Department Of Chemical Engineering

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

The Jews living in the state of Kerala enact their diasporic identities through a unique narrative network including songs, stories, and memoirs. Drawing on memory studies and affect theory, this article aims to examine selected Jewish folk songs as an example of entanglement of memory and culture, nostalgia and narrative. We study Oh, Lovely Parrot (2004), which is a compilation of 43 typical Kerala “parrot songs” – devotional hymns and songs for special occasions – translated from Malayalam into English by Scaria Zacharia and Barbara C. Johnson. Performances of these songs constitute cultural as well as affective phenomena that bring together Jewish identities, especially female rituals, in a collective effort to preserve their ethnic memory and its associated social identity. The music unique to this community illustrates the ancestry and tradition of the Kerala Jews which held them together even after ‘aliyah’ (a Hebrew word referring to the migration to the nation state of Israel post-1948). Using selected songs from the book, the article aims to examine the community's cultural identity markers related to experiential and discursive diasporic memory. It also draws on the memoir Ruby of Cochin: An Indian Jewish Woman Remembers (2001) by Ruby Daniel and Barbara C. Johnson to analyse the affective quality of songs which unites the community in collective imagination and in complex nostalgia narratives. © AesthetixMS 2020.

Department of Humanities and Social Sciences

Fulltext

Rupkatha Journal on Interdisciplinary Studies in Humanities

“An umbrella made of precious gems”: An examination of memory and diasporic identities in Kerala Jewish songs and literature

Hypothesis: Evaporating sessile drops containing surface active colloids is a promising route to self-assemble two-dimensional nanostructures. The standard protocol is to first self-assemble surface active nanoscale particles at the water-vapour interface and subsequently transfer it on to a solid surface. Colloidal monolayers with very few morphologies have been fabricated, exploiting this bottom-up self-assembly technique. However, the evaporation kinetics under controlled humidity conditions may dramatically alter the microstructure of self-assembled colloidal monolayers at the liquid–vapor interface and that on the solid surfaces, an aspect that has not been fully addressed in the prior studies. Experiments: To this end, we present an experimental study of evaporation driven self-assembly of soft poly(N-isopropylacrylamide) (pNIPAM) microgel particles loaded in a sessile drop. The surface-active microgel particles spontaneously populate the water-vapour interface facilitating the suppression of the coffee-ring effect and the formation of monolayer stains. The role of evaporation kinetics under controlled humidity conditions on the colloid's microstructure adsorbed to the solvent-air interface and on the morphology of the colloidal monolayer transferred onto the solid surface are studied in detail. Findings: The formation of particle-free and particle-rich regions at the water–vapor interface is observed for sessile drops evaporated under saturated humidity conditions. We show that the evaporation induced shrinkage of the interface area and the enhancement of the areal density of microgel particles adsorbed onto the interface leads to a restructuring of the particle-laden interface. The rearrangement of microgel particles along the water–vapor interface resembling the de-wetting assisted patterns is transferred to the solid substrate upon complete evaporation of the solvent. The microgel particles in the deposit assemble into domains with enhanced crystalline order. The evolution of Voronoi entropy across the monolayer deposit patterns obtained by the standard and slow evaporation routes are presented. © 2020 Elsevier Inc.

World University root node

Department Of Physics

Journal of Colloid and Interface Science

Colloidal monolayers with cell-like tessellations via interface assisted evaporative assembly

The stable operation of a turbulent combustor is not completely silent; instead, there is a background of small amplitude aperiodic acoustic fluctuations known as combustion noise. Pressure fluctuations during this state of combustion noise are multifractal due to the presence of multiple temporal scales that contribute to its dynamics. However, existing models are unable to capture the multifractality in the pressure fluctuations. We conjecture an underlying fractional dynamics for the thermoacoustic system and obtain a fractional-order model for pressure fluctuations. The data from this model has remarkable visual similarity to the experimental data and also has a wide multifractal spectrum during the state of combustion noise. Quantitative similarity with the experimental data in terms of the Hurst exponent and the multifractal spectrum is observed during the state of combustion noise. This model is also able to produce pressure fluctuations that are qualitatively similar to the experimental data acquired during intermittency and thermoacoustic instability. Furthermore, we argue that the fractional dynamics vanish as we approach the state of thermoacoustic instability. © 2021 Author(s).

Department of Aerospace Engineering

Chaos

Capturing multifractality of pressure fluctuations in thermoacoustic systems using fractional-order derivatives

The exhaustion of oil reserves encourages enhanced oil recovery (EOR) from mature oil fields. Hence, several polymers, surfactants, and nanofluids are developed, improving the recovery of additional oil from such mature wells. However, increased cost, harsh reservoir environment, and lower stability presents a significant challenge in developing a multicharacteristic injecting fluid, addressing all the past issues during oil recovery. Besides, almost all the earlier studies have demonstrated only higher viscosifying properties of polymers and rarely inspected the polymers' capabilities in altering surface wettability. In the present study, a guar galactomannan solution called viscosity-augmented guar (VAG) was prepared by the heat treatment of crude guar and removal of insoluble impurities. The resulting VAG solution demonstrated stable viscosity at higher temperatures (65 °C) under changing reservoir conditions. Additionally, the wettability alteration potential of VAG was evaluated by investigating the changes in the contact angle of oil-wet carbonate surfaces when treated with the VAG solution. Experimental results showed a reduction in the contact angle of the oil-wet surface to 81° after treatment with VAG from original surface values of 102° with the brine solution, indicating wetting transition from oil-wet to intermediate water-wet conditions. Moreover, the Fourier transform infrared spectroscopy and thermogravimetric analysis revealed the VAG's ability to displace oil components from the oil-wet surface. Additionally, emulsification studies showed a birefringence phenomenon of oil-water emulsions with VAG, reinforcing a proposed mechanism for wettability alteration by forming structured films oriented around the oil droplets in emulsions. The EOR potential of VAG showed an additional oil recovery of 7.31% of original oil in place compared to 3.59 and 2.98% by commercial polymers like xanthan gum (XGU) and partially hydrolyzed polyacrylamide, respectively. Overall, the favorable results of the VAG polymer are promising for promoting EOR, and for the first time, this study shows a polymer behavior in altering surface wettability of reservoir rocks and adds up different dimensions for future studies. ©

ACS Applied Polymer Materials

Wettability Alteration of the Oil-Wet Carbonate by Viscosity-Augmented Guar Galactomannan for Enhanced Oil Recovery

Although various efficient enhanced oil recovery (EOR) techniques have been proposed, the use of chemicals such as alkali, surfactants, and polymer in the field of EOR makes chemical EOR a promising method. The residual oil left behind after the secondary recovery process can be successfully displaced by decreasing the interfacial tension (IFT) between the liquid-liquid systems. Moreover, understanding the IFT between the liquid-liquid systems are essential in formulating and controlling the multiphase and multicomponent processes. As crude oil is a complex mixture of organic, inorganic compounds and heteroatoms, understanding the IFT of the pure hydrocarbon-water system is vital to develop robust models. In this study, the IFT between pure hydrocarbon-water systems in the presence of alkali has been explored. The IFT measurements were performed using a dynamic contact angle tensiometer using a Wilhelmy plate. Different hydrocarbon liquids such as hexane, heptane, decane and aromatics such as benzene and toluene were used. The monovalent NaOH and divalent alkali Ca(OH)2 in the concentration range of 0–37.5 mM are used to understand the effect of alkali on the IFT of the oil-water system. This paper also elaborates on the effect of temperature at 298.15 K, 323.15 K and 348.15 K on the IFT of hydrocarbon-water systems. The experimental results show that the increase in the concentration of alkali continuously decreased the IFT of hydrocarbon-water systems. Moreover, it has been found that the type of alkali also has a reasonable impact on the IFT of the hydrocarbon-water system. The divalent alkali [Ca(OH)2] is found to be more efficient in reducing the IFT of both alkane-water and aromatic-water systems than the moderately performed monovalent alkali (NaOH). The possible mechanism for the continuous reduction in IFT has been proposed using surface adsorption of hydroxide ions at the interface of the oil-water system. © 2020 Elsevier B.V.

Journal of Petroleum Science and Engineering

Effect of monovalent and divalent alkali [NaOH and Ca(OH)2] on the interfacial tension of pure hydrocarbon-water systems relevant for enhanced oil recovery

Thermodynamic hydrate inhibitors (THIs) are water-loving additives that in an aqueous phase preferentially interact with water and inhibit hydrate nucleation at given temperature and pressure conditions. Hydrate inhibition is one of the flow assurance challenges in oil and gas facilities, primarily for the production and transmission pipelines. In this era of a shift towards offshore production of oil and gas that is usually accompanied by large water cuts in production pipelines, the use of THIs requires a huge onboard inventory (of these additives); further, associated higher recovery costs and environmental issues has resulted in the identification and use of low dosage hydrate inhibitors (LDHIs). Thus, as the name suggests they are used in lower concentrations and do not present any space/storage problem on the offshore platforms. However, LDHI works differently, it primarily inhibits the growth and agglomeration of hydrate crystals thus ensuring flow assurance for a given period of time. Hence, an effective LDHI, may or may not delay hydrate nucleation, however, it should certainly reduce the kinetics of hydrate growth and should act as an anti-agglomerant. This work comparatively investigates the effect of three such additives on methane gas hydrate formation kinetics at very low concentrations. Sodium Dodecyl Sulphonate (SDS) is a well-studied molecule for gas hydrate formation kinetics, while SDS is a good anti-agglomerant (and has been used as anti-agglomerant in multiple gas hydrate studies), it is also a well-known hydrate promoter. In this work, additives having some similar molecular fragments to that of SDS were tested for better gas hydrate inhibition insights at molecular level. Sodium Benzene Sulphonate (SBS), Sodium Dodecyl Benzene Sulphonate (SDBS) and SDS was screened for methane gas hydrate formation experiments. A comparative kinetic study with these additives at two different concentrations (0.05 M and 0.1 M) has been presented for methane gas hydrate formation at 5 MPa (at the beginning of the experiments) and 274.15 K in n-heptane with 50% water cut, in a stirred tank isothermal reactor. The presence of a benzene ring in the molecular structure of the additive along with varying lipophilic tail and hydrophilic head on the methane gas hydrate formation kinetics are thoroughly investigated. © 2021 Elsevier B.V.

Journal of Molecular Liquids

A systematic molecular investigation on Sodium Dodecyl Benzene Sulphonate (SDBS) as a Low Dosage Hydrate Inhibitor (LDHI) and the role of Benzene Ring in the structure

In this work, microcrystalline cellulose (MCC) and sawdust (SD) green fillers have been demonstrated as reactive fillers and moisture reservoirs for enhanced curing and adhesion strength of one-component moisture-curing polyurethane (PU) adhesives. The chemical reaction between the MCC or SD fillers and isocyanates present in the PU adhesives was tracked using Fourier-transform infrared spectroscopy (FTIR), while the joint strength was determined using lap-shear tests. The results showed that the addition of MCC or SD leads to an accelerated curing rate through the early consumption of isocyanates. The lap-shear strength of unreinforced PU adhesive joints was achieved in 12 hours. In turn, the curing time in MCC and SD reinforced joints was achieved in 5 hours. The addition of MCC and SD fillers also enhanced the lap-shear strength of the joints under full cure conditions. An autocatalytic growth model was used to describe the lap-shear strength variation with respect to curing time. © 2021 Elsevier Ltd

Department of Mechanical Engineering

International Journal of Adhesion and Adhesives

Effect of cellulosic fillers addition on curing and adhesion strength of moisture-curing one-component polyurethane adhesives

The tool “Heatlines” is useful to understand heat flow and thermal management in enclosures experiencing convection. The heatline concept was first introduced by Bejan in the early 80’s. This article starts with the fundamental principles of heatlines or heat flow trajectories followed by a generalized governing equation for heatfunction (Π) applicable for fluid, nanofluid, or fluid-saturated porous medium experiencing steady natural or mixed convection within enclosures. An unified approach on derivation of heatfunction boundary conditions is presented based on Dirichlet conditions at junction of walls while Neumann conditions at walls for Π. The solution of Π also requires the selection of location of Π = 0 and this article outlines a generalized overview on the invariance of heatline trajectories irrespective of the location of Π = 0 for enclosures with or without adiabatic walls. Open loop or end to end heatlines demonstrate the heat flow path for conductive heat transport whereas open loop heatlines cross various regimes of dominant conduction or convection zones connecting the hot walls to the cold walls for convective heat transport. Closed loop heatline vortices (qualitatively similar to the flow vortices) depict the convective heat flow via the trajectories of the fluid flow vortices. A few feasible heatlines for conduction and convection dominant heat transport in enclosures (steady state) have been presented to illustrate the physics of “heatlines.” This article also addresses a few earlier works depicting discrepancies in heatline trajectories [discrepancies: heat flow to and from the same walls (isothermally hot/cold or adiabatic) or heat flow from the hot/cold to the adiabatic wall(s)] and proposes qualitative pictures for feasible heatlines for a few earlier case studies. Understanding the feasible implementation of heatlines is required as the inaccurate representation of heatlines may mislead future researchers in interpreting the energy flow. © 2021 Taylor & Francis Group, LLC.

Numerical Heat Transfer; Part A: Applications

Unified approach on numerical implementation of heatfunction boundary conditions for accurate prediction of heatlines involving steady convection in enclosures

Operator competence is critical to ensure safe and profitable operation in hazard intensive chemical process industries. Human errors account for the majority of the accidents in these industries. Therefore, it is imperative to develop methodologies to assess the competence of operators to minimize human errors. Traditional approaches to elicit operator competence are based on subjective measures and/or measures derived primarily from the process and operator actions. These approaches ignore the cognitive aspects of operators such as perception, decision-making strategy, and workload, which are crucial for improving performance. Recent development in sensor technology has enabled the researchers to measure human cognitive behavior objectively. Sensors such as eye-Tracking, electroencephalography (EEG) and galvanic skin resistance (GSR) are found to provide intrinsic human characteristics that cannot be measured otherwise. In this paper, we discuss how eye-Tracking can be used to capture control room operators' cognition and help infer their competence. Eye-Tracking provides information about the location of a person's gaze, which serves as a trace of their attention allocation. Eye gaze based metrics show a strong correlation with operator cognitive behavior such as situation awareness and cognitive workload during process monitoring tasks. © 2021 IEEE.

Department of Applied Mechanics

2021 International Conference on Maintenance and Intelligent Asset Management, ICMIAM 2021

Analysis of Control Room Operators' Competence using Cognitive Engineering Approaches to Improve Process Safety

Many countries are currently facing a severe water crisis. Further, in various industrial sectors, small and medium enterprises operate multistage, multiproduct batch processes that require large quantities of water. This work is motivated by the inability of such enterprises to deploy complex water-reuse strategies since their plants are neither well instrumented nor automated. The design and operational strategies of water reuse networks for multistage, multiproduct batch processes is inherently challenging due to the underlying discontinuities and other nonlinearities. In this paper, we propose an easy-to-implement water-reuse strategy that utilizes intermediate storage tanks with finite capacities. The strategy relies on a simple heuristic that maps discharge from specific stages to be stored in corresponding tanks. A fallback sequence is also provided in case the tank cannot accommodate the entire discharge volume. An analogous scheme for reusing water from the tanks in appropriate process stages is also proposed. In this paper, we demonstrate using a textile industry case study that this simple reuse strategy can result in significant water savings. For this, we develop an optimal production schedule using a genetic algorithm that simultaneously minimizes production makespan and the freshwater consumption. Our results show that for a set of 4 products with up to 14 production stages, 76% of the freshwater could be reduced if 13 tanks can be deployed. Even with 2 tanks, the proposed strategy results a 42% reduction of the freshwater requirements. © 2021 Institution of Chemical Engineers