Papers by Sankha Banerjee
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).
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.
Journal of Materials Science: Materials in Electronics, 2019
We have simulated the operation and functionality of a working Bi-based perovskite solar cell dev... more We have simulated the operation and functionality of a working Bi-based perovskite solar cell device using GPVDM and compared it against a Pb-based device. The results are extremely promising in that they showcase comparable cell efficiencies, with the Bi-based device showing a highest 20.0% efficiency (Jsc of 256 A.m-2, Voc of 1.04 V, FF of 0.75) at 450 nm active layer thickness compared to 23.4% of its Pb counterpart (Jsc of 349.3 A.m-2, Voc of 0.81 V, FF of 0.83) at 850 nm active layer thickness. The Bi-based device can thus be manufactured at approximately half its Pb-counterpart active layer thickness, to give its optimal efficiency value. A deeper study of each of the Jsc, Voc and FF trends provide keen insight into charge transfer kinetics within the device, paving the way to optimal experimental setups for fabricating the most efficient non-toxic perovskite devices.
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...
Journal of Manufacturing Science and Engineering, 2006
Machining of materials has received substantial attention due to the increasing use of machining ... more Machining of materials has received substantial attention due to the increasing use of machining processes in various industrial applications. The research in this area is intended mainly to improve the machining of process so as to achieve the required surface quality. Machining processes, though employed widely as in metal removal process, have their own share of problems, such as high machining zone temperature, which may lead to poor surface quality. Machining fluids are applied in different forms to control such a high temperature, but they are partially effective within a narrow working range; recent studies also indicate their polluting nature. Solid lubricant assisted machining is a novel concept to control the machining zone temperature without polluting the environment. Solid lubricant, if employed properly, could control the machining zone temperature effectively by intensive removal of heat from the machining zone. A new experimental setup has been envisaged and built. E...
Ceramics International, 2015
ABSTRACT Three-phase piezoelectric composites that were comprised of PZT, nano-sized aluminum (18... more ABSTRACT Three-phase piezoelectric composites that were comprised of PZT, nano-sized aluminum (18 nm) and Portland cement were prepared via a normal mixing and spreading method. The volume fraction of Al was held constant at 0.02, while the volume fraction of PZT was varied from 0.10 to 0.70. The dielectric constant, tan (δ), and piezoelectric coefficient were experimentally investigated as a function of PZT volume fraction, and were found to possess higher dielectric constants, than their two-phase counterparts (PZT and Portland cement). A comprehensive age study of the piezoelectric and dielectric properties is presented, where significant reductions in material performance occurred within 2 days of sample preparation, and to a lesser degree after 400 days for piezoelectric properties. Properties of the composites are believed to be influenced by the oxidation of aluminum by the alkaline constituents in the cement matrix, distribution of fillers within the cement matrix and air voids.
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...
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 Engineering Materials and Technology
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 ~...
Energy and Environment Focus, 2013
Three-phase, PZT(PbZr 0.52 Ti 0.48 O 3)-Epoxy-Multi-walled Carbon-Nanotube (MWCNT) flexible films... more Three-phase, PZT(PbZr 0.52 Ti 0.48 O 3)-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 m. 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 ∼4353, ∼ 1945 and ∼ 61, for samples having graphene, graphene-PMMA and no electrode respectively. Similarly, composite films with graphene electrodes produced strain coefficients, e.g., d 33 and d 31 that were larger than their counterparts. Sample surface morphology and sample composition were observed using SEM and measured using Raman Spectroscopy respectively. Improved dielectric properties observed for samples with graphene coatings are due to graphene's high carrier mobility and ability to readily conform to the surface of the sample.
Journal of Engineering Materials and Technology, 2011
An analytical expression for prediction of the effective dielectric constant of a three phase 0-3... more An analytical expression for prediction of the effective dielectric constant of a three phase 0-3-0 ferroelectric composite is presented. The analytical results are verified with the experimental results from Nan et al. (2002, “Three-Phase Magnetoelectric Composite of Piezoelectric Ceramics, Rare-Earth Iron Alloys, and Polymer,” Appl. Phys. Lett., 81(20), p. 3831). The analytical model is extended to include the shape of a third phase inclusion to examine the influence of the shape (of the inclusion) on the effective dielectric constant of the composite. The dielectric constant increases as much as seven times when the aspect ratio of the conducting inclusion particle is increased from 1 (sphere) to 10 (spheroid). A comparison of the analytical predictions with the experimental values, which indicate that the increase in aspect ratio of the inclusions has a significant effect on the overall dielectric constant of the composite.
Journal of Electroceramics, 2013
Advances in Cement Research, 2014
Novel three-phase piezoelectric composites that comprised lead zirconate titanate (PZT), aluminiu... more Novel three-phase piezoelectric composites that comprised lead zirconate titanate (PZT), aluminium and Portland cement were fabricated at a low poling voltage of 0·6 kV/mm and temperature of 160°C. Aluminium and PZT particles were distributed in a Portland cement matrix, and the dielectric constant, tan δ and strain coefficients were experimentally investigated as a function of inclusion volume fraction. The three-phase piezoelectric composites were found to possess higher piezoelectric strain coefficients, d33, than their two-phase counterparts (PZT and Portland cement composites). The highest value of d33 observed for the three-phase composite was 8·1 pC/N for volume fractions of 0·7 and 0·2 for PZT and aluminium respectively, which was 164% of the value observed for the two-phase composite, at the same PZT volume fraction. An analytical model was used to predict values for the effective dielectric constant of the three-phase composites, and these values compared reasonably well t...
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.
Water environment research : a research publication of the Water Environment Federation, 2021
Researchers are trying to tackle water scarcity in numerous ways. One of those ways is the use of... more Researchers are trying to tackle water scarcity in numerous ways. One of those ways is the use of nanotechnology in water processing and purification. The current work involves the fabrication and optimization of activated carbon and graphene-based hybrid water purification system. Five different concentrations of methylene blue and deionized water (DI) water dye solutions were used, and they were filtered in three different cycles. For the potential usage on the consumer side, a small-scale, low-cost water filter is developed using activated carbon, commercial filter paper, and graphene nanoplatelets. The filter paper is used to hold mixtures of the activated carbon and graphene nanoplatelets within the water filter. The conductivity, TDS, and pH are measured for the feed water and the processed water using an Oakton EcoTestr and Apera Instruments PH60 Premium Pocket pH meter respectively. A UV-Vis spectrometer is used to measure the absorption of solutions. The distribution and ad...
Perovskite oxides have been used as sensors, actuators, transducers, for sound generation and det... more Perovskite oxides have been used as sensors, actuators, transducers, for sound generation and detection, and also in optical instruments and microscopes. Perovskite halides are currently considered as optoelectronic devices such as solar cells, photodetectors, and radiation detection, but there are major issues with stability, interfacial recombination, and electron/hole mobility. The following work looks into the fabrication of non-toxic ZnO-based lead-free alternatives to perovskite oxides for use as secondary sensors or electron transport layers along with perovskite halides for application in stacked biomedical wearable devices. Three-phase, lead-free, Zinc Oxide-Graphene-Epoxy electroactive nanocomposite thin films were fabricated. The volume fraction of the Graphene phase was held constant at 10%, while the volume fraction of the ZnO phase was varied from 10–70%. The dielectric constant, capacitance, impedance, resistance, and conductance of the samples were measured using an ...
Journal of Engineering Materials and Technology, Oct 1, 2011
Two-phase PZT-epoxy piezoelectric composites and three phase PZT-epoxy-Al composites were fabrica... more Two-phase PZT-epoxy piezoelectric composites and three phase PZT-epoxy-Al composites were fabricated using a poling voltage of 0.2 kV/mm. The influence of aluminum inclusion size (nano and micron) and (lead zirconate titanate) PZT volume fraction on the dielectric properties of the three phase PZT-epoxy-aluminum composites were experimentally investigated. In general, dielectric and piezoelectric properties of the PZT-epoxy matrix were improved with the addition of aluminum particles. Composites that were comprised of ...
Journal of Nanomaterials, Sep 30, 2018
PZT-epoxy-multiwalled carbon nanotube (MWCNT) flexible thick film actuators were fabricated using... more PZT-epoxy-multiwalled carbon nanotube (MWCNT) flexible thick film actuators were fabricated using a sol-gel and spin coat and deposition process. Films were characterized in terms of their piezoelectric and dielectric properties as a function of MWCNT volume fraction and polarization process. Correlations between surface treatment of the MWCNTs and composite performance were made. The surface morphology and filler distribution were observed with the aid of SEM and TEM images. The volume fraction of PZT was held constant at 30%, and the volume fraction of MWCNTs varied from 1% to 10%. Two forms of dielectric polarization were compared. Corona discharge polarization induced enhanced piezoelectric and dielectric properties by a factor of 10 in comparison to the parallel-plate contact method (piezoelectric strain coefficient and dielectric constant were 0.59 pC/N and 61.81, respectively, for the parallel-plate contact method and 9.22 pC/N and 103.59 for the corona polarization method, respectively). The percolation threshold range was observed to occur at a MWCNT volume fraction range between 5% and 6%.
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Papers by Sankha Banerjee