 and 109.94 kJ mol−1, and 128.3 and 111.85 kJ mol−1, respectively. Activation energy values obtained by both the methods demonstrate that the blend requires lesser energy than gasification of petcoke alone. Gasification of blend was found to follow complex multi-step nature of kinetics. Overall, the findings demonstrate that co-gasification could be a practical approach for energy recovery from the petcoke–coal mixture than gasification of petcoke alone.

Air pollution is a global concern for human health. Air pollution leads to respiratory diseases, cancer, and even death. Tiny sized particulate matter (PM) and volatile organic compounds (VOCs) are the main health hazards in air. Functional nanofibres can trap these pollutants. This paper studied the electrospun nanofibre membrane (ENM) for protection against smaller PM (≤ 2.5 μm) and VOCs. The ENM of 1.2 g/m2 areal density was prepared using electrospinning. Due to the low ENM areal density, the air resistance was small, which makes it suitable for respiratory filtration. The ENM was characterised using scanning electron microscopy and capillary flow porometry. Its filtration efficiency and VOC adsorption capacity were determined using a typical laboratory set-up. The ENM showed excellent filtration efficiency (≥ 95%) for PM 0.3 μm. It also effectively adsorbed benzene VOC mainly due to its surface modification with β-cyclodextrin. The electrospun nanofibre membrane provides multifunctional protection and aids in pollution-free air breathing. This nanotechnology-based material has the potential to be used in air filtration for clean air.

Theoretical investigation on the process of development of warp yarn tension during weaving for tappet shedding is carried out, based on the dynamic nature of shed geometry. The path of warp yarn on a weaving machine is divided into four different zones. The tension developed in each zone is estimated for every minute rotation of the bottom shaft. A model has been developed based on the dynamic nature of shed geometry and the possible yarn flow from one zone to another. A computer program, based on the model of shedding process, is developed for predicting the warp yarn tension variation during shedding. The output of the model and the experimental values of yarn tension developed in zone-D i.e. between the back rest and the back lease rod are compared, which shows a good agreement between them. The warp yarn tension values predicted by the model in zone-D are 10–13 % lesser than the experimentally measured values. By analyzing the theoretical data of the peak value of developed yarn tension at four zones i.e. zone-A, zone-B, zone-C and zone-D, it is observed that the peak yarn tension value of A, B, C-zones are much higher than the peak tension near the back rest i.e. at zone-D. It is about twice or more than the yarn tension near the back rest. The study also reveals that the developed yarn tension peak values are different for the extreme positions of a heald. The impact of coefficient of friction on peak value of yarn tension is nominal.

Protease enzymes are extensively utilized in several industries ranging from pharmaceutical, food, biotechnology, cosmetics, leather, textile, dairy, and allied sectors. However, Plant rennet is in high demand in food and dairy industry due to several ethical, religious, and environmental causes. Jackfruit, pumpkin, and lotus seed extracts were tested for their milk clotting activities and found to have maximum milk clotting activity 2400MCU at their respective optimum conditions. Due to higher MCA milk curd were also tested for their potential use and found suitable for cheese preparation. Cottage cheese was prepared from all the plant extracts and for sensory analysis a panel of thirty volunteers were offered the sample and given the overall higher acceptability scores. In this view, more work is required, however an overall sensory acceptance suggested that these plant extracts can be used as an alternative to the animal rennet in dairy industry.