IR@CMERI - The Central Mechanical Engineering Research Institute (CSIR)
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Modeling of EHD inkjet printing performance using soft computing-based approaches
No full textNature-inspired heuristic and/or metaheuristic algorithms have been used for solving complex real-world problems in recent years. Electrohydrodynamic (EHD) inkjet printing is a microadditive manufacturing process in which high-resolution jets of polarizable functional materials were deposited on the defined spot of a substrate at the appointed time. The quality of the printed features is derived by the complex physics of the system. Parameter modeling of this process was carried out by using regression analysis, a feed-forward neural network trained with backpropagation (BPNN) and a neural network trained with a genetic algorithm (GA-NN) separately. This study emphasizes the droplet diameter prediction of an EHD inkjet printing system and explores the applicability of the soft computing-based methods for this new emerging technology. Soft computing-based approaches have been developed for the first time in this area to model the EHD inkjet process. Five hundred data were produced through the conventional regression analysis to train the neural network-based models. Output droplet diameter was predicted for different combinations of input parameters such as standoff height (SH), applied voltage (AV) and ink flow rate (FR) using the above three approaches, and their performances were analyzed through some randomly created real experimental test cases. All three models gave good prediction accuracy with less than 10% error in the prediction of the droplet diameter. Furthermore, it had been observed that the performance of GA-NN surpasses both the regression- and BPNN-based approaches in most of the test cases. It achieved quite satisfactory average absolute percentage deviation value of 2.51% between the target and predicted output using GA-NN model, which also showed an improvement over the regression or BPNN model
Tribological Property Investigation of Self-Lubricating Molybdenum-Based Zirconia Ceramic Composite Operational at Elevated Temperature
No full textThree mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) with 0.5 wt% of magnesium oxide (MgO) and 6 wt% of molybdenum (Mo) were prepared by the pressureless sintering process, and the friction and wear behavior of the ceramic composite were studied against the alumina disc. Tribological tests were carried out both at room temperature as well as at an elevated temperature (500 °C). The result revealed that a substantial reduction of ∼50% in the friction coefficient and ∼31% reduction in the wear rate were achieved while 6 wt% Mo was added into the 3Y-TZP matrix operational at 500 °C. No significant tribological influence was observed with the addition of Mo at the normal operating temperature. The minimum coefficient of friction and low specific wear rate were achieved because of the formation of MoO3 in between the mating surfaces at elevated temperature. The worn surfaces were characterized by means of field emission scanning electron microscopy (FESEM). The formation of MoO3 phases was identified by wear debris analysis which was performed with the help of X-ray photoelectron spectroscopy (XPS)
Investigation of electrochemical charge storage in nickel-cobalt-selenide/reduced graphene oxide composite electrode and its hybrid supercapacitor device
No full textNickel-cobalt chalcogenide-based composite materials were prepared by two-step hydrothermal technique. The change in morphology and crystalline phase of the materials with addition of 2D RGO sheet and exchange of anion by selenium was investigated. The alteration in electrochemical properties was also studied and correlated with the change in physicochemical properties. The electrochemical properties of the materials enhanced significantly when selenization occurred in presence of reduced graphene oxide (RGO) sheets. The NiCo2Se4/RGO (NCSG) electrode achieved highest specific capacitance of 1776 F g−1 at 2 A g−1 current density and retained excellent specific capacitance (51%) even at high (50 A g−1) current density. When the NCSG was integrated with sonochemically reduced graphene oxide (SRGO) and formed a hybrid supercapacitor (HSC) (SRGO//NCSG), the device delivered high specific capacitance of 212 F g−1 at 2 A g−1 current density. The HSC achieved a maximum energy density of 66.2 W h Kg−1 at 1500 W kg−1 power density, which is comparable or higher than those of other ternary metal selenide supercapacitors. The HSC exhibited the retention in specific capacitance of ∼93.5% after 5000 GCD cycles, confirmed the good stability and reversibility. These results promoted the NCSG/RGO composite as a new type of promising supercapacitor electrode material
Intracellular Fluorometric Recognition of Explosive and Mutagenic Nitroaromatics by a Luminescent Phenanthrene-Naphthalene Sulfone
No full textNovel phenanthrene-naphthalene sulfone based luminescent chemosensor has been synthesized for recognition of explosive and mutagenic 2,4,6-Trinitrophenolby fluorescence quenching with binding constant (1.93×105 M−1) and LOD (100 nM) that are better than reported sensory materials. Keeping in mind the toxic nature of 2,4,6-Trinitrophenol by, in vitro detection has been performed inside living organism like pollen cells of Tecoma Stans, Peperomia roots and Candida albicans.
Luminescent phenanthrene-naphthalene sulfone has been synthesized having phenanthrene and naphthalene as antenna center with an aim of fluorogenic in vitro detection of highly mutagenic NACs, which are hitherto less explored. The chemosensor could detect NACs selectively over NALs of which TNP detection is highly selective by a swing in fluorescence spectrum from 405 to ∼475 nm with extremely high quenching constant 1.93×105 M−1 and LOD 100 nM. Fluorometric recognition of TNP was explained through a combined complex PET-RET-ACQ-CT pathway. DFT calculation has been performed to obtain the low energy configuration of the host⋅⋅⋅guest adduct. NMR titration reveals the chemical stability of the host in presence of TNP, suggests that the interaction belongs to supramolecular realm that supports the utilization of the chemosensor forin vitro detection of TNP within pollens of Tecoma Stans, Peperomia roots and Candida Albicans, indeed establishes the scaffold as a biocompatible chemosensor
Pretreatment of polysaccharidic wastes with cellulolytic Aspergillus fumigatus for enhanced production of biohythane in a dual-stage process
No full textBiological pretreatment of polysaccharidic wastes (PWs) is a cost-effective and environmentally friendly approach to improve the digestibility and utilization of these valuable substrates in dual-stage biohythane production. In order to reduce the prolonged incubation time and loss of carbohydrate during the pretreatment of PWs with Aspergillus fumigatus, a systematic optimization using Taguchi methodology resulted in an unprecedented recovery of soluble carbohydrates (362.84 mg g−1) within 5 days. The disruption and fragmentation of lignocellulosic structures in PWs, and possible saccharification of cellulose and hemicellulose components, increased its digestibility. A dual-stage biohythane production with pretreated PWs showed increased yield (214.13 mL g−1 VSadded), which was 56% higher than the corresponding value with the untreated PWs. This resulted in 47% higher energy recovery as biohythane in pretreated biomass compared to untreated biomass. Optimized fungal pretreatment is, therefore, an effective method to improve the digestibility of PWs and its subsequent conversion to biohythane
Waste plastic to pyrolytic oil and its utilization in CI engine: Performance analysis and combustion characteristics
No full textFor application of pure plastic pyrolytic oil (PPO) several modifications in the engine is required which rejects the utilization of the existing engines while a blend of conventional fuel and PPO can be used with a slight change in engine without having a high impact on engine performance and hence the blends are preferred over the utilization of PPO as crude oil for diesel engines. In this study, the non-catalytic pyrolysis of mixed plastic waste at a temperature of 450 °C is done to obtain high-grade pyrolytic oil having a composition similar to petroleum fuels such as gasoline and diesel. Physical properties of the PPO were analysed, and the compound analysis was done with GC–MS. Further FTIR of PPO and diesel were analysed and compared. Five different ratios of 10, 20, 30, 40 and 50% PPO with diesel in blends were utilized as a fuel in a diesel engine to determine the engine performance and characteristics. The higher presence of PPO in blend increases the brake thermal efficiency (BTE) and reduces specific fuel consumption (SFC) with an increase in load as reported. The presence of PPO results in high heat release and delayed ignition resulting in high in-cylinder pressure. Further high amount of oxygenated compounds in PPO helps in reducing the emission from the combustion. The utilization of PPO with diesel upto 50% in the blend can be used in diesel engines with a slight increase in emission of CO at higher loads
Fast response and low temperature sensing of acetone and ethanol using Al-doped ZnO microrods
No full textWe report low temperature acetone and ethanol sensing properties of Al-doped ZnO microrods synthesized using hydrothermal technique. We observe the acetone detection at room temperature as well as ethanol and acetone detection at low temperature of 150 °C using Al-doped ZnO microrods. 3 wt% Al-doped ZnO microrods sensor exhibits the highest response of 231 toward 8100 parts per million (ppm) of ethanol at 150 °C. The response & recovery time are found to be ultrafast of 60 ms & 870 ms for ethanol and 110 ms & 330 ms for acetone of the Al-doped ZnO microrods at an operating temperature of 150 °C, respectively. In addition, sensing mechanism has explained to illuminate the improved sensing performances of Al-doped ZnO microrods. Thus it is revealed that Al-doped ZnO microrods are promising as an ultrafast gas sensor
Selection criteria of appropriate bamboo based biomass for thermochemical conversion process
No full textLignocellulosic biomass is carbon neutral and produces fuels and chemicals which are used for domestic, industrial, and transportation system. Thermochemical conversion processes (combustion, gasification, and pyrolysis) are emerging technologies which have great potential for industrial implementation. In this paper, the investigation has been done to select appropriate bamboo biomass suitable for thermochemical conversion process out of 21 biomass samples available in Mizoram, India. Various characteristics considered here for the selection of the appropriate bamboo biomass include proximate analysis, ultimate analysis, and their heating values. These characteristics are plotted in different diagrams and analysed in detail. It is observed after analysis that some bamboo biomasses are suitable combustion, some are suitable for pyrolysis and rest are suitable for gasification
Effect of indentation load on mechanical properties and evaluation of tribological properties for zirconia toughened alumina
No full textIn this study, co-precipitation processing route has been opted to prepare the ZTA composites. The well homogenized powders are compacted in a circular shape die-punch arrangement using hydraulic press. The mechanical properties of developed composites are evaluated on Vickers testing machine. In this study, a wide range of test load (0.5–50 N) has been applied on the samples to see it’s the effect on hardness. A significant decrease in the value of hardness and fracture toughness has been observed with increasing load. An interesting result has been observed beyond 25 N loads, where stagnation in the said properties is observed. After evaluation of mechanical properties the ZTA composites are used to investigate the tribological properties. A comparative study has been made between alumina and ZTA ceramics at a load of 20 N with sliding velocity of 0.5 m/s. The observed results show an improvement of 57.8% in case of specific wear rate, whereas 19.78% improvement has been achieved in case of coefficient of friction for ZTA ceramics as compared to alumina ceramics. The improvements in tribological properties are attributed to the soft phase of zirconia reinforced inside hard matrix of alumina which provides a toughening effect
Photocatalytic conversion of CO2 to methanol using membrane-integrated Green approach: A review on capture, conversion and purification
No full textIn the modern world, due to the ever increasing demand of electricity, industrialization and auto-mobilization, the abundance of greenhouse gases has shoot up to a critical level. A critical review has been initiated which provides a comprehensive literatures survey in the last two decades on the novel approaches available on different technologies for the anthropogenic CO2 capturing and conversion to methanol. In addition to that, merits and demerits of existing conventional technologies for downstream separation, purification and concentration enrichment of methanol have been discussed and compared with membrane-based system to find out the best optimal conditions. Extensive literature review reveals that the development of graphene based, TiO2/CuSO4 coupled photocatalyst for conversion of CO2 to methanol (33–37 mg/g catalyst) and downstream separation and purification using microfiltration membranes (Flux 100-110 L/m2h) stand out to be the best possible options for catalyst recycle and product recovery. In the previous studies the conversion was found as low as in the range of 10–20 mg/g catalyst without any development of hydrogen exfoliation graphene based nanocomposite material as well as any integration of spent catalyst recycle or product purification technology based on membrane separation. Such innovation and integration of process design employing cutting-edge schemes not only reduces the concentration of CO2 in biosphere but also produces renewable energy. These efforts towards green manufacturing while confirming the potentials of sustainable business is undeniably essential and should be stimulated