Indian Institute Of Technology Bombay Research Articles

Centrifuge modeling of levees with geocomposite chimney drain subjected to flooding

The objective of present study is to evaluate the performance of a levee subjected to flooding and seepage through centrifuge model tests. For this, six model tests were conducted on a 240 mm high levee model at 30g in a 4.5 m radius large beam centrifuge. A custom-developed simulator is employed to induce identical flood rates on the upstream side of models. Further, using (a) geocomposite (GC) and (b) sand-sandwiched geocomposite (SSGC) as internal chimney drain, the suitability of GC material for dissipation of pore-water pressure (PWP) is also studied. The results of the centrifuge tests are discussed in terms of the development of upstream flood function, PWP within the levee body, and the surface settlements at the levee's crest. Further, the influence of an internal chimney drain, the material used for its construction, and its type and composition on the seepage response of the levee are discussed. It is observed that a GC-based chimney drain with sand cushioning on both sides in the horizontal portion of the chimney drain performs well. Further, digital image analysis of SEM micrographs of exhumed GC after centrifuge tests and the analyzed PWP data during sustained flooding-induced seepage is found to corroborate well.

Talicabtagene Autoleucel: First Approval.

Talicabtagene autoleucel (NexCAR19™) is a chimeric antigen receptor (CAR) T-cell therapy being developed by the Indian Institute of Technology, Bombay (IIT-B) and Immunoadoptive Cell Therapy (ImmunoACT) for the treatment of relapsed/refractory B-cell malignancies. Talicabtagene autoleucel contains autologous T cells from the patient, which have been modified to express a humanized anti-CD19 CAR that targets B cells. A single intravenous dose of talicabtagene autoleucel was associated with high response rates in pooled results from a phase I and phase II trial in patients with relapsed/refractory B-cell malignancies. Talicabtagene autoleucel was approved in India for the treatment of relapsed/refractory B-cell lymphomas and relapsed/refractory B-cell acute lymphoblastic leukaemia on 13 October 2023. This article summarizes the milestones in the development of talicabtagene autoleucel leading to this first approval for relapsed/refractory B-cell lymphomas and relapsed/refractory B-cell acute lymphoblastic leukaemia.

Aerosol sources characterization and apportionment from low-cost particle sensors in an urban environment

Low-cost sensors (LCS) have the potential to provide accurate and reliable measurements of air quality in real-time. This improves our ability to monitor, identify sources of pollution and develop mitigation strategies for effective air quality management. However, recent research on LCS has primarily focused on monitoring, exposure assessment, and calibration. In this study, we investigate the applicability of LCS data collected at ambient sites for characterizing and apportioning aerosol sources. Non-negative matrix factorization (NMF) was applied to the size-resolved data collected across five sites within the Indian Institute of Technology Bombay (IITB) campus in Mumbai using the LCS Alphasense OPC-N2. The sampling was done for 15 days at 5 locations in IITB, and each site only had 3 days of data. NMF resolved two factors for three sites, namely aromas (S2), hostel hub (S3) and central library (S4), while three factors were resolved for two sites, namely construction site (S1) and main gate (S5). Two common sources were determined for all the sites: (i) dust and marine source and (ii) traffic and combustion sources, which agree with the sources identified by studies in the literature. The third factor resolved at sites S1 and S5 is representative of heavy-duty diesel vehicles (HDDVs), which is present for a very short period and is captured because of the capability of high temporal resolution of the LCS. This offers a unique, cost-effective advantage of LCS for capturing episodic activities. The study suggests that in low- and middle-income countries with limited air quality monitoring capabilities, the size-time-resolved PM concentration data obtained from a network of low-cost sensors can estimate the pollution sources. This study provided evidence that despite their inherent limitations, LCS can be useful in attaining interpretable information about pollution sources and recommends extensive use of LCS for source characterization in the future.

Studies on the performance of water retention type tailings dams subjected to filling and inertial loading in a geotechnical centrifuge

The past decade has witnessed the failure of numerous tailing storage facilities and earthen dams. The most common factors causing failure include seepage and slope instability, apart from seismic activities. In the present study, a series of centrifuge model tests have been conducted to study the performance of water retention type (WRT) tailings dams impounded with fine tailings material (and water) on the upstream side. A custom-designed test setup to simulate upstream reservoir filling and inertial loading is employed in a 4.5 m radius large beam geotechnical centrifuge facility available at the Indian Institute of Technology Bombay, India. The centrifuge models were instrumented with pore pressure and displacement transducers to record porewater pressure (PWP) and surface settlement, respectively, and to ensure long-term safety and integrity of tailings dam. Additionally, an onboard digital camera was used to capture the front elevations of the centrifuge models to perform digital image analysis (DIA) for deducing slope face movements, surface settlements, and failure patterns. The results effectively demonstrate the performance of the WRT dam, delineate the slip surface and failure pattern, and quantify the critical design parameter related to inertial loading, which is the horizontal seismic coefficient (i.e. KHyield and KHmax). Based on these physically observed results, the analytical equations were also deduced for the WRT dams to quantify the stability (in terms of factor of safety, FS) and deformation response. The analytically obtained results agree reasonably well with the performance of WRT tailings dam models in the geotechnical centrifuge.

First person – Neha Saxena

ABSTRACT First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping researchers promote themselves alongside their papers. Neha Saxena is first author on ‘ Stiffness-dependent MSC homing and differentiation into CAFs – implications for breast cancer invasion’, published in JCS. Neha conducted the research described in this article while a PhD student in Professor Shamik Sen's lab at the Indian Institute of Technology Bombay, Mumbai, India. She is now a postdoctoral fellow in the lab of Professor Siddharth Dey, based in the Bioengineering Building, University of California, Santa Barbara, USA, investigating the role of the microenvironment in disease and the progression of embryonic development.

Tracking the Impact and Trends in Water Resources Research in India: A Scientometric Analysis

This study intends to analyse the research trends, growth, and collaboration patterns in the field of Water Resources in India. The source for the data collection is the Web of Science (WoS) Core Collection Database. A total of 797 publications published during the period from 2016 to 2021 satisfying these search criteria were pulled out to perform further analysis. This study revealed that Water Resources Management is the most productive journal with 26 articles (3.26%), followed by Arabian Journal of Geosciences 22 (2.76%), Environmental Earth Sciences 21 (2.63%) publications got 2nd and 3rd rank respectively. the year 2020 highest number of articles 236 (29%) were published on water resources followed by the year 2019 with 149 (18.69%).The Most productive author Malik, Anurag from Punjab Agricultural University is in the top position with 16 (2.007%) published articles. 177 (22.2%) of the total publication have two authored contributions taking the first position. Indian Institute of Technology Bombay published the highest number of articles i.e., 48 (6.02%) occupy 1st rank. Department of Science & Technology India funded 6.27%of published articles in the field of Water Resources Research.USA has the highest number of collaborative research work with India. China comes second with AFI value of 8.50. The Internationalization Index of Indian Water Resources literature is 73.77.Co-operative efforts show that there are 580 scientific links created between other countries, depicting most publications collaborated with authors from more than two countries.

Quantification of COVID-19 Vaccine Coercion in India: A Survey Study.

Informed consent is the cornerstone of medical ethics, enshrined in the constitution of most countries, as well as in international documents. However, mandates for coronavirus disease 2019 (COVID-19) vaccination as well as coercion were prevalent in many places in the world, including in India. Against this background, we did a cross-sectional study to assess and quantify the extent of COVID-19 vaccine coercion in India. A cross-sectional study was conducted after obtaining ethical clearance from the Indian Institute of TechnologyBombay (IITB). This survey was conducted using a pretested questionnaire anonymously amongst college students and adults in Mumbai from October 2022 to December 2022. The questionnaire contained details of why the vaccine was taken, and if the participant was a student. Descriptive analysis was conducted and frequencies, percentages along with 95% confidence intervals were used to summarize the findings. A total of 483 participants responded, which included both students and non-students, of which 470 participants reported having taken the vaccine. A total of 106 (21.95%, 95% CI 18.48%-25.85%) reported to have been pressured into taking the vaccine. The level of coercion was similar among college students (78, 21.61%, 95% CI 17.67%-26.14%) and non-student adults (28, 22.95%, 95% CI 15.82%-31.43%). Conclusion: A significant proportion was coerced into taking the vaccines, violating the requirement for informed consent. These results are of paramount importance for future policies as well as for posterity.

Postures anomaly tracking and prediction learning model over crowd data analytics.

Innovative technology and improvements in intelligent machinery, transportation facilities, emergency systems, and educational services define the modern era. It is difficult to comprehend the scenario, do crowd analysis, and observe persons. For e-learning-based multiobject tracking and predication framework for crowd data via multilayer perceptron, this article recommends an organized method that takes e-learning crowd-based type data as input, based on usual and abnormal actions and activities. After that, super pixel and fuzzy c mean, for features extraction, we used fused dense optical flow and gradient patches, and for multiobject tracking, we applied a compressive tracking algorithm and Taylor series predictive tracking approach. The next step is to find the mean, variance, speed, and frame occupancy utilized for trajectory extraction. To reduce data complexity and optimization, we applied T-distributed stochastic neighbor embedding (t-SNE). For predicting normal and abnormal action in e-learning-based crowd data, we used multilayer perceptron (MLP) to classify numerous classes. We used the three-crowd activity University of California San Diego, Department of Pediatrics (USCD-Ped), Shanghai tech, and Indian Institute of Technology Bombay (IITB) corridor datasets for experimental estimation based on human and nonhuman-based videos. We achieve a mean accuracy of 87.00%, USCD-Ped, Shanghai tech for 85.75%, and IITB corridor of 88.00% datasets.

Design and development of an in-flight simulator for flooding and drawdown

Geotechnical structures such as levees, dykes, canals and tailing dams, when subjected to extreme climatic conditions such as flooding and drawdown, are prone to failure on the upstream and downstream sides due to transient seepage conditions. Therefore, it is imperative to physically replicate such conditions in the actual stress state. Hence, the objective of this paper is to present the performance of an in-flight simulator developed to simulate flooding and drawdown (ISFD) events at enhanced gravities. The working principle, design details, various components of the developed simulator and calibration at normal (1g) and high gravities are discussed. In this study, the calibration and performance of the ISFD set-up were demonstrated on a model levee section in a 4.5 m radius large beam geotechnical centrifuge facility at the Indian Institute of Technology Bombay, India. In total, three centrifuge model tests were conducted on a scaled-down levee section (with and without internal drainage layers) constructed with silty sand-type material to validate the ISFD capabilities. In addition, seepage and slope stability analysis for the centrifuge models was carried out using Plaxis-2D geotechnical software, which compared favourably with physically observed tests results.

Centrifuge model studies on the performance of earthen dams with geocomposite internal drain subjected to pseudostatic seismic loading

This paper evaluates geocomposite (GC) as an internal drain for seepage control in earthen dams subjected to upstream impoundment and inertial loading through centrifuge model tests. A total of five centrifuge tests were performed on a homogeneously built small earthen dam section having prototype height of 7.2 m with 1H:1V side slopes at 30 g-level using a 4.5 m radius large beam geotechnical centrifuge available at the Indian Institute of Technology Bombay, India. The studied earthen dam models had an internal drain in the form of (a) a geocomposite horizontal drain (GC HD); (b) a sand-sandwiched geocomposite horizontal drain (SSGC HD); (c) a geocomposite chimney drain (GC CD); and (d) a sand-sandwiched geocomposite chimney drain (SSGC CD). The seepage-deformation response of the GC equipped earthen dam models is presented in terms of the development of pore-water pressure (PWP), phreatic surfaces, surface settlements (sc), and downstream slope face movements (sf). The behavior of the earthen dam model without any internal drain is also presented for comparison. In the case of an earthen dam with GC internal drain both as HD and CD, it was found to be efficient up to some extent in restricting phreatic surfaces, but phreatic surfaces were observed to be close to downstream side slope. However, a sand-sandwiched GC internal drain HD and CD seemed more promising in restricting the phreatic surface much within the downstream region and imparting higher stability even during sustained inertial loading conditions. The study concludes that SSGC chimney drain can be safely adopted for seepage control in small earthen dams and similar geotechnical structures viz levees, raw water reservoirs (RWRs), coastal protection structures, etc.

Sweet Synthesis

Sweet Synthesis

Systems and Control Engineering at IIT Bombay [Institutes in Control

The city of Mumbai charms every visitor. In particular, its warmth and ethos have remained unchanged over the years. The crowds in the suburban trains and the average person on the street continue to exude this warmth, cutting across social boundaries. Tucked away in the northeast corner of this sprawling metropolis is a still sylvan paradise, where birds chirp, cows moo, monkeys chatter, and the leopard pays periodic visits. And this sylvan paradise hosts an institute of global repute: the Indian Institute of Technology (IIT) Bombay. In this institute is a group, unique in many ways, with faculty members from across the spectrum of science and engineeringÑelectrical, chemical, mechanical, and aerospace engineering as well as applied mathematicsÑwho have established a much-envied academic entity to be reckoned with: Systems and Control. In this issue of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">IEEE Control Systems</i> , we speak with Debasish Chatterjee (Convener, Systems and Control, IIT Bombay) and a few others in their group.

100 years of the Devine Teacher - Student relationship among the three Generations of Indian Geoscientists (1920s – 2020s): A remarkable Story of Knowledge transfer from T. N. Muthuswami Iyer “TNM” through A. Parthasarathy to G. Shanmugam and beyond

The divine teacher-student relationship that covers 100 years of knowledge transfer is the underpinning of this remarkable personal story. Importantly, this narrative is about an Indian genius and a geologic pioneer, Professor T. N. Muthuswami Iyer, known as TNM. The first generation (1920s-1960s) TNM began his teaching career as a crystallographer and a mineralogist at the University of Madras-Gundy Campus (Chennai) in 1924, and continued at the Presidency College (Madras), Sager University (Madhya Pradesh), and Annamalai University (Tamil Nadu). One of his early students at Presidency was A. Parthasarathy, who later studied at the Imperial College in London (UK) and earned his Ph.D. in Engineering Geology from the London University (UL) in 1954. The second generation (1940s-1980s) Prof. Parthasarathy became the Head of Applied Geology section in the Civil Engineering Department at the Indian Institute of Technology (IIT) Bombay in 1964. The third generation (1960s-2020s) G. Shanmugam earned his B.Sc. in Geology and Chemistry from Annamalai University with a First Class (1965) and started teaching science in a local high school in his hometown of Sirkazhi, Tamil Nadu. TNM, who was the Head of Geology at Annamalai University in 1965, motivated G. Shanmugam to quit his teaching job and pursue M.Sc. in Applied Geology at IIT Bombay. Shanmugam earned his M.Sc. in Applied Geology at IIT Bombay under the guidance of Prof. Parthasarathy. Education and training at IIT Bombay propelled Shanmugam to receive his second M.S. and Ph.D. degrees in the USA. His Ph.D. research under the guidance of Prof. Kenneth R. Walker at University of Tennessee on Ordovician tectonics and sedimentation in the Southern Appalachians led to securing a research position with Mobil Oil Company in Dallas, Texas in 1978. Because of his global research on multiple domains while at Mobil and as post-retirement consultant since 2000 for oil companies in India and China, Shanmugam has to his credit 382 published works that include three Elsevier books on process sedimentology and petroleum geology, with the first two books were translated into Chinese language. He has authored 6 invited Encyclopedia Chapters for Elsevier and McGraw Hill Book Companies and has delivered 89 lectures worldwide during 1980-2021 period. He won the top "Special Prize" from Springer Journal of Palaeogeography in 2020 for "Excellent Papers" based on Science Citation Index (SCI) of five articles published during 2012-2018. Shanmugam's efforts in knowledge transfer during the COVID-19 global pandemic included giving virtual lectures on Zoom, Google Meet, and WebEx platforms to academia (e.g., Royal Holloway, University of London, IIT Bombay, and Ohio University). Shanmugam organized 23 onsite workshops on "Deep-water sandstone petroleum reservoirs" worldwide, which included (1) the UK Government Department of Trade and Industry (DTI), Edinburgh, UK, (2) Reliance Industries Ltd., Kakinada, India, (3) Hardy Oil, Chennai, India, (4) Oil and Natural Gas Corporation (ONGC), Mumbai and Kajuraho, India, (5) Petrobras, Rio de Janeiro, Brazil, (6) Research Institute of Petroleum Exploration and Development (RIPED) of PetroChina, Beijing, China, and (7) China University of Petroleum, Qingdao, China. The T. N. Muthuswami - A. Parthasarathy - G. Shanmugam lineage, spanning over 100 years, is unique and phenomenal in knowledge transfer among geoscientists. On the economic front, TNM and his lineages contributed directly to the petroleum, atomic mineral, cement, gemstone, and geothermal energy industries, among many others. The acronym "TNM" for T. N. Muthuswami Iyer is just perfect for a Transformational, Neoteric and a Motivating teacher and a noble soul!

Qualification of Fe0.95Co0.05Si2 as a reference material for high temperature measurement of the thermoelectric power factor

Precise characterization of thermoelectric (TE) materials is mandatory for a meaningful validation of scientific results, focusing on traceable determination of the Seebeck coefficient (S), the electric (σ) and thermal (κ) conductivity. These properties form the thermoelectric figure of merit zT = (S2σ/κ)T, which is used for assessment of TE conversion efficiency with respect to the absolute temperature T. The level of metrological standardization is characterized to date by available reference samples for the Seebeck coefficient, publications on best practice measurement approaches, and accomplished international round robin (RR) campaigns on transport property measurements.We report on the qualification of β-Fe0.95Co0.05Si2 (FeSi2) as the first semiconducting high temperature reference material for the TE power factor (PF = S2σ), which is currently developed by the German Aerospace Center (DLR) and the Physikalisch-Technische Bundesanstalt (PTB). The relation between the size of FeSi2 compacts obtained by current-assisted short time sintering and the resulting functional homogeneity of the material is presented, which is studied by spatially resolved Seebeck coefficient measurements at room temperature. Data from temperature dependent characterization of the PF is provided to assess functional stability and homogeneity under integral measurement conditions. The outcome of certification measurements at PTB report on individual uncertainty contributions as the base for a later testimony of FeSi2 as a metrological reference for the PF. Integral measurements have been expanded to further comparative test results obtained by the Korea Electrotechnology Research Institute (KERI), the Indian Institute of Technology Bombay (IITB), and the Netzsch Gerätebau GmbH. The findings give evidence of an excellent homogeneity, reproducibility and stability with low standard deviations for S and σ far below typical measurement uncertainties, which effectively demonstrates the suitability of FeSi2 as a future reference material for TE metrology at elevated temperatures up to 1000 K.

Opportunities beyond CO2 for climate mitigation

Opportunities beyond CO2 for climate mitigation

Assessing exposure to air pollution in India: approaches, data and gaps

Assessing exposure to air pollution in India: approaches, data and gaps Harish C. Phuleria Harish C. Phuleria Indian Institute of Technology Bombay, Mumbai, India Search for more papers by this author Abstract

First person – Ambuja Navalkar

ABSTRACT First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Ambuja Navalkar is first author on ‘ Oncogenic gain of function due to p53 amyloids occurs through aberrant alteration of cell cycle and proliferation’, published in JCS. Ambuja conducted the research described in this article while a postdoctoral fellow in Professor Samir K. Maji's lab at the Indian Institute of Technology Bombay, Mumbai, India. She is now a postdoctoral research associate in the lab of Professor Tanja Mittag at St. Jude Children's Research Hospital, Memphis, TN, USA, investigating the role of biomolecular condensation in transcription factor assembly and activity in the context of cancer.

The Decisive Role of Spin States and Spin Coupling in Dictating Selective O2 Adsorption in Chromium(II) Metal-Organic Frameworks.

Invited for the cover of this issue are Sourav Pal, Gopalan Rajaraman and co-workers at the Indian Institute of Technology Bombay, the Bhabha Atomic Research Centre and the Indian Institute of Science Education and Research. The image depicts how a mixture of atmospheric gases such as CO2 , H2 , N2 and O2 can be selectively separated using a Cr metal-organic framework where spin state and spin coupling play a crucial role. Read the full text of the article at 10.1002/chem.202104526.

Joint inversion of Rayleigh wave fundamental and higher order mode phase velocity dispersion curves using multi‐objective grey wolf optimization

AbstractRayleigh wave dispersion curves can be inverted to retrieve subsurface seismic velocity profiles. The inverse problem is ill‐posed, nonlinear and poorly conditioned, necessitating the application of global optimization methods. We present the application of the multi‐objective grey wolf optimization algorithm to perform joint inversion of the phase velocity dispersion curves corresponding to the fundamental and higher order modes of Rayleigh waves to obtain shear (S‐) and primary (P‐) wave velocity profiles. Multi‐objective grey wolf optimization is an extension of the grey wolf optimization algorithm for application to multi‐objective optimization and can be adapted to solve joint inversion problems. We compare the joint inversion results obtained from the multi‐objective grey wolf optimizer with those obtained from Markov chain Monte Carlo and fundamental mode inversion using the grey wolf optimizer on synthetic examples. The errors associated with phase velocity measurements are simulated by adding frequency‐dependent noise, with a higher level of noise added to the phase velocities corresponding to lower frequencies as compared to the higher frequencies. In the multimode joint inversion problem, the multi‐objective grey wolf optimizer gives a suite of solutions corresponding to each model parameter. The suite of S‐wave and P‐wave velocity profiles estimated from the multi‐objective grey wolf optimizer matches closely with the true model for the synthetic case studies even in the presence of noise. However, the suite of solutions has a greater spread for the last few layers, qualitatively indicating a higher degree of uncertainty in the predicted model parameter. The uncertainty in the solution for the deeper layers is a consequence of the uncertainty in the phase velocity at lower frequencies. We demonstrate the efficacy of the algorithm on recorded data from a shallow seismic survey conducted at the Indian Institute of Technology Bombay. The results from the multi‐objective grey wolf optimizer are in close agreement with those from Markov chain Monte Carlo, and the depth of investigation is found to be greater in comparison to results from refraction traveltime inversion.

Effects of pH and Time on Nickel Ion Release from Pediatric Stainless-Steel Crowns: An In-Vitro Comparative Study.

Background:Frequent use of stainless-steel crowns in pediatric dentistry has led to concerns that heavy metals in the crowns could be released into the mouth and potentially trigger allergic reactions. Of these constituents, nickel is known to be a common cause of hypersensitivity reactions.Aim:To evaluate and compare nickel ion release from pediatric stainless-steel crowns of 3M ESPE and DNTO Kids Crown at pH levels of 4.3, 5.5, and 6.3 for days 1, 7, 15, and 30.Methods:In this in-vitro study, nickel ion release (in PPM) from stainless steel crowns of 3M ESPE (n = 60) and DNTO Kids Crown (n = 60) in artificial saliva of pH 4.3, 5.5, and 6.3 on days 1, 7, 15, and 30 was analyzed using inductively coupled plasma-atomic emission spectrometry at Indian Institute of Technology-Bombay. Statistical analysis was performed using two-way and three-way analysis of variance (ANOVA) followed by least significant difference post hoc test and Spearman's rank order correlation. P < 0.05 was considered statistically significant.Results:In both groups (3M ESPE and DNTO Kids Crown), a significantly higher amount of nickel ion release was observed at pH 4.3. Among different time intervals, significantly maximum nickel ion release was observed on day 7. Nickel ion release from DNTO Kids Crowns was significantly higher than 3M ESPE at all the pH levels and time intervals.Conclusions:The pH of artificial saliva and nickel ion release is inversely related. The manufacturing process may affect the biodegradability of stainless-steel crowns. The maximum average nickel ion release from stainless steel crowns is below the recommended dietary intake but sufficient to cause allergic reactions.