Sankha Banerjee | Massachusetts Institute of Technology (MIT) (original) (raw)

Papers by Sankha Banerjee

OMX presents a leverage router oriented towards intent-focused trading across a spectrum of marke... more OMX presents a leverage router oriented towards intent-focused trading across a spectrum of markets. It is a suite of 100 distinct tradable pairs that span cryptocurrencies, foreign exchange, interest rates, and equity markets. In contrast with existing decentralized derivatives exchanges, OMX offers enhanced leverage and an expansive selection of trading pairs, all underpinned by a competitive fee architecture. The architecture positions OMX as a cross-chain liquidity aggregator in the landscape of leverage for financial trading platforms.

IEEE Access, 2022

In this work, a novel compact and accurate glucose concentration measurement system is developed ... more In this work, a novel compact and accurate glucose concentration measurement system is developed using the well-established photoacoustic Near Infra-Red spectroscopy. The proposed in-vitro instrumentation methods are in a small form factor, making it a viable candidate and precursor for an in-vivo non-invasive wearable blood glucose monitoring in the near future. The accuracy comes from the phase sensitive detection of the electrical signal. This detection technique uses an off-the shelf modulator/demodulator integrated circuit configured as a lock-in amplifier to increase the signal to noise ratio multifold. No prior work on photoacoustic spectroscopy, has taken advantage of this detection methodology in such a small form factor. The dimension of the lock-in-amplifier is 13mm x 10.65mm x 2.65mm. The maximum linear dimension of the exciting laser is 5.6 mm. The acoustic sensor (transducer) has a dimension of 42mm x 12mm. Furthermore, the measurement and analyses of the observed data uses multiple stochastic and machine learning techniques to bring out the best correlation fit between the glucose concentration and a specific feature of the electrical signal. With these methods and techniques, a strong correlation was confirmed between the glucose concentration and the amplitude of the electrical signal. The computed correlation coefficient between the signal amplitude and glucose concentration is 97% while the p-value is 5.6E-6. To the best of our knowledge, this is the first work to report photoacoustic spectroscopy for glucose concentration measurement in a compact form, with lock-in amplifier and aided with machine learning algorithms for future application as a wearable device. INDEX TERMS Photoacoustic NIR spectroscopy, non-invasive glucose monitoring, lock-in-amplifier, machine learning.

physiological measurement to industrial monitoring systems. Sensors that can be easily integrated... more physiological measurement to industrial monitoring systems. Sensors that can be easily integrated with the host, while maintaining high sensitivity and reliability over a wide range of frequencies are not readily feasible and economical with homogenous piezoelectric materials. It is well known that two-phase piezoelectric-epoxy composites offer several benefits over their single phase counterparts, as the properties of the constituent phases combine to improve the range of applicability. However, the piezoelectric properties of these materials suffer from the electrically insulating properties of the epoxy matrix. The electrical properties of the matrix may be enhanced by including electrically conducting inclusions however, less is known about the mechanisms that drive the changes in these properties. Hence, this experimental investigation of sensor materials builds on the previous work in two-phase piezoelectric composites, where the aims are to understand the roles that specific fabrication parameters and inclusion composition play in determining the piezoelectric and iii dielectric performance the aforementioned composites. The materials under investigation will be comprised of Lead Zirconate Titanate, Epofix Cold-Setting Embedding Resin and multi-walled carbon nanotubes, i.e. the piezoelectric, epoxy and electrical inclusions respectively. Our work suggests that inclusion of MWCNTs enhances the piezoelectric and dielectric properties with increasing volume fraction below the percolation threshold. This work seeks to understand how the processing parameters: poling temperature, poling type and particle distribution influence the contact resistance, space charge double layer at the piezoelectric and conductor interfaces and electric field intensity at the piezoelectric boundary, which all ultimately dictate the piezoelectric and dielectric performance of the composite materials. Conventional solid oxide mixing, spin coating and deposition techniques will be used to fabricate the bulk and thick films. The piezoelectric and dielectric performance will be determined from the measurement of the piezoelectric strain coefficients, d33 and d31, dielectric constant, impedance and dielectric spectrum, dielectric loss tangent, and capacitance. These measurements will be correlated with inclusion size, shape, distribution, and surface morphology observations obtained from the scanning electron microscope (SEM) and transmission electron microscope (TEM).

Polymeric-ceramic smart nanocomposite piezoelectric and dielectric materials are of interest due ... more Polymeric-ceramic smart nanocomposite piezoelectric and dielectric materials are of interest due to their superior mechanical flexibility and ability to leverage characteristics of constituent materials. A great deal of work has centered on development of processes for manufacturing 0–3 continuity composite piezoelectric materials that vary in scale ranging from bulk, thick and thin film to nanostructured films. Less is known about how material scaling effects the effectiveness of polarization and electromechanical properties. This study elucidates how polarization parameters: contact versus corona, temperature and electrical voltage field influence the piezoelectric and dielectric properties of samples as a function of their shape factor, i.e., bulk versus thick film. Bulk and thick film samples were prepared via sol gel/cast-mold and sol gel/spin coat deposition, for fabrication of bulk and thick films, respectively. It was found that corona polarization was more effective for bot...

International shipbuilding progress, 2013

Accurate prediction of the highly-mixed flow in the near field of a surface ship is a challenging... more Accurate prediction of the highly-mixed flow in the near field of a surface ship is a challenging and active research topic in Computational Ship Hydrodynamics. The disparity in the time and length scales and the scales of entrainment dictates the use of bubble source and mixed-phase flow models in which the current state of the art models are ad hoc. This paper presents the air entrainment characteristics and multiphase turbulence modeling of the near-field flow of a canonical stern with the inclusion of simple geometry effects. Using state of the art Cartesian-grid numerical methods with the full field equations, high-resolution two-phase flow data sets of a canonical stern with three different half-beam to draft ratios are simulated down to the scales of bubble entrainment. These data sets are used as the foundation for: (1) characterization of wake structure and near-wake air entrainment of the stern; (2) analysis of turbulent mass flux in the wake of the stern; and (3) a priori...

Chapter 2. An analytical model for the prediction of the dielectric constant of three phase 0-3 p... more Chapter 2. An analytical model for the prediction of the dielectric constant of three phase 0-3 piezoelectric composites with electrically conductive inclusions ..

2019 IEEE International Electromagnetics and Antenna Conference (IEMANTENNA), 2019

With the growing technology wearable devices have become very popular now-a-days. The wearable de... more With the growing technology wearable devices have become very popular now-a-days. The wearable device is equipped with antenna is capable to transmit the entire sensor's data to the system for monitoring such as tracking, navigation, mobile computing, medical science and public safety. As a wearable antenna can be a part of the clothing, the design of antenna is very important to ensure comfort to the wearer without affecting the antenna performance. This paper intend to focus on the specification of the truncated square micro strip rectangular patch antenna by using jute as the substrate for the antenna and analysis that to design proper wearable antennas for Global positioning systems (GPS) applications at 1.575 GHz.

The FASEB Journal, 2008

The signaling events that link serum starvation to increased insulin action in myotubes have not ... more The signaling events that link serum starvation to increased insulin action in myotubes have not been defined. We hypothesized that serum starvation enhances phosphorylation of the AMP-activated protein kinase (AMPK) and other possible mediators of insulin sensitivity, ...

SN Applied Sciences, 2021

SCAPS simulation was utilized to complement previously published perovskite-on-Si tandem solar de... more SCAPS simulation was utilized to complement previously published perovskite-on-Si tandem solar devices and explore herein viable all-perovskite 4-T mechanically stacked and 2-T monolithic non-Pb tandem structures. CsSn0.5Ge0.5I3 (1.5 eV) was used as top cell wide bandgap absorber, while CsSnI3 (1.3 eV) was chosen as bottom cell low bandgap absorber. The top cell was simulated with AM 1.5G 1 Sun spectrum, and the bottom cell was simulated with the filtered spectrum from the top cell. To form a 2-T monolithic tandem device, ITO was used as the recombination layer; the current matching condition was investigated by varying the thickness of the absorber layers. For a current-matched device with a Jsc of 21.2 mA/cm2, optimized thicknesses of 450 nm and 815 nm were obtained for the top and bottom absorber layers, respectively. At these thicknesses, the PCEs of the top and bottom cells were 14.08% and 9.25%, respectively, and 18.32% for the final tandem configuration. A much simpler fabric...

A non-linear mathematical model is proposed to study the impacts of travelling in human-human tra... more A non-linear mathematical model is proposed to study the impacts of travelling in human-human transmission of COVID- 19.Two different regions are considered and transmission dynamics of COVID-19 dissemination in two regions caused by travelling from one region to other and infection during travel are discussed.Besides contacts between susceptible and infected population of a region off the travel,transmission of disease due to contacts during travel is also considered.The proposed model is analysed using stability theory of ordinary differential equation and feasibility of qualitative results ia checked through numerical simulations.From obtained results,it is shown that travelling and population dispersal can aggravate disease spreading in each region.It is also inferred that rate of travelling and rate of contacts during travel and off the travel can ease the disease to take endemic form and for high rates,it may become pandemic. Further numerical calculations are performed and cr...

Journal of Applied Physics, 2019

Plasma-wall interaction in the presence of secondary electron emission (SEE) can lead to a degrad... more Plasma-wall interaction in the presence of secondary electron emission (SEE) can lead to a degradation and reduction in the performance of plasma devices. Materials with complex surface architectures such as velvet, fuzz, and feathered surfaces have a lower SEE yield than the same materials with a flat surface and can, therefore, be useful for plasma applications. This reduction in the SEE is due to the trapping of secondary electrons in the microcavities formed by complex surfaces. In this paper, we present a rapid method for a simultaneous comparison of the SEE yield and surface properties of materials with different surface architectures. The method uses Scanning Electron Microscopy to simultaneously evaluate the surface morphologies and SEE yield properties for a microarchitectured surface. This technique was applied to carbon velvets, and results show agreement with recent theoretical models and with the direct determination of the SEE yield from measurements of the currents of...

Journal of Electronic Materials, 2019

Piezoelectric and electro-active composites are being investigated as a generation of self-powere... more Piezoelectric and electro-active composites are being investigated as a generation of self-powered energy harvesting devices for a wide range of applications. More specifically, three-phase piezoelectric composites are capable of maintaining high reliability, durability, and sensitivity, all while being economically feasible and nontoxic. In addition, three-phase composites can be tailored towards multifunctional applications depending on which material is incorporated as the third-phase. The criteria that governs the applicability of these composites depend upon their electromechanical properties such as their impedance, resistivity, conductivity, and dielectric constant. Therefore, the present work involves the fabrication of barium titanate-epoxy-zinc oxide (BT-Ep-ZnO) multifunctional composites, and the study of the variation of their electron transport properties. The volume fraction of BT was held constant at 0.40, while the volume fraction of ZnO was varied from 0.01 to 0.10. The dipoles of the electro-active phases were aligned using a contactless corona plasma discharge poling technique. The impedance, resistance, conductance, and capacitance were measured over a frequency range of 20 Hz to 10 MHz. The geometry of the composites was measured and used to normalize the data by calculating the resistivity, conductivity, and dielectric constant. The piezoelectric strain coefficients, d33 and d31, were measured using a piezometer at a frequency of 110 Hz. The fractured surface morphology and distribution of the particles were observed with a scanning electron microscope.

Conference Proceedings of the Society for Experimental Mechanics Series, 2019

Electro-active polymers and piezoelectric energy harvesting materials offer enormous potential fo... more Electro-active polymers and piezoelectric energy harvesting materials offer enormous potential for developing smart damping devices for the health monitoring of civil structures during unknown excitations (e.g., earthquakes, blasts, etc.). These auto-adaptive and intelligent composites convert mechanical energy to electric energy by generating an electric field when subjected to mechanical excitation. Variation in the strength of the electric field response can detect any change in the structural properties due to damage in the host structure. An experimental research plan is developed to investigate the effectiveness of these smart materials in structural engineering applications with the purpose of damage detection and mitigation. To this end, two phases of this research study are outlined as follows: (1) materials fabrication: the piezoelectric composites were fabricated using a solution based wet lab fabrication methodology. Bulk sample geometries (such as bulk cylinders) of the two phase (such as BaTiO3—Cement) composite electro-active materials were tested for their impedance and piezoelectric properties. The microstructure and elemental distribution of these materials were characterized using the Scanning Electron Microscope (SEM) and Energy-dispersive X-ray spectroscopy (EDS/EDX) to understand the process—structure—property relationships. The final composite product is labeled as electro-active smart aggregates in this project; (2) structural component testing: smart aggregates were embedded in a simply supported concrete beam to investigate their effectiveness in monitoring deflections of the beam under flexural testing. Electrical properties of smart aggregates will be presented herein.

Springer Series on Polymer and Composite Materials, 2017

Polymer composites have been extensively studied in the last few years toward application in sola... more Polymer composites have been extensively studied in the last few years toward application in solar-, thermoelectric-, and vibration-based energy harvesting technologies. Of late, polymer nanocomposites are being investigated successfully in hybrid organic–inorganic devices, in bulk heterojunction devices incorporating all flavors of solar cells, and through the perovskite structures. In the thermoelectric power generation arena, abundance of raw materials, lack of toxicity, and the feasibility for large-area applications are all advantages that polymer nanocomposites boast over their inorganic predecessors. Within the vibration-based energy systems, polymer nanocomposites are being used as the magnets within the harvester devices; they offer low rigidity and easy processing (spin coating, drop casting, and molding). Also, recent work has focused on utilizing polymer ceramic nanocomposites as electrostatic energy storage materials. Lastly, polymer-based piezoelectric materials can be used directly as an active material in different transduction applications.

Smart Materials and Structures, 2016

Three-phase lead zirconate titanate (PZT, PbZr0.52Ti0.48O3)-epoxy-multi-walled carbon nanotube (M... more Three-phase lead zirconate titanate (PZT, PbZr0.52Ti0.48O3)-epoxy-multi-walled carbon nanotube (MWCNT) bulk composites were prepared, where the volume fraction of PZT was held constant at 30%, while the volume fraction of the MWCNTs was varied from 1.0%–10%. The samples were poled using either a parallel plate contact or contactless (corona) poling technique. The piezoelectric strain coefficient (d33), dielectric constant (e), and dielectric loss tangent (tan δ) of the samples were measured at 110 Hz, and compared as a function of poling technique and volume fraction of MWCNTs. The highest values for dielectric constant and piezoelectric strain coefficients were 465.82 and 18.87 pC/N for MWCNT volume fractions of 10% and 6%, respectively. These values were obtained for samples that were poled using the corona contactless method. The impedance and dielectric spectra of the composites were recorded over a frequency range of 100 Hz–20 MHz. The impedance values observed for parallel-plate contact poled samples are higher than that of corona poled composites. The fractured surface morphology and distribution of the PZT particles and MWCNTs were observed with the aid of electron dispersion spectroscopy and a scanning electron microscope. The surface morphology of the MWCNTs was observed with the aid of a field emission transmission electron microscope.

Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, 2016

Three-phase piezoelectric bulk composites were fabricated using a mix and cast method. The compos... more Three-phase piezoelectric bulk composites were fabricated using a mix and cast method. The composites were comprised of lead zirconate titanate (PZT), aluminum (Al), and an epoxy matrix. The volume fraction of the PZT and Al was varied from 0.1 to 0.3 and 0.0 to 0.17, respectively. The influences of an electrically conductive filler (Al), polarization process (contact and Corona), and Al surface treatment, on piezoelectric and dielectric properties, were observed. The piezoelectric strain coefficient, d33, effective dielectric constant, εr, capacitance, C, and resistivity were measured and compared according to polarization process, the volume fraction of constituent phases, and Al surface treatment. The maximum values of d33 were ∼3.475 and ∼1.0 pC/N for corona and contact poled samples, respectively, for samples with volume fractions of 0.40 and 0.13 of PZT and Al (surface treated), respectively. Also, the maximum dielectric constant for the surface treated Al samples was ∼411 for...

Science of Advanced Materials

Three-phase, PZT(PbZr0.52Ti0.48O3)-Epoxy- Multi-walled Carbon-Nanotube (MWCNT) flexible films hav... more Three-phase, PZT(PbZr0.52Ti0.48O3)-Epoxy- Multi-walled Carbon-Nanotube (MWCNT) flexible films have been prepared via a combination solvent and spin coating technique. The composite materials were spin coated onto flexible stainless steel substrate, and either graphene or graphene - PMMA films were grown by a chemical vapor deposition process on the other side of the films. The thicknesses of the films were ~ 200 μm. The volume fraction of the MWCNTs was varied from 1% to 6%, while the PZT volume fraction was held constant at 30%. The strain coefficient and capacitance were measured as a function of the MWCNT volume fraction, and were subsequently used to determine the effective dielectric constant of the composite. Samples that incorporated graphene electrodes had higher effective dielectric constants than samples that incorporated graphene-PMMA electrodes and those with no top electrode. For example, the maximum values of effective dielectric constant for the composite films were ~...

MRS Proceedings, 2009

New materials, methods, and membranes are being developed for applications in water purification.... more New materials, methods, and membranes are being developed for applications in water purification. One of the model systems that can be used for fundamental studies in nanoscale transport phenomena for new membrane technologies are nanocapillary array membranes (NCAMs). Toward developing more efficient membranes for water desalination, parameters such as the concentration polarization region which are influenced by the unstirred layers, surface properties (e.g., surface charge and surface energy) of the nanocapillaries, and the electric double layer (EDL) which mediates transport across NCAMs must be better understood. In this paper, a series of parametric experiments that were conducted to better understand the relative importance of unstirred layers with respect to the transport across nanocapillaries are described. Bulk salt concentration and potential drop across the NCAMs, were varied in a systematic manner to determine the influence EDL thickness and electromigration on transpo...

Surface Science Reports, 2009

Phenomena in microsystems and nanosystems are influenced by the device walls due to the high surf... more Phenomena in microsystems and nanosystems are influenced by the device walls due to the high surfacearea-to-volume ratios that are a characteristic feature of these systems. The role of surfaces in these small-scale systems has led to natural interest in developing methods to manipulate surface-mediated phenomena toward improving device performance, developing next generation systems, and mitigating problems that arise due to interfacial interactions between surfaces and materials within microscale and nanoscale systems. This report presents a critical review of the existing literature as it relates to role of surfaces and surface modification in microsystems and nanosystems. In addition, this report strives to present this literature review with an eye on the tutorial aspect of surface modification for new researchers. Toward the dual goal of presenting a tutorial review with a critical analysis of literature many open scientific questions are discussed. Both chemical and physical surface modification methods are discussed with several examples, applications, and a brief description of underlying theory. The importance of surfaces in microsystems and nanosystems and the applicability of controlling surface properties in a systematic manner for both fundamental science and applied studies is also discussed. The readers are pointed to several pioneering research efforts over the years that have made surface modification and surface science a rich, diverse, and multidisciplinary research field. It is hoped that this report will assist researchers from diverse fields by providing a collection of varied references and encourage the next generation of surface scientists and engineers to significantly advance the state of knowledge.