Department of Chemical Engineering

Indian Institute of Technology Hyderabad (IITH) is a premier institute of science and technology established in 2008. IITH has been consistently ranked in the&nbsp;<a href="https://iith.ac.in/reports/" rel="noopener noreferrer">top 10 institutes</a>&nbsp;in India for Engineering&nbsp;<a href="https://www.nirfindia.org/2021/EngineeringRanking.html" rel="noopener noreferrer" target="_blank">according to NIRF</a>&nbsp;making it one of the most coveted schools for science and technology in the country.

IITH offers&nbsp;<a href="https://iith.ac.in/academics/under-graduate/">undergraduate programs</a>&nbsp;in all the classical engineering disciplines, applied sciences, design, as well as several modern interdisciplinary areas. Students are given a flexibility to explore a broad set of areas, and potentially pursue a minor or double major in a discipline that is not their own. Students who wish to seek a deeper understanding of their own discipline are strongly encouraged to get involved in cutting-edge research with the help of a faculty to mentor them, and earn an Honors in their own field.

The very foundation of IIT Hyderabad is based on&nbsp;<a href="https://iith.ac.in/research/">research and innovation</a>. The vibrant research culture is evident from the number of patents and publications that IITH produces consistently every year. IITH offers&nbsp;<a href="https://iith.ac.in/academics/programmes-offered/">graduate programs</a>&nbsp;at both a masters, and a doctoral level, in several diverse areas. There are separate programs for technology, design, science, and liberal arts. The&nbsp;<a href="https://iith.ac.in/academics/post-graduate/">MTech program</a>&nbsp;is offered in various modes and durations to cater to the ever-growing need of postgraduate level professionals in the country.

IITH encourages and supports&nbsp;<a href="https://iic-iith.netlify.app/index.html" rel="noopener noreferrer" target="_blank">innovation and entrepreneurship</a>&nbsp;at every stage. The minor program in entrepreneurship is open to all students of IITH, and many of the courses are offered by industrialists who are entrepreneurs themselves. There are various&nbsp;<a href="https://iith.ac.in/research/centres-incubators/">innovation centers and incubators</a>&nbsp;that promote entrepreneurship and help mentor young innovators. IITH has been very successful in building tie-ups with leading academic institutions around the globe.

IITH enjoys a very special relationship with Japanese universities and industries that goes beyond academic and research collaborations. In fact, some of the iconic buildings in IITH campus will carry the signature of Japanese architecture.

IITH creates a unique holistic ecosystem for education that offers interactive learning, a very flexible academic structure, cutting-edge research, strong industry collaboration, and entrepreneurship. This is an environment which enables students and faculty to translate their dreams into realities.

IIT Hyderabad

We investigate the dynamics of two immiscible fluids in a cross-junction via three-dimensional numerical simulations using the volume of fluid approach to track the dispersed phase's evolution. Different regimes, namely the dripping, squeezing, and jetting dynamics, have been observed for different dimensionless parameters, and we unveil a transition in regimes due to the concomitant interplay of capillarity, viscosity, and wettability. Our results reveal that hydrophobic channel surfaces favor a transition from squeezing to dripping behavior at a lower value of the capillary number. Moreover, higher viscosity ratios advance the process of squeezing, necking, and breakage on hydrophobic surfaces. A wettability-capillarity regime map is also presented that will have significant implications regarding the choice of substrate wettability, fluid properties, and flow rate in droplet dispensing devices. © 2021 Author(s).

World University root node

Physics of Fluids

Tuning of regimes during two-phase flow through a cross-junction

Sustainable production of hydrocarbon biofuels from biomass, fuels that are fully compatible with existing internal combustion engines, will allow the global transport economy to transition to a sustainable energy source without the need for capital-intensive new infrastructures. Hydrocarbon Biorefinery: Sustainable Processing of Biomass for Hydrocarbon Biofuels presents a comprehensive and easy to understand consolidation of existing knowledge for the production of hydrocarbon biofuels from biomass. Three major areas for the conversion of biomass to hydrocarbon biofuels are addressed: i) Chemical and thermochemical conversion processes, ii) Biological and biochemical conversion processes, and iii) Conversion processes of biomass-derived compounds. Additionally, the book includes process design, life cycle analysis of various processes, reaction engineering, catalysts, process conditions and process concepts, and is supported with detailed case studies. The economic viability of each process is specifically addressed to provide a clear guide for the economic development of future hydrocarbon biofuels. Hydrocarbon Biorefinery: Sustainable Processing of Biomass for Hydrocarbon Biofuels offers an all-in-one resource for researchers, graduate students, and industry professionals working in the area of bioenergy and will be of interest to energy engineers, chemical engineers, bioengineers, chemists, agricultural researchers, and mechanical engineers. Furthermore, this book provides structured foundational content on biorefineries for undergraduate and graduate students. © 2022 Elsevier Inc. All rights reserved.

Hydrocarbon Biorefinery: Sustainable Processing of Biomass for Hydrocarbon Biofuels

The use of electronic devices and wireless networks is increasing rapidly, and electromagnetic (EM) pollution remediation remains a challenge. We employed a unique approach to fabricate two ultrathin (approx. 53 μm) multilayered assemblies to address this. By sequentially stacking thin films of polyvinylidene difluoride (PVDF) and polycarbonate (PC) nanocomposites and interfacially locking them with a mutually miscible polymer (PMMA, polymethyl methacrylate), materials with enhanced structural properties and electromagnetic interference (EMI) shielding performance can be designed. Utilizing reduced graphene oxide (rGO) and molybdenum disulfide (MoS2) as a template, ferrite was grown on the surface to design two different nanohybrid structures (rGO-Fe3O4 and MoS2-Fe3O4). PVDF was composited with either rGO-Fe3O4 or MoS2-Fe3O4, and multiwall carbon nanotubes (CNTs) were dispersed in the PC component. As PC and PVDF are immiscible, their poor interface would result in inferior structural properties, which can be challenging in designing EMI shielding materials due to cyclic thermal fatigue. Hence, PMMA is sandwiched to interfacially stitch the components (PC and PVDF) and improve interfacial adhesion. This was confirmed using SEM/EDS and Raman mapping/imaging. The mechanical stability of the multilayered assemblies was characterized using a dynamic mechanical analyzer (DMA), and the storage modulus was found to be as high as 2767 MPa at 40 °C (@constant frequency and strain amplitude), for the multilayered film with rGO-Fe3O4 in PVDF, PMMA as a sandwich layer and CNTs in PC. A typical assembly of 9 multilayers (∼480 μm) with rGO-Fe3O4 in PVDF, and CNTs in PC, and interfacially stitched with PMMA gave rise to a high EMI shield effectiveness (SET) of -26.3 dB @ 26.5 GHz. This unique arrangement of a multilayered assembly suppressed EMI primarily by absorption. © 2021 The Royal Society of Chemistry.

Fulltext

Nanoscale Advances

Ultrathin structures derived from interfacially modified polymeric nanocomposites to curb electromagnetic pollution

The linear stability analysis of a viscoelastic (Oldroyd-B) liquid layer subjected to an oblique temperature gradient (OTG) is investigated numerically. For the case of low liquid elasticity, the analysis shows a strong stabilizing effect of the horizontal component (HTG) of the OTG on the two elastic modes emerging due to the presence of the vertical component (VTG) of the OTG. However, if the liquid elasticity is sufficiently large, the HTG fails to stabilize the upstream elastic mode. The liquid elasticity stabilizes the Newtonian interaction mode arising out of the interaction between the HTG and the VTG. The thermocapillary flow introduced by the HTG leads to the development of a new elastic mode absent in the case of a Newtonian liquid layer. The present paper thus shows that the elasticity of the liquid plays a major role in the competition between various instability modes to determine the dominant mode of instability. © 2021 Author(s).

Thermocapillary instability in a viscoelastic liquid layer under an imposed oblique temperature gradient

The hydrodeoxygenation (HDO) of guaiacol was investigated in a batch reactor using Ni-Co/γ-Al2O3 catalysts prepared by co-impregnation method. The structural and physicochemical properties of the catalysts were investigated using BET, XRD, H2-TPR, FT-IR, and NH3-TPD. The characterization results revealed that the formation of various Ni-Co composite species strongly depend on the Ni/Co mole ratio, total metal loadings, and the calcination/reduction temperature. The 6.1Ni3.05CoAl (Ni/Co = 1:2) catalyst seeds the formation of NiCo2O4 spinel structure and subsequent formation of Ni-Co alloy, which represents as specific active site for direct demethoxylation/deoxygenation reaction. The synergistic interaction of Ni-Co enhances the selectivity of benzene. The benzene selectivity of 35.2 % and cyclohexane selectivity of 59.1 % with complete conversion of guaiacol (98.9 %) were achieved with the 3.05Ni6.1CoAl catalyst at 575 K. A tentative reaction pathway is proposed based on the product distribution accomplished during HDO reaction. The structural property was correlated with activity to explore the mechanistic insights. © 2020 Elsevier B.V.

Molecular Catalysis

Synergistic effect of Ni-Co alloying on hydrodeoxygenation of guaiacol over Ni-Co/Al2O3 catalysts

Rapid detection of small amounts of Staphylococcus aureus (S. aureus) in whole blood and the corresponding diagnosis of S. aureus is a complicated and time-consuming process. Gold standard is to culture and grow bacteria before detection, which typically takes several days and requires skilled personnel. Here, we developed a microfluidic cartridge for the culture-free isolation of S. aureus in blood and diagnosed them using a multiplex polymerase chain reaction (PCR) method. Isolation of S. aureus was achieved from large volumes of blood (typically of the order of 5 ml) using Apolipoprotein H coated magnetic beads followed by ultrasonication, a similar kind of agitation utilized in an ultrasonic bath, to lyse the enriched bacteria. The designed cartridge consisted of a rotary valve to control the sample flow and, also to direct the samples to the designated chambers for the pre-processing and bacteria isolation. By comparing PCR results from batch process and cartridge based method, we proved that the current cartridge design was capable of S. aureus detection in whole blood sample. © 2021 IOP Publishing Ltd.

Journal of Micromechanics and Microengineering

Development of microfluidic cartridge for culture-free detection of Staphylococcus aureus in blood

Wet etching of Si{100} in an alkaline solution result in pyramidal structures, mostly bounded by four {111} planes. Such geometrical structures work as excellent light trapping structures and potentially help in the efficiency increment of solar cells. In this work, the effect of very low concentration potassium hydroxide (KOH) on the etched surface morphology of Si{100} is systematically studied. KOH concentration is varied from 1.0 to 0.1 wt% KOH in a step of 0.5 wt% to investigate the effect of etching concentration. Wet etching is carried at a fixed temperature of 70°C for 5 to 40 min of etching time. Samples are taken for investigation after every 5 minutes of interval. The lowest reflectance of around 12 % is measured on the samples textured in 0.5 wt% KOH for 10 min. © 2021 IEEE.

Department of Physics

2021 Symposium on Design, Test, Integration and Packaging of MEMS and MOEMS, DTIP 2021

A facile way of surface texturing of Si{100} using KOH for silicon solar cells

Bacterial cellulose (BC) produced through microbial fermentation has emerged as a viable precursor for carbon nanofibers (CNF) anode used in lithium-ion batteries. However, the low capacity and fading behavior of BC-derived CNFs render their usage in its pure form. Tuning the microstructure of CNFs in such cases plays an essential role in overcoming these negative ramifications and improves battery performance. In this study, the fermentation media used for BC production is modified by the addition of an iron catalyst, which can induce graphitization in the derived CNFs. Pure BC and catalyst-incorporated BC are pyrolyzed at 900 °C and 1800 °C to obtain CNFs, and the properties of derived CNFs are compared for understanding the role of incorporated catalyst. The structural, morphological, and electrochemical properties of CNFs are analyzed through X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, impedance spectroscopy, galvanostatic charge-discharge studies, and cyclic voltammogram studies. By possessing a higher graphitic content, catalyst-incorporated BC–derived CNFs exhibit an enhanced rate performance with a reversible capacity of 529 mAh g−1 after 100 continuous charge/discharge cycles at a current density of 0.2C. © 2021 Elsevier Ltd

Department of Materials Science and Metallurgical Engineering

Materials Today Chemistry

Catalytic graphitization of bacterial cellulose–derived carbon nanofibers for stable and enhanced anodic performance of lithium-ion batteries

In order to tackle the high compute cost of the multiphase simulations for dense medium cyclones, the development of an open source high fidelity LES based algebraic slip mixture multiphase flow solver is presented. The solver is parallelized on a general purpose GPU using a full load model, which provides around 13 times speed up as compared to a CPU implementation thereby, making design explorations using the current solver more feasible and less time consuming. The traditional ASM model was improved upon using more realistic slurry viscosity model and polydispersed hindered correlation for dense medium operation. The performance of the developed solver for dense medium cyclone operation was validated with the literature based gamma ray tomography (GRT) experimental results. The solver was then used to study the implication of variation in the key aspects of DMC operation such as pressure head, underflow diameter and feed particle concentration. The medium segregation is explained based on a novel non-dimensional force analysis of the drag, shear lift and turbulent dispersion. Finally, the response of the DMC in terms of hydrodynamic force analysis and density differential with the variation in design and operating variables has discussed. Based on the comprehensive force analysis of the medium a justification is provided as to why a lower pressure head is preferred for DMCs used in mineral processing. © 2021 Elsevier Ltd

Department of Mechanical and Aerospace Engineering

Minerals Engineering

Hydrodynamic force analysis of magnetite medium inside dense medium cyclone using multiphase GPU parallelized ASM model

3D microelectrodes are known to offer significant advantages compared with conventional thin-film electrodes due to their large surface area and shorter diffusion lengths. However, the direct use of 3D microelectrodes on bare stainless steel (SS) causes low rate capabilities, poor cycling performance, and safety concerns. Herein, these issues are addressed by designing 3D microelectrodes on the graphite-coated substrate with deposition of metal-organic framework (MOF)-derived nanostructured cobalt oxide petals at the base of the microelectrodes array. In this electrode configuration, graphite coating serves as an electrical interface between the microelectrodes and substrate, which lowers the resistance by providing efficient electron-conducting pathways. The cobalt oxide facilitates Li-ion diffusion and enhances the storage capability by conversion redox reactions. As an anode material, this 3D composite electrode delivers outstanding performance with a discharge capacity of 913 mAh g−1 at 100 mA g−1 current density even after 200 cycles. Furthermore, a diffusion-limited model using the finite element method is developed to investigate the time-dependent Li-ion transport across 3D microelectrodes. The computational study demonstrates the advantages of 3D carbon microelectrode morphology over the conventional planar electrodes. The excellent cyclic stability with outstanding specific capacities confirms the potential applicability of this novel electrode for high-performance lithium-ion batteries. © 2021 The Authors. Advanced Energy and Sustainability Research published by Wiley-VCH GmbH.