Department of Applied Mechanics

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

In this work, an attempt has been made to discriminate arousal and valence dimensions in Electrodermal Activity (EDA) signals using Spiking Deep Belief Network (SDBN). EDA signals having different arousal and valence dimensions are obtained from public online database. These signals are divided into equal parts and normalized using channel normalization. Later, signals are subjected to SDBN for event-related features and classification. A leave-one-out cross validation is used to investigate the classification performance. The result shows that the SDBN classifiers are able to discriminate the emotional states. The network yields better classification performance for emotional dimensions of arousal and valence. It appears that the proposed approach can be used to differentiate autonomic and pathological conditions. © 2020 European Federation for Medical Informatics (EFMI) and IOS Press.

World University root node

Studies in Health Technology and Informatics

Emotion analysis using electrodermal signals and spiking deep belief network

In this study, an attempt has been made to distinguish between nonfatigue and fatigue conditions in surface Electromyography (sEMG) signal using the time frequency distribution obtained from analytic Bump Continuous Wavelet Transform. For the analysis, sEMG signals from biceps brachii muscle of 22 healthy subjects are acquired during isometric contraction protocol. The signals acquired is preprocessed and partitioned into ten equal segments followed by the decomposition of selected segments using analytic Bump wavelets. Further, Singular Value Decomposition is applied to the time frequency distribution matrix and the maximum singular value and entropy feature for each segment are obtained. The usefulness of both the features is estimated using the Wilcoxon sign rank test that gives higher significance with a p <.00001. It is observed that the proposed method is capable of analyzing the fatigue regions in sEMG signals. © 2020 IEEE.

Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS

Analysis of Isometric Muscle Contractions using Analytic Bump Continuous Wavelet Transform

SARS-CoV-2 has ushered a global pandemic with no effective drug being available at present. Although several FDA-approved drugs are currently under clinical trials for drug repositioning, there is an on-going global effort for new drug identification. In this paper, using multi-omics (interactome, proteome, transcriptome, and bibliome) data and subsequent integrated analysis, we present the biological events associated with SARS-CoV-2 infection and identify several candidate drugs against this viral disease. We found that: (i) Interactome-based infection pathways differ from the other three omics-based profiles. (ii) Viral process, mRNA splicing, cytokine and interferon signaling, and ubiquitin mediated proteolysis are important pathways in SARS-CoV-2 infection. (iii) SARS-CoV-2 infection also shares pathways with Influenza A, Epstein-Barr virus, HTLV-I, Measles, and Hepatitis virus. (iv) Further, bacterial, parasitic, and protozoan infection pathways such as Tuberculosis, Malaria, and Leishmaniasis are also shared by this virus. (v) A total of 50 candidate drugs, including the prophylaxis agents and pathway specific inhibitors are identified against COVID-19. (vi) Betamethasone, Estrogen, Simvastatin, Hydrocortisone, Tositumomab, Cyclosporin A etc. are among the important drugs. (vii) Ozone, Nitric oxide, plasma components, and photosensitizer drugs are also identified as possible therapeutic candidates. (viii) Curcumin, Retinoic acids, Vitamin D, Arsenic, Copper, and Zinc may be the candidate prophylaxis agents. Nearly 70% of our identified agents are previously suggested to have anti-COVID-19 effects or under clinical trials. Among our identified drugs, the ones that are not yet tested, need validation with caution while an appropriate drug combination from these candidate drugs along with a SARS-CoV-2 specific antiviral agent is needed for effective COVID-19 management. © 2020 Elsevier Ltd

Department Of Biotechnology

Department of Mechanical Engineering

Fulltext

Computers in Biology and Medicine

Multi-omics-based identification of SARS-CoV-2 infection biology and candidate drugs against COVID-19

The surface of a rectangular wing is morphed at high angles of attack such that it continues to operate at the reduced coefficient of lift (Cl) at which the baseline wing operates, but unlike the baseline wing, where the flow is separated, the flow remains attached on the morphed wing. A morphed surface is also generated to operate at a local design 2D (two-dimensional) Cl, which is obtained by incrementing the baseline Cl by a percentage at pre and post-stall angles of attack. The morphed surface is generated numerically using a novel ‘decambering’ technique, which accounts for the deviation of the coefficients of lift and pitching moment from that predicted by potential flow, analytically, using CFD and implemented experimentally by attaching an external Aluminium skin to the leading edge of the wing. Two different wing sections, NACA0012 and NACA4415, are tested on a rectangular planform. The effect of morphing on the aerodynamic performance is discussed, and aerodynamic characteristics are reported. Results indicate that significant improvement in aerodynamic performance is achieved at high angles of attack, especially at post-stall through this active morphed flow surface. © 2020 Elsevier Masson SAS

Aerospace Science and Technology

Three dimensional rectangular wing morphed to prevent stall and operate at design local two dimensional lift coefficient

The temperature of deep hydrothermal sedimentary reservoirs varies between 50 and 250 °C, while the temperature of injected CO2 can be much below the reservoir temperature. Most past studies did not consider temperature effect on the CO2 dissolution trapping in storage reservoirs. We have performed numerical simulations of coupled multiphase flow, solute, and heat transport for liquid/supercritical CO2 injection in a storage reservoir for different reservoir temperature, injection temperature, and reservoir permeability. During the injection of relatively cool CO2 in a warmer storage reservoir, brine density increases with CO2 concentration causing solutal fingering in the diffusive boundary layer and the creation of an isolated dissolved CO2 plume (gravity trunk) below the injection zone. We have found that in many cases, the formation of a gravity trunk creates a large convection roll beneath the injection point. For low and moderate reservoir temperatures (100 and 175 °C), solutal fingers are pulled towards the injection zone by the large gravity trunk convection roll. In contrast, for higher temperature reservoirs (&gt;206 °C), brine density decreases with dissolved CO2 concentration. Hence, for a reservoir temperature of 250 °C, solutal fingers do not develop, but reverse fingering from a dissolved CO2 mound is visible. We conclude that dissolution trapping achieves greater effectiveness for a reservoir temperature of 175 °C than those at 100 and 250 °C. We have also observed that free-phase CO2 below the caprock spreads faster for higher reservoir temperature and higher permeability, but it is not sensitive to injection temperature. ©2019. American Geophysical Union. All Rights Reserved.

Water Resources Research

Simulation of Gravitational Instability and Thermo-Solutal Convection During the Dissolution of CO 2 in Deep Storage Reservoirs

Helical coil tension springs made of shape memory alloy (SMA) materials generally undergo large deflection under loading during which their mean coil diameter changes noticeably. In the design of these helical coil springs, it is necessary to identify the real behaviour which may be affected by the variation in actual coil diameter. Therefore, a simple formulation is proposed in this paper for predicting instantaneous coil diameter. The predictions from present formulation match very closely with experimental measurements. The proposed formulation is relatively easy to adopt for design calculations. The effects of varying coil diameter on the spring characteristics are also discussed. This is very general and can be used for any helical spring which undergoes small or large deflections, although the proposed formulation is derived for SMA helical spring. Copyright © 2020 Inderscience Enterprises Ltd.

International Journal of Materials and Structural Integrity

A new simple formulation for instantaneous coil diameter of a SMA helical spring

The spreading of drops on surfaces is ubiquitous and has relevance to many technological applications. In this work, we present two-dimensional numerical simulations of the surface tension driven spreading of drops dispensed on a fluid-fluid interface. A comprehensive picture describing the equilibrium shapes of the drops is provided in the form of a state diagram. We show that the analysis of kinetics of drops that spread symmetrically on the fluid-fluid interface reveal several interesting features: (i) the existence of a single length scale that describes the spreading process, (ii) the power law dependence of the temporal variation of the geometrical parameters of the spreading drop, (iii) the linear dependence of the power law exponents on the equilibrium enclosing angle of the liquid drop, (iv) a strong dependence of the power law exponents on the spreading coefficient, and (v) a collapse of the spreading kinetics data into a master curve. Though restricted to two dimensions, our analysis provides a rationale for explaining experimentally determined power law exponents which have been reported to vary over a wide range and hence to understand the universal nature of the spreading process. © 2020 American Physical Society.

Department Of Chemical Engineering

Physical Review Fluids

Statics and dynamics of drops spreading on a liquid-liquid interface

The influence of surrounding gases, such as He, N2, atmospheric air, and Ar, and gas flow rate on the laser-induced breakdown spectroscopy (LIBS) characterization of coals in free space is studied. The atomic and molecular carbon (C2 and CN) emission intensities are observed to be higher in Ar and N2 ambiance. Quantitative analysis of carbon and ash content in different coal samples is carried out using the carbon bound atomic and molecular emission signals and the ash forming elements (Si, Fe, Mg, Al, Ca, Na, and K) signals. The sum of the LIBS emission of the all and major ash forming elements increased linearly with an increase in the ash content. Similarly, the ratio between the carbon signals (C I, CN, and C2) and the sum of major ash forming elements (Si, Al, Fe, and Ca) also showed a linear increase with the increase in carbon content in coal samples. The linear coefficient of regression, R2, was estimated to be 0.67, 0.58, and 0.85, and the root mean square of calibration samples was estimated to be 5.71, 5.82, and 5.57 wt% using the partial least square regression (PLSR) method for air (no flow), N2, and Ar atmosphere, respectively. The precision and accuracy of the carbon measurement in coal samples by the LIBS technique using the PLSR method were higher in the presence of Ar than air or N2 atmosphere due to the plasma shielding effect.

Department of Engineering Design

Effect of ambiance on the coal characterization using laser-induced breakdown spectroscopy (LIBS)

The origin, formation mechanism, and emission persistence time of atomic (C I) and molecular (CN Violet system and C2 Swan system) carbon emissions from coal plasma generated by laser ablation were studied using Time-resolved LIBS. © 2020 IEEE.

2020 Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2020 - Proceedings

Understanding the mechanism of molecular carbon emissions using time-resolved LIBS during online coal characterization

In this work, we studied the effect of common calcium channel blockers (Verapamil Hydrochloride and Nifedipine, usually prescribed for cardiovascular diseases) on the viscoelastic property of both tumorigenic (MCF-7) and vascular endothelial (HUVEC) cell-line. Specifically, an optical-tweezer was used to locally "press-down" on the cell membrane. Fluctuations of optically-trapped dielectric beads attached to the cell membrane were measured to study the effect of drugs on the mechanical properties of the membrane and the cytoskeleton. We observed that MCF-7 cells exhibit a significantly higher mean squared displacement (MSD) in response to these drugs as compared to HUVEC cells, under no-compression condition. Furthermore, optically induced compression of cell-membrane induced a significant drop in MSD of MCF-7 cells, whereas HUVEC cells showed a significant rise in MSD. To further test these results, we depolymerized actin-cytoskeleton using latrunculin-B and measured fluctuations of beads on the surface of cells. Immunofluorescence imaging of the actin cytoskeleton correlates with the variation in the viscoelastic response of MCF-7 and HUVEC under the influence of these drugs. Our power-spectrum analysis at 10 Hz shows that actin-depolymerization decreased the activity of both cell types; however, cells treated with nifedipine or verapamil showed contrasting effects. Together, these results show that clinically approved calcium-ion blocking cardiovascular drugs have a significant effect on the viscoelastic properties of circulating tumor cells in the blood. © 2020 ACM.