Microwave-assisted polycrystalline Ag/AgO/AgCl nanocomposites synthesis using banana corm (rhizome of Musa sp.) extract: Characterization and antimicrobial studies

Krishna Kumar Jaiswal,Ishita Banerjee,Swapnamoy Dutta,Ravikant Verma,Lokanadhan Gunti,Sharad Awasthi,Mayank Bhushan,Vinod Kumar,Mohamed Fahad Alajmi,Afzal Hussain 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.107 No.-

The rapid emergence of multidrug-resistant microbes has turned into the main threat to public healthworldwide. The preparation and application of nanomaterial-based antimicrobials have increased toaddress this problem with great significance. This study has investigated the bio-fabrication of polycrystallineAg-NCs using BCE as a reducer and stabilizer under microwave irradiation. Ag-NCs formationswere optimized using varying concentrations of BCE and silver acetate. The XRD confirmed the incidenceof phases of nanostructured crystals of Ag/AgO/AgCl. The average crystallite sizes were calculated to be22.19, 36.65, and 36.65 nm for Ag, AgO, and AgCl, respectively. SERS spectra revealed the vibrationalmodes of the Ag and Ag-O stretch bands. FTIR spectra have indicated the incidence of chemical fingerprintsfor Ag-NCs and BCE biomolecules. SEM and HR-TEM micrographs exhibited the almost sphericalto the oval shape of 50 nm. SAED pattern attested to silver crystallinity in agreement with XRD analysis. The MIC values of the Ag-NCs against Escherichia coli, Staphylococcus aureus, Aspergillus brasiliensis, andRhizopus stolonifer were observed to be 120, 60, 200, and 100 mg/ml, respectively. This study has demonstratedthe facile method to prepare polycrystalline Ag-NCs with appropriate structural and morphologicalcharacteristics for antimicrobial applications.

Insight into emerging applications of forward osmosis systems

Pallabi Das,Krishna Kant Kumar Singh,Suman Dutta 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.72 No.-

The advent of Forward Osmosis (FO) has ushered in a new revolution in thefield of membranetechnology. Besides the oft-studied application of water purification, FO has opened up new frontiers ofresearch in diversefields. All of them are potentially sustainable technology solutions characterized by ahigh degree of process intensification. It is interesting to imagine different avenues where the potentcombination of membrane technology and osmotic gradient can be used. This brief review evaluates foursuch emerging applications of FO; viz: Membrane Crystallization, Osmotic Pumps, Energy Production,and Membrane Evaporation which will be considered as the most important in the near future. All fouraforesaid applications were critically reviewed with respect to the principle of operation, process designfundamentals, cost distribution, tangible benefits over conventional alternatives and commercialventures around the world. Comparative assessments of transportflux, yield, configuration, andmembrane module was carried out. Several issues relating to performance, hydrodynamics and scale updesigns were analyzed with special emphasis on concentration polarization,flux decline, nature of themembrane.

A Comprehensive Study on Solid Waste Vehicle Routing and Tracking – a Case Study on Kolkata City

Koushik Paul,Amit Dutta,Akhouri Pramod Krishna 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.1

Kolkata city generates about 3500 Metric Ton (MT) of solid waste per day. Waste collected at storage vats/containers is transported to disposal ground at Dhapa by Kolkata Municipal Corporation (KMC) departmental vehicles and hired vehicles. Collection, segregation and transportation of municipal solid waste in KMC area is unplanned and chaotic; there is no uniformity in the size of containers/open vats and the size and haulage capacity of transport vehicles. The operational efficiency of KMC transport system is about 50%, with a fleet composed of 30-35% old vehicles. KMC spends 70-75% of its budget on collection of solid wastes, 20-25% on transportation and less than 5% on disposal. KMC allocates different types of collection vehicles to different types of containers/ open vats depending on waste generation at a location and compatibility of the vehicles with the storage receptacles. It was, thus, a challenge to present an acceptable, realistic solution optimising the waste vehicle routes, thus cutting down on the transportation costs and increasing overall efficiency. ArcGIS Desktop has been used to determine least cost paths for collection and transportation of wastes; while low-cost tracking methods has been attempted using ArcGIS and Garmin 72H GPS set.

Fatigue Properties of Resistance Spot Welded Dissimilar Interstitial‑Free and High Strength Micro‑Alloyed Steel Sheets

Gorti Janardhan,Kaushal Kishore,Goutam Mukhopadhyay,Krishna Dutta 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.9

This study aims to investigate the influence of nugget diameter on tensile-shear and fatigue properties of the dissimilar resistancespot-welded joints of interstitial free and high strength niobium microalloyed steel sheets. The spot-weldings are doneat currents of 7 kA and 9 kA at welding time of 300 ms with electrode force of 2.6 kN. Fatigue tests are done at different loadamplitudes, considering the maximum tensile-shear load bearing capacity of the joints. The tests are interrupted before thefinal failure to understand the crack initiation and propagation paths. The study is supplemented by the microstructural anddetailed fractographic analyses. The results indicated that the fatigue strength of the spot-welds increased with a decrease innugget diameter. This could be attributed to the higher microhardness of heat affected zone (HAZ), presence of compressiveresidual stress and lower variation in thickness reduction on the IF steel side, welded at 7 kA. However, the tensile-shearload bearing capacity of the spot-welds increased with increase in the nugget diameter. The failure of the spot-welded jointunder static loading initiates from the HAZ/base metal interface of the IF steel side. Nevertheless, under cyclic loading crackinitiates from the notch root at the interface of two sheets lying in the HAZ of IF steel side. Fractographic investigationsindicate intergranular fracture features in combination with striations, secondary cracks on the IF steel side under cyclicloading. Fracture surfaces of the specimens failed under static loading shows however, shear dimples on the IF steel side.

A comprehensive optimization model for integrated solid waste management system: A case study

Koushik Paul,Subhasish Chattopadhyay,Amit Dutta,Akhouri P. Krishna,Subhabrata Ray 대한환경공학회 2019 Environmental Engineering Research Vol.24 No.2

Solid waste management (SWM) is one of the poorly rendered services in developing countries – limited resources, increasing population, rapid urbanization and application of outdated systems leads to inefficiency. Lack of proper planning and inadequate data regarding solid waste generation and collection compound the SWM problem. Decision makers need to formulate solutions that consider multiple goals and strategies. Given the large number of available options for SWM and the inter-relationships among these options, identifying SWM strategies that satisfy economic or environmental objectives is a complex task. The paper develops a mathematical model for a municipal Integrated SWM system, taking into account waste generation rates, composition, transportation modes, processing techniques, revenues from waste processing, simulating waste management as closely as possible. The constraints include those linking waste flows and mass balance, processing plants capacity, landfill capacity, transport vehicle capacity and number of trips. The linear programming model integrating different functional elements was solved by LINGO optimization software and various possible waste management options were considered during analysis. The model thus serves as decision support tool to evaluate various waste management alternatives and obtain the least-cost combination of technologies for handling, treatment and disposal of solid waste.

Investigation on the Effect of Asymmetric Cyclic Loading on Ratcheting Deformation and Bulk Texture Development in HSLA Steel

Pushpendra Kumar Dwivedi,R. Vinjamuri,S. K. Sahoo,Krishna Dutta 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

Ratcheting deformation in association with bulk texture evolution in HSLA steel is studied in this investigation. The cyclicdeformation behaviors and damage modes of the specimens are obtained at room temperature, employing asymmetric stresscontrolledtests under various combinations of mean stress and stress amplitudes. Bulk texture measurements of the specimensare done adopting an X-ray diffraction analysis. The results exhibit an increase in strain accumulation from 0.23 to 30.61%associated with a sharp reduction in ratcheting life from 3320 to 880 cycles by the increment in mean stress/stress amplitude. A continuous cyclic softening until the final failure is observed for all the ratcheting tests. It is noticed that variation of meanstress is more detrimental than stress amplitude in controlling strain accumulation while the effect of stress amplitude is morepronounced than mean stress for the reduction of ratcheting life. The fracture surface morphology indicates typical striationformation in the crack propagation region along with overload failure. The bulk texture studies indicate that there is a transitionbetween ‘ϒ’ fiber and ‘ζ’ fiber during all loading conditions. The texture intensity is increased from 5.71 to 11.68 withprogressive ratcheting strain accumulation. Here also, influence of stress amplitude is more significant than the mean stress.