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5. Smartphone-based colorimetric determination of some physicochemical properties of polyaniline on flexible cellulose substrate

Author

Das, Kaushik, Bhattacharya, Pujan Sankar, Das, Jayanta, Dasgupta, Debadrita, and Saha, Biswajit

Subjects
Cellulose -- Electric properties -- Analysis, Polymerization -- Electric properties -- Analysis, Electronic equipment and supplies -- Electric properties -- Analysis, Public software -- Analysis -- Electric properties, Smart phones -- Analysis -- Electric properties, Smart phone, Open source software, Engineering and manufacturing industries, Science and technology
Abstract

Polymer-based materials are of high potential for application as active materials in contemporary electronic gadgets. The functionality of such materials is highly dependent on their oxidation state and requires fine control during their synthesis. Owing to that, we have designed a cost-effective, simple, portable, system for calibration and the detection of the optical and electrical properties of polyaniline loaded on a paper substrate using a smartphone-based colorimetric sensor. The vapor phase polymerization technique was adopted for preparing polyaniline. Colorimetric measurements of polyaniline-loaded papers were achieved by estimating the hue, saturation and value (HSV) color parameter values using an open-source smartphone application called 'Color Grab (Color Detection)' during synthesis at different time intervals. The proposed sensor relies on the principle of Beer-Lambert law. The rear camera of the smartphone acts as a sensor and captures the light signal from the samples and provides information to the colorimetric app. The colorimetric results showed a promising correlation between the color parameter values with their electrical properties. The optical absorbance results of all polyaniline-loaded papers are also in accordance with the H parameter values. The proposed sensor can be used as a portable smartphone-based point-of-care testing kit to bring in-situ control during synthesis. Highlights * Conducting polymer on flexible cellulose substrate. * Smartphone-based visual colorimetric sensor. * Biodegradable and environment-friendly electronic material. * Variation of electrical properties in terms of hue values. * Cheap, portable sensor for point-of-care testing. KEYWORDS charge transport, colorimetry, conducting polymer, point-of-care testing, portable, smartphone application, 1 | INTRODUCTION The evolution of polymers is now an emerging topic in the field of materials and nanoscience. Different polymer materials are evolving for application in electronic and optoelectronic [...]

Published
2024
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6. Optimized EEG based mood detection with signal processing and deep neural networks for brain-computer interface

Author

Adhikary, Subhrangshu, Jain, Kushal, Saha, Biswajit, and Chowdhury, Deepraj

Subjects
Quantitative Biology - Neurons and Cognition, Computer Science - Artificial Intelligence, Computer Science - Human-Computer Interaction, Electrical Engineering and Systems Science - Signal Processing
Abstract

Electroencephalogram (EEG) is a very promising and widely implemented procedure to study brain signals and activities by amplifying and measuring the post-synaptical potential arising from electrical impulses produced by neurons and detected by specialized electrodes attached to specific points in the scalp. It can be studied for detecting brain abnormalities, headaches, and other conditions. However, there are limited studies performed to establish a smart decision-making model to identify EEG's relation with the mood of the subject. In this experiment, EEG signals of 28 healthy human subjects have been observed with consent and attempts have been made to study and recognise moods. Savitzky-Golay band-pass filtering and Independent Component Analysis have been used for data filtration.Different neural network algorithms have been implemented to analyze and classify the EEG data based on the mood of the subject. The model is further optimised by the usage of Blackman window-based Fourier Transformation and extracting the most significant frequencies for each electrode. Using these techniques, up to 96.01% detection accuracy has been obtained.

Published
2023
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20. Removal of instabilities of the higher derivative theories in the light of antilinearity

Author

Paul, Biswajit, Dhar, Himangshu, and Saha, Biswajit

Subjects
High Energy Physics - Theory
Abstract

Theories with higher derivatives involve linear instabilities in the Hamiltonian commonly known as Ostrogradski ghosts and can be viewed as a very serious problem during quantization. To cure {this} , we have considered the properties of antilinearty that can be found inherently in the non-Hermitian Hamiltonians. Owing to the existence of antilinearity, we can construct an operator, called the $V$-operator, which acts as an intertwining operator between the Hamiltonian and its hermitian conjugate. We have used this $V$-operator to remove the linear momenta term from the higher derivative Hamiltonian by making it non-Hermitian in the first place via an isospectral similarity transformation. The final form of the Hamiltonian is free from the Ostrogradski ghosts under some restriction on the mass term., Comment: 12 pages, Latex, updated version

Published
2021
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25. Ghosts in higher derivative Maxwell-Chern-Simon's theory and $\mathcal{PT}-$symmetry

Author

Paul, Biswajit, Dhar, Himangshu, and Saha, Biswajit

Subjects
High Energy Physics - Theory, Quantum Physics
Abstract

Ghost fields in quantum field theory have been a long-standing problem. Specifically, theories with higher derivatives involve ghosts that appear in the Hamiltonian in the form of linear momenta term, which is commonly known as the Ostrogradski ghost. Higher derivative theories may involve both types of constraints i.e. first class and second class. Interestingly, these higher derivative theories may have non-Hermitian Hamiltonian respecting $\mathcal{PT}-$symmetries. In this paper, we have considered the $\mathcal{PT}-$symmetric nature of the extended Maxwell-Chern-Simon's theory and employed the second class constraints to remove the linear momenta terms causing the instabilities. We found that the removal is not complete rather conditions arise among the coefficients of the operator ${Q}$., Comment: 11 page, Latex

Published
2020
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37. Treating Ostrogradski instability for Gallilean invariant Chern Simon's model via \mathcal{PT} symmetry

Author

Paul, Biswajit, Dhar, Himangshu, Chowdhury, Mangobinda, and Saha, Biswajit

Subjects
High Energy Physics - Theory
Abstract

The Ostrogradski ghost problem that appears in higher derivative theories containing constraints has been considered here. Specifically we have considered systems where only the second class constraints appear. For these kind of systems, it is not possible to gauge away the linear momenta that cause the instability. To solve this issue, we have considered the PT symmetric aspects of the theory. As an example we have considered the Galilean invariant Chern Simons model in $2+1$ D which is a purely second class system. By solving the constraints, in the reduced phasespace, we have derived the \p similarity transformed Hamiltonian and putting conditions on we found that the final form of the Hamiltonian is free from any linear momenta and bounded from below., Comment: 13 pages, Latex, Subsection added

Published
2018
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