34 results on '"Arindam Ghosh"'
Search Results
2. Brewing and biochemical characterization of Camellia japonica petal wine with comprehensive discussion on metabolomics
- Author
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Soumya Majumder, Malay Bhattacharya, SOURAV CHAKRABORTY, and Arindam Ghosh
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Nutrition and Dietetics ,Public Health, Environmental and Occupational Health ,Food Science - Abstract
A novel wine has been developed from Camellia japonica’s petal by fermenting the decoction with Saccharomyces cerevisiae or brewer’s yeast. pH, brix, specific gravity and alcohol percentage were tested to study the physicochemical properties of the wine. Qualitative tests indicated presence of phenols such as flavonoids, coumarins; protein; glycosides; glycerin; terpenoids; steroids; and fatty acids in the wine. Total phenol content was found high in the decoction and in its fermented form as well. In vitro biological activities such as antioxidant activity, antidiabetic activity and lipid peroxidation inhibition power were assessed in samples. Furthermore, GC-MS analysis helped to detect volatiles present in the unfermented decoction and understand the effect of fermentation on its changing metabolome while column chromatography assisted the separation of solvent-based fractions. Notable outcomes from this study were detection of bioactive compound quinic acid in the decoction and a proposed pathway of its metabolic breakdown after fermentation. Results of this research revealed biochemical and physicochemical acceptability of this wine prepared from an underutilized flower. Graphical Abstract
- Published
- 2022
3. Graphene- and metal-induced energy transfer for single-molecule imaging and live-cell nanoscopy with (sub)-nanometer axial resolution
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Narain Karedla, Alexey I. Chizhik, Jörg Enderlein, and Arindam Ghosh
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Data Analysis ,Fluorescence-lifetime imaging microscopy ,Materials science ,Microscope ,Cell Survival ,General Biochemistry, Genetics and Molecular Biology ,Madin Darby Canine Kidney Cells ,law.invention ,User-Computer Interface ,03 medical and health sciences ,Dogs ,Imaging, Three-Dimensional ,0302 clinical medicine ,Optics ,law ,Cell Line, Tumor ,Microscopy ,Animals ,Humans ,Nanotechnology ,Fluorescent Dyes ,030304 developmental biology ,0303 health sciences ,business.industry ,Bilayer ,Resolution (electron density) ,Single Molecule Imaging ,Optical axis ,Interferometry ,Energy Transfer ,Microscopy, Fluorescence ,Metals ,Graphite ,business ,030217 neurology & neurosurgery - Abstract
Super-resolution fluorescence imaging that surpasses the classical optical resolution limit is widely utilized for resolving the spatial organization of biological structures at molecular length scales. In one example, single-molecule localization microscopy, the lateral positions of single molecules can be determined more precisely than the diffraction limit if the camera collects individual photons separately. Using several schemes that introduce engineered optical aberrations in the imaging optics, super-resolution along the optical axis (perpendicular to the sample plane) has been achieved, and single-molecule localization microscopy has been successfully applied for the study of 3D biological structures. Nonetheless, the achievable axial localization accuracy is typically three to five times worse than the lateral localization accuracy. Only a few exceptional methods based on interferometry exist that reach nanometer 3D super-resolution, but they involve enormous technical complexity and restricted sample preparations that inhibit their widespread application. We developed metal-induced energy transfer imaging for localizing fluorophores along the axial direction with nanometer accuracy, using only a conventional fluorescence lifetime imaging microscope. In metal-induced energy transfer, experimentally measured fluorescence lifetime values increase linearly with axial distance in the range of 0-100 nm, making it possible to calculate their axial position using a theoretical model. If graphene is used instead of the metal (graphene-induced energy transfer), the same range of lifetime values occurs over a shorter axial distance (~25 nm), meaning that it is possible to get very accurate axial information at the scale of a membrane bilayer or a molecular complex in a membrane. Here, we provide a step-by-step protocol for metal- and graphene-induced energy transfer imaging in single molecules, supported lipid bilayer and live-cell membranes. Depending on the sample preparation time, the complete duration of the protocol is 1-3 d.
- Published
- 2021
4. Jordan Left {g, h}-Derivation over Some Algebras
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Arindam Ghosh and Om Prakash
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Combinatorics ,Tensor product ,Applied Mathematics ,General Mathematics ,010103 numerical & computational mathematics ,Commutative ring ,0101 mathematics ,Algebra over a field ,01 natural sciences ,Mathematics - Abstract
In this article, left {g, h}-derivation and Jordan left {g, h}-derivation on algebras are introduced. It is shown that there is no Jordan left {g, h}-derivation over $${{\cal M}_n}\left(C \right)$$ and ℍℝ, for g ≠ h. Examples are given which show that every Jordan left {g, h}-derivation over $${{\cal T}_n}\left(C \right)$$ , $${{\cal M}_n}\left(C \right)$$ and ℍℝ are not left {g, h}-derivations. Also, the Jordan left {g, h}-derivations over $${{\cal T}_n}\left(C \right)$$ , $${{\cal M}_n}\left(C \right)$$ and ℍℝ are right centralizers, where C is a 2-torsionfree commutative ring. Moreover, we prove the result of Jordan left {g, h}-derivation to be a left {g, h}-derivation over tensor products of algebras as well as for algebra of polynomials.
- Published
- 2020
5. Editorial
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Rajendra Singh, Tanusri Saha Dasgupta, Arindam Ghosh, Avinash Mahajan, and A K Ganguli
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Mechanics of Materials ,General Materials Science - Published
- 2022
6. Traveling wave solution and Painleve’ analysis of generalized fisher equation and diffusive Lotka–Volterra model
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Sarit Maitra, Arindam Ghosh, and Soumen Kundu
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0209 industrial biotechnology ,Control and Optimization ,Mechanical Engineering ,Mathematical analysis ,Hyperbolic function ,Fisher equation ,Monotonic function ,02 engineering and technology ,Volterra equations ,01 natural sciences ,Plot (graphics) ,020901 industrial engineering & automation ,Control and Systems Engineering ,Modeling and Simulation ,0103 physical sciences ,Traveling wave ,Electrical and Electronic Engineering ,Diffusion (business) ,010301 acoustics ,Civil and Structural Engineering ,Mathematics - Abstract
In this paper, we have obtained the traveling wave solution for generalized Fisher equation and Lotka–Volterra (L-V) model with diffusion using hyperbolic function method. The Painleve’ analysis has been used to check both of the system’s integrability. Obtained solutions have also been plotted to represent their spatio-temporal dependence. The three dimensional plot shows a monotonic profile of the solutions.
- Published
- 2020
7. HumanSense: a framework for collective human activity identification using heterogeneous sensor grid in multi-inhabitant smart environments
- Author
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Sujoy Saha, Amartya Chakraborty, Mousumi Saha, Joydeep Kumbhakar, and Arindam Ghosh
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business.industry ,Computer science ,Sensor grid ,Mobile computing ,020206 networking & telecommunications ,02 engineering and technology ,Management Science and Operations Research ,Library and Information Sciences ,Computer Science Applications ,Identification (information) ,Hardware and Architecture ,Home automation ,Human–computer interaction ,020204 information systems ,0202 electrical engineering, electronic engineering, information engineering ,Smart environment ,business ,Interpersonal interaction ,Wearable technology ,Assisted living - Abstract
Identification of human activity considering social interactions and group dynamics non-intrusively has been one of the fundamental problems and a challenging area of research. In real life, it is required for designing human-centric applications like assisted living, health care, and creating a smart home environment. As human beings spend 90% of time indoors, such a system will be helpful to monitor the behavioral anomalies of the inhabitants. Existing approaches have used intrusive or invasive methods like camera or wearable devices. In this work, we present a device-free, non-invasive, and non-intrusive sensing framework called HumanSense using an array of heterogeneous sensor grid for human activity monitoring. The sensor grids, comprising the ultrasonic and sound sensors, have been deployed for collective sensing combining a person’s physical activity and verbal interaction information. The proposed system senses a stream of events when the occupant(s) perform different physical activities categorized as atomic and group activities like sitting, standing, and walking. Simultaneously, it also tracks person-person verbal interactions such as monologue and discussion. Both information are then integrated into a single framework to understand the overall behavioral scenario of the indoor environment. The experimental results have shown that HumanSense can detect different activities with accuracy more than 90% and also improves overall identification accuracy compared to existing works. Our developed system can be further evolved into ready-to-deploy smart sensing panels which can be effective for human activity monitoring in an indoor environment.
- Published
- 2020
8. Predictors of Leak After Colorectal Anastomoses: a Case Series Analysis
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Shiv Kishor, Harpal Singh, Arindam Ghosh, and Anil Kumar
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medicine.medical_specialty ,business.industry ,Ileocolic artery ,Anastomosis ,medicine.disease ,Colorectal surgery ,Cardiac surgery ,Surgery ,Plastic surgery ,Cardiothoracic surgery ,medicine.artery ,Pediatric surgery ,Medicine ,Hypoalbuminemia ,business - Abstract
Anastomotic leak (AL) is a major morbid complication after colorectal surgery. There are only few articles to find the predictors of leak after colorectal anastomoses that have been published in the literature. The aim of this study is to identify different predictors for colorectal AL in Indian set up. Historical data were collected from the hospital record of patients from June 2005 to April 2014. In prospective period, from May 2014 to February 2016, colorectal surgery patients were recruited to collect the data. Various preoperative, intraoperative, and postoperative factors for AL were analyzed using Student’s t test and Chi square test. The p value less than 0.05 was considered statistically significant for all results. The AL rate was 9.1%. The predictors for AL were comorbidities like cerebrovascular accident (CVA) (p
- Published
- 2020
9. Anomalous electrical transport in orientationally controlled trinary hybrids of graphene and twisted bilayer molybdenum disulphide
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Manish Jain, Arindam Ghosh, Navkiranjot Kaur Gill, Sudipta Kundu, Saloni Kakkar, and Shaili Sett
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Superconductivity ,Materials science ,Condensed matter physics ,Graphene ,Superlattice ,Bilayer ,Substrate (electronics) ,law.invention ,Mechanics of Materials ,law ,Density of states ,General Materials Science ,Density functional theory ,Electronic band structure - Abstract
Moire superlattices of two-dimensional (2D) materials oriented at low twist angles generate a large-scale interference pattern leading to strong interlayer coupling, which influences the band structure and introduces flatbands. Conventional electronic transport measurements have shown the effects of flatband physics, manifesting as correlated insulating states and emergent superconductivity. In this study, we probe the electronic states in a trinary hybrid of graphene and twisted bilayer (tbl) MoS2. Graphene acts as a sensing layer, which captures the electronic effects of the underlying substrate, and we observe certain anomalies in the electronic characteristics of graphene only in the presence of an underlying 58.5 $$^\circ$$ tbl MoS2, at low temperatures. Interestingly, graphene on tbl MoS2, with twist angle near 0 $$^\circ$$ or on natural bilayer MoS2, does not show any anomalies. Density functional theory calculations show several distinguishable peaks in the density of states at the conduction band edge of twisted MoS2 near 60 $$^\circ$$ . We speculate that the anomaly appears due to fermi level pinning of graphene owing to a large density of states in the flatbands of twisted bilayer MoS2. An analysis of the energetics in the graphene-MoS2 hybrid quantitatively agree with theoretical predictions.
- Published
- 2021
10. Production of fermented tea petal decoction with insights into in vitro biochemical tests, antioxidant assay and GC-MS analysis
- Author
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Sahadeb Sarkar, Sumedha Saha, Sukanya Acharyya, Soumya Majumder, Malay Bhattacharya, Sourav Chakraborty, and Arindam Ghosh
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Tea petal ,Antioxidant ,medicine.medical_treatment ,Decoction ,Food processing and manufacture ,chemistry.chemical_compound ,Fermented tea ,medicine ,Tannin ,TX341-641 ,Food science ,chemistry.chemical_classification ,Wine ,Nutrition and Dietetics ,Ethanol ,Nutrition. Foods and food supply ,fungi ,Public Health, Environmental and Occupational Health ,food and beverages ,Glycoside ,TP368-456 ,brewer’s yeast ,chemistry ,Fermentation ,GC-MS ,Food Science - Abstract
Abstract This research work was designed to attempt and propose the first report on production and biochemical characterization of fermented tea flower petal decoction or simply tea petal wine. The tea petal decoction and brewer’s yeast or Saccharomyces cerevisiae were co-cultured for fermentation. Antioxidant activity and chromatographic separation of potential candidates were assessed. Primary investigations for qualitative characters on this fermented broth revealed the presence of steroids, tannin, flavonoids, phenol, cardiac glycosides, coumarin, caffeine etc. Our manufactured fermented broth showed high free radical scavenging activity after 2 months of aging. High DPPH scavenging activities were also observed in solvent fractions of acetone, ethanol and methanol. The antioxidant activity, alcohol percentage and other qualities were seen to be gradually increased during aging. Gas chromatography-mass spectrometry analysis revealed the presence of 44 compounds including many potential antioxidant molecules and other bioactive agents. Hopefully, presence of alcohol with medicinally active compounds and antioxidant activity will make it as acceptable as a good wine and tea flower as economically functional. Graphical abstract
- Published
- 2021
11. The first integral method and some nonlinear models
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Sarit Maitra and Arindam Ghosh
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010302 applied physics ,Physics ,Vries equation ,Partial differential equation ,Applied Mathematics ,010102 general mathematics ,Mathematical analysis ,01 natural sciences ,Shock (mechanics) ,Exponential function ,Computational Mathematics ,Nonlinear system ,Nonlinear Sciences::Exactly Solvable and Integrable Systems ,0103 physical sciences ,0101 mathematics ,Integral method - Abstract
In this article, first integral method [Ref. : Feng. Z., Journal of Physics A: Mathematical and General, 35(2002), 343–349] is used to find exact solutions of some nonlinear partial differential equations. It is applied to find exact solutions to a variant Boussinesq equation, the extended modifed Korteweg-de Vries equation and the Kudryashov–Sinel’shchikov equation. The properties of solutions are then discussed and plotted by using suitable values of the parameters involved. Shock wave-like solutions for variant Boussinesq and extended mKdv equations are found. For the Kudryashov–Sinel’shchikov equation one singular and two exponential solutions are obtained.
- Published
- 2021
12. Metabolomics of potential contenders conferring antioxidant property to varied polar and non-polar solvent extracts of Edgaria darjeelingensis C.B.Clarke
- Author
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Sourav Chakraborty, Sumedha Saha, Malay Bhattacharya, Arindam Ghosh, and Soumya Majumder
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0106 biological sciences ,Edgaria darjeelingensis ,Antioxidant ,medicine.medical_treatment ,Flavonoid ,01 natural sciences ,Endemic ,03 medical and health sciences ,chemistry.chemical_compound ,Phytol ,010608 biotechnology ,medicine ,Acetone ,Organic chemistry ,GC–MS ,Solubility ,lcsh:Science ,030304 developmental biology ,General Environmental Science ,chemistry.chemical_classification ,0303 health sciences ,Endangered ,Terpenoid ,Solvent ,chemistry ,General Earth and Planetary Sciences ,lcsh:Q ,Methanol ,Pathway - Abstract
Background The Himalaya hotspot, habitat to numerous indigenous species, harbours an endemic and endangered, cucurbit climber Herpetospermum darjeelingense (C.B.Clarke) H.Schaef. & S.S.Renner [Edgaria darjeelingensis C.B.Clarke]. Seeds of this plant have traditionally been used for ethno-veterinary treatment. The present probe aims to provide an insight into the antioxidant-related biochemical attributes of this phytochemically unexplored plant. Results DPPH scavenging activity of solvent extracts showed more potential towards the polar end with its maximum activity in methanolic extract (84.64%). Acetone extract showed more ferric reducing power than the ethanol fractions. Maximum flavonoid quantification was recorded in ethanol extract. GC–MS of methanolic extract detected 39 compounds of which 22 have preventive and curing properties for several ailments. Thirteen compounds were reported with antioxidant activity and cover an area of 63.92% among the total detected compounds by GC–MS. 1,3,4,5-Tetrahydroxy-cyclohexanecarboxylic acid; Hexadecanoic acid, methyl ester; ß sitosterol and Phytol are present in significant quantity and are the prime candidates conferring antioxidant potential. Chromatographically fractionalized methanol extract with non-polar to polar solvents and their subsequent DPPH scavenging analysis exhibited a major peak in ethanol fraction due to the presence of Phytol in considerable high quantity and some other compounds. Further sub-fractionation of ethanolic fraction provides a supportive evidence of ethanol solubility of the compounds. Biosynthetic lineage reveals fatty acid synthesis, intermediates of Shikimate pathway and terpenoid metabologenesis schemes lead to the several antioxidant molecules detected in our extract. Conclusion Metabolomics of antioxidants will provide a better understanding in its intracellular free radical quenching activity and isolation of these bioactive compounds can boost pharmaceutical industry.
- Published
- 2021
13. Graphene functionalized field-effect transistors for ultrasensitive detection of Japanese encephalitis and Avian influenza virus
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Saurav Islam, Arindam Ghosh, Subeer S. Majumdar, Akanksha Roberts, Neha Chauhan, Sonu Gandhi, Subhasis Mahari, Bhaskar Ghawri, and Ravi Kumar Gandham
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0301 basic medicine ,Materials science ,Transistors, Electronic ,viruses ,lcsh:Medicine ,Nanotechnology ,Microscopy, Atomic Force ,Article ,law.invention ,Nanomaterials ,Birds ,03 medical and health sciences ,symbols.namesake ,0302 clinical medicine ,law ,Spectroscopy, Fourier Transform Infrared ,medicine ,Animals ,Encephalitis, Japanese ,lcsh:Science ,Detection limit ,Multidisciplinary ,Bioconjugation ,Graphene ,lcsh:R ,Nanobiotechnology ,Japanese encephalitis ,medicine.disease ,030104 developmental biology ,Influenza in Birds ,Microscopy, Electron, Scanning ,symbols ,Graphite ,lcsh:Q ,Field-effect transistor ,Raman spectroscopy ,Biosensor ,030217 neurology & neurosurgery - Abstract
Graphene, a two-dimensional nanomaterial, has gained immense interest in biosensing applications due to its large surface-to-volume ratio, and excellent electrical properties. Herein, a compact and user-friendly graphene field effect transistor (GraFET) based ultrasensitive biosensor has been developed for detecting Japanese Encephalitis Virus (JEV) and Avian Influenza Virus (AIV). The novel sensing platform comprised of carboxy functionalized graphene on Si/SiO2 substrate for covalent immobilization of monoclonal antibodies of JEV and AIV. The bioconjugation and fabrication process of GraFET was characterized by various biophysical techniques such as Ultraviolet–Visible (UV–Vis), Raman, Fourier-Transform Infrared (FT-IR) spectroscopy, optical microscopy, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The change in the resistance due to antigen–antibody interaction was monitored in real time to evaluate the electrical response of the sensors. The sensors were tested in the range of 1 fM to 1 μM for both JEV and AIV antigens, and showed a limit of detection (LOD) upto 1 fM and 10 fM for JEV and AIV respectively under optimised conditions. Along with ease of fabrication, the GraFET devices were highly sensitive, specific, reproducible, and capable of detecting ultralow levels of JEV and AIV antigen. Moreover, these devices can be easily integrated into miniaturized FET-based real-time sensors for the rapid, cost-effective, and early Point of Care (PoC) diagnosis of JEV and AIV.
- Published
- 2020
14. Tailoring phonon modes of few-layered MoS2 by in-plane electric field
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Achintya Singha, Arindam Ghosh, Shib Shankar Singha, Sreemanta Mitra, Divya Srivastava, Maarit Karppinen, S. Dutta, Biswarup Satpati, Bose Institute, Department of Chemistry and Materials Science, University of Calcutta, Saha Institute of Nuclear Physics, Indian Institute of Science Bangalore, Aalto-yliopisto, and Aalto University
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Materials science ,Phonon ,Point reflection ,02 engineering and technology ,010402 general chemistry ,Space (mathematics) ,01 natural sciences ,lcsh:Chemistry ,symbols.namesake ,Electric field ,lcsh:TA401-492 ,General Materials Science ,Condensed matter physics ,Mechanical Engineering ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Piezoelectricity ,0104 chemical sciences ,lcsh:QD1-999 ,Nanoelectronics ,Mechanics of Materials ,symbols ,lcsh:Materials of engineering and construction. Mechanics of materials ,0210 nano-technology ,Raman spectroscopy ,Intensity (heat transfer) - Abstract
We discuss the effect of the in-plane electric field on the Raman spectroscopy for few-layered MoS2. The characteristic Raman modes of MoS2 show gradual red shift, while the intensity increases by 45–50% as the electric field is increased, showing a large electro-optical effect. Structural analysis suggests that our few-layered MoS2 belongs to P6/m2 space group with broken inversion symmetry. We attribute this gradual red shift to this broken symmetry-driven piezoelectricity in MoS2, which generates tensile strain along the perpendicular direction when the electric field is applied. The enhancement of the effect upon reversing the electric field direction adds credence to our interpretation. Our first principal density-functional theory calculation further substantiates the claim. This optical probing of the electromechanical coupling may lead to applications as a nonextensive technique for electric field/strain sensors in the nanoelectronics devices.
- Published
- 2020
15. Low Power, CMOS-MoS2 Memtransistor based Neuromorphic Hybrid Architecture for Wake-Up Systems
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Pratik Kumar, Chetan Singh Thakur, Arindam Ghosh, André van Schaik, Tathagata Paul, and Sarthak Gupta
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lcsh:Medicine ,02 engineering and technology ,Two-dimensional materials ,010402 general chemistry ,01 natural sciences ,Article ,Bottleneck ,Electronic Systems Engineering (Formerly Centre for Electronic Design & Technology) ,Electronic devices ,lcsh:Science ,Block (data storage) ,Multidisciplinary ,Physics ,lcsh:R ,Energy consumption ,021001 nanoscience & nanotechnology ,Electrical and electronic engineering ,0104 chemical sciences ,Power (physics) ,Architecture framework ,CMOS ,Computer architecture ,Neuromorphic engineering ,lcsh:Q ,0210 nano-technology ,Realization (systems) - Abstract
Neuromorphic architectures have become essential building blocks for next-generation computational systems, where intelligence is embedded directly onto low power, small area, and computationally efficient hardware devices. In such devices, realization of neural algorithms requires storage of weights in digital memories, which is a bottleneck in terms of power and area. We hereby propose a biologically inspired low power, hybrid architectural framework for wake-up systems. This architecture utilizes our novel high-performance, ultra-low power molybdenum disulphide (MoS2) based two-dimensional synaptic memtransistor as an analogue memory. Furthermore, it exploits random device mismatches to implement the population coding scheme. Power consumption per CMOS neuron block was found to be 3 nw in the 65 nm process technology, while the energy consumption per cycle was 0.3 pJ for potentiation and 20 pJ for depression cycles of the synaptic device. The proposed framework was demonstrated for classification and regression tasks, using both off-chip and simplified on-chip sign-based learning techniques.
- Published
- 2019
16. Anomalous Number Fluctuation Noise in Localized Transition Metal Dichalcogenide Layers: Generalization of McWhorter’s Mechanism
- Author
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Pulickel M. Ajayan, Subhamoy Ghatak, Vidya Kochat, Chandra Sekhar Tiwary, Arindam Ghosh, Yongji Gong, Sanjeev Kaushal, Kimberly Hsieh, and Xiang Zhang
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Work (thermodynamics) ,Materials science ,Condensed matter physics ,Generalization ,Mechanical Engineering ,Oxide ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Noise (electronics) ,chemistry.chemical_compound ,chemistry ,Transition metal ,Mechanics of Materials ,0103 physical sciences ,General Materials Science ,Charge carrier ,010306 general physics ,0210 nano-technology ,Wave function ,Mechanism (sociology) - Abstract
The mechanism of electrical noise in transition metal dichalcogenides (TMDCs) has mostly been attributed to charge carrier fluctuations between the oxide traps and the conducting channel, in accordance with the McWhorter model. However, the original McWhorter model was formulated for diffusive transport with conducting carriers having extended electronic wave functions. Our work serves to generalize the McWhorter mechanism to include strongly localized systems such as the TMDC family and provides an explanation for the unusual exponential behavior of noise magnitude with temperature.
- Published
- 2018
17. Correction to: HumanSense: a framework for collective human activity identification using heterogeneous sensor grid in multi-inhabitant smart environments
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Arindam Ghosh, Amartya Chakraborty, Joydeep Kumbhakar, Mousumi Saha, and Sujoy Saha
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Hardware and Architecture ,Management Science and Operations Research ,Library and Information Sciences ,Computer Science Applications - Published
- 2020
18. UltraSense: A non-intrusive approach for human activity identification using heterogeneous ultrasonic sensor grid for smart home environment
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Sujoy Saha, Amartya Chakraborty, Dhruv Chakraborty, Mousumi Saha, and Arindam Ghosh
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General Computer Science ,business.industry ,Computer science ,010401 analytical chemistry ,Real-time computing ,Elderly care ,020206 networking & telecommunications ,Computational intelligence ,02 engineering and technology ,Grid ,01 natural sciences ,0104 chemical sciences ,Identification (information) ,Home automation ,0202 electrical engineering, electronic engineering, information engineering ,Ultrasonic sensor ,business ,Wearable technology - Abstract
Recognizing human activities non-intrusively has prevailed as a challenging and active area of research. In real life, it is a major requirement for human-centric applications like assisted living for elderly care, health-care and creating a smart home environment etc. Considering that people spend more than 90% (Klepeis et al. in J Exposure Sci Environ Epidemiol 11(3):231, 2001) of their time indoors, a proper indoor activity monitoring system will be helpful to monitor the abnormal behavior of the occupants. Existing approaches have implemented intrusive or invasive methods such as a camera or wearable devices. In this work, we present a non-invasive, non-intrusive sensing technique using an array of heterogeneous ultrasonic sensors for human activity monitoring. The ultrasonic sensors are placed in two separate deployments as sensor grids and in different positions of the door-frame. The proposed system senses a stream of events as the occupants perform different activities categorized as primary, postural and group activities. The primary activities considered are sitting, standing and fall. The postural activities are intermediate transitional states in the primary activities. These activities when performed in groups, are considered as a group activity. Other than activities it can identify different indoor movements, count room occupancy and identify occupants. Based on the collected data, the results show that the proposed system achieves an accuracy of more than 90% for detection of different activities and shows improvement over existing works. The final outcome of this work can be seen as developing the current prototype into smart ceiling panels that can be easily used in the indoor environment for human activity monitoring.
- Published
- 2019
19. Studies on frequency dependent electrical and dielectric properties of sintered zinc oxide pellets: effects of Al-doping
- Author
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S. Tewari, Ayon Bhattacharjee, and Arindam Ghosh
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010302 applied physics ,Materials science ,Dopant ,Doping ,Relaxation (NMR) ,Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,02 engineering and technology ,Dielectric ,Zinc ,Conductivity ,021001 nanoscience & nanotechnology ,01 natural sciences ,chemistry ,Aluminium ,0103 physical sciences ,Crystallite ,0210 nano-technology - Abstract
Sintered pellets of zinc oxide (ZnO), both undoped and Al-doped are prepared through a chemical process. Dopant concentration of Aluminium in ZnO [Al/Zn in weight percentage (wt%)] is varied from 0 to 3 wt%. After synthesis structural characterisation of the samples are performed with XRD and SEM-EDAX which confirm that all the samples are of ZnO having polycrystalline nature with particle size from 108.6 to 116 nm. Frequency dependent properties like a.c. conductivity, capacitance, impedance and phase angle are measured in the frequency range 10 Hz to 100 kHz as a function of temperature (in the range 25–150 °C). Nature of a.c. conductivity in these samples indicates hopping type of conduction arising from localised defect states. The frequency and temperature dependent properties under study are found to be as per correlated barrier hoping model. Dielectric and impedance properties studied in the samples indicate distributed relaxation, showing decrease of relaxation time with temperature.
- Published
- 2016
20. Collaborative model for a two-echelon supply chain with uncertain demand under carbon tax policy
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Sarada Prasad Sarmah, Arindam Ghosh, and J.K. Jha
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021103 operations research ,Multidisciplinary ,Carbon tax ,Payload ,Supply chain ,0211 other engineering and technologies ,02 engineering and technology ,Environmental economics ,Reorder point ,Tax rate ,03 medical and health sciences ,0302 clinical medicine ,Order (business) ,Greenhouse gas ,030221 ophthalmology & optometry ,Production (economics) ,Business - Abstract
Consideration of carbon policies while optimizing supply chain operations has become imperative as governments and regulatory bodies throughout the world have implemented different carbon policies to reduce emissions of greenhouse gasses, especially CO2. “Carbon tax” is one of the major carbon policies, initiated by several governments to curtail emissions. In this study, we have considered this policy to optimize the total expected cost (TEC) of a two-echelon integrated supply chain with stochastic demand, where both backorders and lost sales are permitted. An unconstrained mixed integer non-linear programming (MINLP) problem is formulated and further solved to find the optimal production rate, order quantity, number of shipments and reorder point while minimizing the TEC. Emissions from all the major sources such as production, inventory and transportation have been taken into consideration. It is assumed that the emission from production is a function of production rate, and emission from transportation depends on payload and vehicle type. This study will help organizations to reduce cost and emissions, and regulatory bodies to decide proper tax rate on carbon emission.
- Published
- 2018
21. Out-of-plane interface dipoles and anti-hysteresis in graphene-strontium titanate hybrid transistor
- Author
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Maxim Mostovoy, Arunesh Roy, Dhani Nafday, Tanusri Saha-Dasgupta, Tamalika Banerjee, Anindita Sahoo, Tathagata Paul, Arindam Ghosh, Roald Ruiter, Physics of Nanodevices, and Theory of Condensed Matter
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DEVICES ,Materials science ,SRTIO3 ,FERROELECTRICITY ,02 engineering and technology ,Dielectric ,AUGMENTED-WAVE METHOD ,01 natural sciences ,law.invention ,lcsh:Chemistry ,ELECTRONICS ,chemistry.chemical_compound ,law ,0103 physical sciences ,lcsh:TA401-492 ,General Materials Science ,OXIDES ,010306 general physics ,Polarization (electrochemistry) ,Condensed matter physics ,Graphene ,SURFACES ,Mechanical Engineering ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,DIELECTRIC-CONSTANT ,Ferroelectricity ,Polarization density ,Band bending ,lcsh:QD1-999 ,chemistry ,Mechanics of Materials ,Strontium titanate ,lcsh:Materials of engineering and construction. Mechanics of materials ,Field-effect transistor ,1/F NOISE ,FIELD-EFFECT TRANSISTORS ,0210 nano-technology - Abstract
The out-of-plane electric polarization at the surface of SrTiO3 (STO), an archetypal perovskite oxide, may stabilize new electronic states and/or host novel device functionality. This is particularly significant in proximity to atomically thin membranes, such as graphene, although a quantitative understanding of the polarization across graphene–STO interface remains experimentally elusive. Here, we report direct observation and measurement of a large intrinsic out-of-plane polarization at the interface of single-layer graphene and TiO2-terminated STO (100) crystal. Using a unique temperature dependence of anti-hysteretic gate-transfer characteristics in dual-gated graphene-on-STO field-effect transistors, we estimate the polarization to be as large as ≈12 μC cm−2, which is also supported by the density functional theory calculations and low-frequency noise measurements. The anti-hysteretic transfer characteristics is quantitatively shown to arise from an interplay of band bending at the STO surface and electrostatic potential due to interface polarization, which may be a generic feature in hybrid electronic devices from two-dimensional materials and perovskite oxides. The dipole field at the surface of SrTiO3 strongly impacts the transfer characteristics of graphene/SrTiO3 field-effect transistors. A team led by Arindam Ghosh at the Indian Institute of Science (Bangalore) fabricated dual-gated field-effect transistors with graphene on a TiO2-terminated SrTiO3 (100) crystal, and observed a large, intrinsic out-of-plane electric polarization at the hetero-interface. The measured polarization, detected by means of gate-transfer characteristics and further supported by density functional theory calculations, was found to be as large as 12 μC cm−2. The nature of the anti-hysteretic transfer characteristics in both resistance and noise is indicative of formation of trap states at the SrTiO3 interface, due to band renormalization and electrostatic confinement. These results improve the physical understanding of the interfaces between atomically thin materials and polarizable substrates.
- Published
- 2018
22. Influence of Cu doping on the structural, electrical and optical properties of ZnO
- Author
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Arindam Ghosh, Navnita Kumari, and Ayon Bhattacharjee
- Subjects
Absorbance ,Photoluminescence ,Materials science ,chemistry ,Dopant ,Band gap ,Doping ,Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Zinc ,Texture (crystalline) ,Crystallite - Abstract
Pure and Cu-doped zinc oxide (ZnO) nanoparticles were prepared using a chemical method. The dopant concentration (Cu/Zn in atomic percentage (wt%)) is varied from 0 to 3 wt%. Structural characterization of the samples performed using X-ray diffraction (XRD) confirmed that all the nanoparticles of zinc oxide are having polycrystalline nature. Morphological studies were conducted using field emission scanning electron microscopy (FESEM) to confirm the grain size and texture. Electrical measurements showed that the AC conductivity initially decreases and then rises with increasing Cu concentration. The UV–Vis studies showed absorbance peaks in the 200–800 nm region. It is found that the absorbance does not significantly change with doping. This fact is further confirmed from the band-gap calculations using the reflectance graphs. When analysed in terms of Burstein–Moss shift, an increase of band gap from 3.42 to 3.54 eV with increasing Cu concentration is observed. In the Photoluminescence (PL) studies a red-shift is observed with increasing dopant concentration.
- Published
- 2014
23. At a long-awaited turning point
- Author
-
Arindam Ghosh and Yamuna Krishnan
- Subjects
Entrepreneurship ,Biomedical Engineering ,India ,Bioengineering ,Mindset ,Nanotechnology ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,General Materials Science ,Turning point ,Engineering ethics ,Electrical and Electronic Engineering ,Translational science - Abstract
Research in nanotechnology in India is on an upswing given the substantial investments in the past two decades. Making an impact globally will now require investing in education, entrepreneurship, translational science, infrastructure for manufacturing, and changing the administrative mindset.
- Published
- 2014
24. Investigation of structural and electrical transport mechanism of SnO2 with Al dopants
- Author
-
Ayon Bhattacharjee, Arindam Ghosh, and Navnita Kumari
- Subjects
chemistry.chemical_compound ,Materials science ,chemistry ,Tin dioxide ,Doping ,Energy-dispersive X-ray spectroscopy ,Analytical chemistry ,General Physics and Astronomy ,Grain boundary ,Electrical measurements ,Crystallite ,Atmospheric temperature range ,Polaron - Abstract
Undoped and Al-doped tin dioxide nanoparticles have been prepared by co-precipitation method in powdered and sintered pellet form. X-ray diffraction of samples have confirmed that all samples are of SnO2 nanoparticles, polycrystalline in nature with crystallite size 50 nm and lesser. Field emission scanning electron microscopy and energy dispersive spectroscopy have been used to confirm the size and composition of nanoparticles, respectively. Electrical measurements of samples have been carried out in frequency range of 100–100 kHz at intervals of 20 °C in temperature range 40–160 °C. Ac conductivity of sample shows dependency on both frequency and temperature. For undoped samples ac conductivity is governed by multiple hopping processes at room temperature and by correlated barrier hopping model at higher temperatures. However, Al doped SnO2 exhibits overlapping large polaron tunnelling model. From impedance analysis effect of grain boundary due to doping has been studied. It is also found that ac conductivity of samples increases with doping of Al.
- Published
- 2014
25. Graphene–MoS2 hybrid structures for multifunctional photoresponsive memory devices
- Author
-
Srijit Goswami, Gopalakrishnan Ramalingam, T. Phanindra Sai, Arindam Ghosh, Medini Padmanabhan, Srinivasan Raghavan, and Kallol Roy
- Subjects
Materials science ,Graphene ,business.industry ,Band gap ,Materials Research Centre ,Physics ,Relaxation (NMR) ,Biomedical Engineering ,Photodetector ,Bioengineering ,Heterojunction ,Nanotechnology ,Photodetection ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,law.invention ,Responsivity ,Photosensitivity ,law ,Centre for Nano Science and Engineering ,Optoelectronics ,General Materials Science ,Electrical and Electronic Engineering ,business - Abstract
Combining the electronic properties of graphene(1,2) and molybdenum disulphide (MoS2)(3-6) in hybrid heterostructures offers the possibility to create devices with various functionalities. Electronic logic and memory devices have already been constructed from graphene-MoS2 hybrids(7,8), but they do not make use of the photosensitivity of MoS2, which arises from its optical-range bandgap(9). Here, we demonstrate that graphene-on-MoS2 binary heterostructures display remarkable dual optoelectronic functionality, including highly sensitive photodetection and gate-tunable persistent photoconductivity. The responsivity of the hybrids was found to be nearly 1 x 10(10) A W-1 at 130 K and 5 x 10(8) A W-1 at room temperature, making them the most sensitive graphene-based photodetectors. When subjected to time-dependent photoillumination, the hybrids could also function as a rewritable optoelectronic switch or memory, where the persistent state shows almost no relaxation or decay within experimental timescales, indicating near-perfect charge retention. These effects can be quantitatively explained by gate-tunable charge exchange between the graphene and MoS2 layers, and may lead to new graphene-based optoelectronic devices that are naturally scalable for large-area applications at room temperature.
- Published
- 2013
26. Synthesis, structural and optical properties of Al doped SnO2 nanoparticles
- Author
-
Navnita Kumari, S. Tewari, Ayon Bhattacharjee, and Arindam Ghosh
- Subjects
Materials science ,Diffuse reflectance infrared fourier transform ,Band gap ,Tin dioxide ,Doping ,Analytical chemistry ,General Physics and Astronomy ,Nanoparticle ,Condensed Matter::Materials Science ,chemistry.chemical_compound ,chemistry ,Electron diffraction ,Porosity ,Spectroscopy - Abstract
Pure tin dioxide (SnO2) and Al doped SnO2 nanoparticles are prepared by co-precipitation method. Studies on structural and morphological properties are done by X-ray diffraction, field emission scanning electron microscopy and electron diffraction X-ray spectroscopy and optical properties by using UV–Visible spectroscopy in diffuse reflectance spectroscopy mode. Porosity is found to increase with Al doping when compared to pure SnO2. The band gap as well as Urbach energy increases with Al doping. Al doped SnO2 exhibits high porosity.
- Published
- 2013
27. Structural and optical properties of pure and Al doped ZnO nanocrystals
- Author
-
Ayon Bhattacharjee, S. Tewari, Arindam Ghosh, and Navnita Kumari
- Subjects
Absorbance ,Zno nanocrystals ,Materials science ,Dopant ,chemistry ,Wavelength range ,Band gap ,Doping ,Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Zinc ,Crystallite - Abstract
Pure and Al doped zinc oxide (ZnO) were prepared by co-precipitation method. The dopant concentration [Al/Zn in atomic percentage (wt%)] was varied from 0 to 3 wt%. Structural characterisation of the samples performed with XRD and SEM–EDAX confirmed that polycrystalline nature of samples containing ZnO nanoparticles of size in the range of 97–47 nm. UV–Vis studies showed that the absorbance peaks, observed in the wavelength range of 800–250 nm, decreased with the increase in dopant concentration indicating widening of the band gap. The calculations of band gap (analyzed in terms of Burstein–Moss shift) from the reflectance showed an increase from 3.37 to 3.49 eV with increasing Al concentration.
- Published
- 2013
28. Dietary supplementation with N-acetyl cysteine, α-tocopherol and α-lipoic acid reduces the extent of oxidative stress and proinflammatory state in aged rat brain
- Author
-
Mrittika Chattopadhyay, Ishita Guha Thakurta, Arindam Ghosh, and Sasanka Chakrabarti
- Subjects
Mitochondrial ROS ,Aging ,medicine.medical_specialty ,alpha-Tocopherol ,Enzyme-Linked Immunosorbent Assay ,medicine.disease_cause ,Proinflammatory cytokine ,chemistry.chemical_compound ,Internal medicine ,medicine ,Animals ,Tocopherol ,Cell Nucleus ,Inflammation ,chemistry.chemical_classification ,Reactive oxygen species ,NADPH oxidase ,Thioctic Acid ,biology ,NF-kappa B ,Brain ,Acetylcysteine ,Mitochondria ,Rats ,Oxidative Stress ,Lipoic acid ,Endocrinology ,Biochemistry ,chemistry ,Dietary Supplements ,biology.protein ,Cytokines ,Geriatrics and Gerontology ,Reactive Oxygen Species ,Gerontology ,Oxidative stress - Abstract
The present study has attempted to understand how oxidative stress contributes to the development of proinflammatory state in the brain during aging. Three groups of rats have been used in this study: young (4-6 months, Group I), aged (22-24 months, Group II) and aged with dietary antioxidant supplementation (Group III). The antioxidants were given daily from 18 months onwards in the form of a combination of N-acetyl cysteine (50 mg/100 g body weight), α-lipoic acid (3 mg/100 g body weight), and α-tocopherol (1.5 mg/100 g body weight) till the animals were used for the experiments between 22 and 24 months. Several measurements have been made to evaluate the ROS (reactive oxygen species) production rate, the levels of proinflammatory cytokines (IL-1β, IL-6 and TNF-α) and the activation status of NF-κβ (p65 subunit) in brain of the three groups of rats under the study. Our results reveal that brain aging is accompanied with a significant increase in NADPH oxidase activity and mitochondrial ROS production, a distinct elevation of IL-1β, IL-6 and TNF-α levels along with increased nuclear translocation of NF-κβ (p65 subunit) and all these phenomena are partially but significantly prevented by the long-term dietary antioxidant treatment. The results imply that chronic dietary antioxidants by preventing oxidative stress and proinflammatory state may produce beneficial effects against multiple age-related deficits of the brain.
- Published
- 2012
29. Tensile Deformation of a Nickel-base Alloy at Elevated Temperatures
- Author
-
Anand Venkatesh, Vikram Marthandam, Arindam Ghosh, and Ajit K. Roy
- Subjects
Materials science ,Mechanical Engineering ,Metallurgy ,Work hardening ,Strain hardening exponent ,Waspaloy ,Brittleness ,Mechanics of Materials ,Ultimate tensile strength ,General Materials Science ,Composite material ,Deformation (engineering) ,Dynamic strain aging ,Tensile testing - Abstract
The results of tensile testing involving Waspaloy indicate that the failure strain was gradually reduced at temperatures ranging between ambient and 300 °C. Further, serrations were observed in the engineering stress versus strain diagrams in the temperature range of 300-600 °C. The reduced failure strain and the formation of serrations in these temperature regimes could be the result of dynamic strain aging of this alloy. The extent of work hardening due to plastic deformation was reduced at temperatures above 300 °C. A combination of ductile and intergranular brittle failures was seen at temperatures above 600 °C. γ′ was detected at all tested temperatures.
- Published
- 2008
30. String Non(anti)commutativity for Neveu-Schwarz Boundary Conditions
- Author
-
Arindam Ghosh Hazra, Saurav Samanta, Chandrasekhar Chatterjee, and Sunandan Gangopadhyay
- Subjects
High Energy Physics - Theory ,Physics ,Physics and Astronomy (miscellaneous) ,Constraint algebra ,General Mathematics ,FOS: Physical sciences ,Superstring theory ,Field (mathematics) ,String (physics) ,High Energy Physics::Theory ,symbols.namesake ,High Energy Physics - Theory (hep-th) ,Dirichlet boundary condition ,Antisymmetric tensor ,symbols ,Boundary value problem ,Commutative property ,Mathematical physics - Abstract
The appearance of non(anti)commutativity in superstring theory, satisfying the Neveu-Schwarz boundary conditions is discussed in this paper. Both an open free superstring and also one moving in a background antisymmetric tensor field are analyzed to illustrate the point that string non(anti)commutativity is a consequence of the nontrivial boundary conditions. The method used here is quite different from several other approaches where boundary conditions were treated as constraints. An interesting observation of this study is that, one requires that the bosonic sector satisfies Dirichlet boundary conditions at one end and Neumann at the other in the case of the bosonic variables $X^{\mu}$ being antiperiodic. The non(anti)commutative structures derived in this paper also leads to the closure of the super constraint algebra which is essential for the internal consistency of our analysis., Comment: new references added, original article appeared in Int.J.Theor.Phys
- Published
- 2008
31. The possibility of an intrinsic spin lattice in high-mobility semiconductor heterostructures
- Author
-
Arindam Ghosh, Christoph Siegert, David A. Ritchie, Michael Pepper, and Ian Farrer
- Subjects
Physics ,Condensed Matter::Materials Science ,Spin lattice ,Condensed matter physics ,Condensed Matter::Other ,High Energy Physics::Lattice ,General Physics and Astronomy ,Condensed Matter::Strongly Correlated Electrons ,Heterojunction ,Metal–insulator transition ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Semiconductor heterostructures - Abstract
The possibility of an intrinsic spin lattice in high-mobility semiconductor heterostructures
- Published
- 2007
32. Microstructure, properties, and age hardening behavior of a thermomechanically processed ultralow-carbon Cu-bearing high-strength steel
- Author
-
Barada Kanta Mishra, S. Chatterjee, Samar K. Das, and Arindam Ghosh
- Subjects
Quenching ,Precipitation hardening ,Materials science ,Differential scanning calorimetry ,Mechanics of Materials ,Martensite ,Metallurgy ,Metals and Alloys ,Thermomechanical processing ,Particle size ,Microstructure ,Condensed Matter Physics ,Carbide - Abstract
An ultralow-carbon steel alloyed with Ni, Mn, Mo, and Cu and microalloyed with Nb and Ti was subjected to a three-stage controlled rolling operation followed by water quenching. The effect of thermomechanical processing on the microstructure, mechanical properties, and age-hardening behavior of the steel was evaluated. The precipitation behavior of Cu at different aging temperatures was studied by transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The high strength values obtained in the present steel are due to the fine-lath martensite structure along with tiny precipitates of microalloying carbide and carbonitride of Ti and Nb at all finish rolling temperatures (FRTs). The increased strength value at the lower FRT is due to the finer lath width and packet size of martensite. The large TiN particles and the coarse martensite-austenite (MA) constituents impaired the impact-toughness value of the steel at subambient temperature. On aging at different temperatures, a wide variation in structure and properties has been obtained. At low aging temperatures, coherent Cu particles form and a peak strength is obtained due to the formation of fine e-Cu precipitates. On increasing aging temperatures, the Cu particle size increases, with a simultaneous decrease in dislocation density in the matrix resulting in a continuous decrease in strength.
- Published
- 2005
33. Optoelectronic properties of graphene-MoS2 hybrid
- Author
-
Srinivasan Raghavan, Srijit Goswami, Sanjeev Kaushal, Kallol Roy, Arindam Ghosh, Gopalakrishnan Ramalingam, Medini Padmanabhan, and T. Phanindra Sai
- Subjects
Materials science ,business.industry ,Graphene ,law ,Photoconductivity ,White light ,Optoelectronics ,Chemical vapor deposition ,business ,Gate voltage ,law.invention - Abstract
Ultra-thin flakes of layered materials have recently been attracting widespread research interest due to their exotic properties. In this work, we study the optoelectronic response of a hybrid of two such materials – graphene and MoS2. Our devices consist of mechanically exfoliated graphene flakes transferred on top of similarly exfoliated MoS2. The electrical response of the hybrid is studied in the presence of white light. We show that the four-point resistance of graphene is modulated in the presence of light. This effect is observed to be a strong function of gate voltage. We have also extended our studies to CVD (chemical vapor deposition) - grown graphene transferred onto MoS2 which show qualitatively similar features, thereby attesting to the scalability of the device architecture.
- Published
- 2013
34. String Non(anti)commutativity for Neveu-Schwarz Boundary Conditions
- Author
-
Chatterjee, Chandrasekhar, primary, Gangopadhyay, Sunandan, additional, Hazra, Arindam Ghosh, additional, and Samanta, Saurav, additional
- Published
- 2008
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