Showing papers by "Tushar Kanti Bera published in 2015"
16 Mar 2015
TL;DR: In this paper, a small amount of alternating current is injected to the banana attached to an array of Ag/AgCl electrodes and the surface potentials are measured using Agilent 4294A impedance Analyzer.
Abstract: Electrical Impedance of biological tissues changes with the change in tissue anatomy and tissue physiology. Electrical Impedance Spectroscopy (EIS) has been studied to characterize the biological objects like fruits and vegetables for assessing their freshness. In this direction, the EIS studies have been conducted as a non-destructive investigation evaluation method to study the electrical impedance variations in banana ripening. The aim of the work is to correlate the impedance variation with the ripening process in banana. A small amount of alternating current is injected to the banana attached to an array of Ag/AgCl electrodes and the surface potentials are measured using Agilent 4294A impedance Analyzer. The banana impedance and phase angles are measured from 50 Hz and 1 MHz. The results demonstrate that the electrical impedance of banana varies significantly during its ripening. From the experimental studies, it is observed that the impedance, real part and imaginary part of the impedance all are increased with the progresses in the banana ripening process.
32 citations
TL;DR: In this paper, an alternative processing technique based on the use of pulsed laser irradiation is proposed to identify the processing parameters that result in selective removal of the electrically insulating resin with minimum surface fiber damage, and a quantitative analysis of the electrical contact resistance is presented and the results are compared with those obtained using sanding.
22 citations
01 Jan 2015
TL;DR: This chapter will present the review of the studies on the noninvasive electromagnetic methods for brain monitoring, diagnosis and treatment, and discuss about the present scenario of the conventional brain monitoring methods with their merits and demerits.
Abstract: Human brain is a large, complex and most important organ in its nervous system. The brain works as a central processing unit (CPU) of the human body and performs, coordinate, control and regulate an incredible number of tasks to keep the human body healthy and alive. Though the brain is highly protected inside the rigid skull, meninges and cerebral spinal fluid (CSF), the human brain is still sometimes gets injured, damaged and gets several number of diseases. Therefore the study of brain is important and very essential for diagnose and treatment of the diseases like stroke, brain tumors, traumatic brain injury, encephalitis, meningitis, Parkinson’s disease, intracerebral hemorrhage, brain aneurysm, multiple sclerosis, hydrocephalus etc. As the electromagnetic brain imaging methods have drawn a lot of attentions of the medical doctors, clinicians and biomedical researchers for their unique advantages. This chapter will present the review of the studies on the noninvasive electromagnetic methods for brain monitoring, diagnosis and treatment. The chapter will try to present the detail technical aspects of different electromagnetic brain monitoring modalities (EBMM), their applications and challenges. The chapter will start by introducing to the human brain and its diseases followed by a discussion on the history and the developments of the brain monitoring techniques. It will discuss about the present scenario of the conventional brain monitoring methods with their merits and demerits. The chapter will explain the electromagnetic brain monitoring techniques in detail such as Electroencephalography (EEG), Magnetoencephalography (MEG), Electrocorticography (ECoG), electroneurogram (ENG), electrical impedance tomography (EIT), Quantitative susceptibility mapping (QSM) and other advanced brain monitoring modalities. The chapter will discuss about their working principles, applications, advantages, disadvantages, present scenario. The chapter will summarize the studies on the electromagnetic methods for brain monitoring and it will conclude with a discussion on the present challenges and future trends.
18 citations
17 Feb 2015
TL;DR: In this paper, a gold sensor array with high geometric precision was developed for EIT phantoms to improve the resistivity image quality, which reduced the SNR of boundary potential data due to their design and development errors.
Abstract: Surface electrodes in Electrical Impedance Tomography (EIT) phantoms usually reduce the SNR of the boundary potential data due to their design and development errors. A novel gold sensors array with high geometric precision is developed for EIT phantoms to improve the resistivity image quality. Gold thin films are deposited on a flexible FR4 sheet using electro-deposition process to make a sixteen electrode array with electrodes of identical geometry. A real tissue gold electrode phantom is developed with chicken tissue paste and the fat cylinders as the inhomogeneity. Boundary data are collected using a USB based high speed data acquisition system in a LabVIEW platform for different inhomogeneity positions. Resistivity images are reconstructed using EIDORS and compared with identical stainless steel electrode systems. Image contrast parameters are calculated from the resistivity matrix and the reconstructed images are evaluated for both the phantoms. Image contrast and image resolution of resistivity images are improved with gold electrode array.
7 citations
16 Mar 2015
TL;DR: In this article, the thin domain wide electrode (TDWE) phantoms are proposed for electrical impedance tomography (EIT) to reduce the 3D error by maintaining the required EEGR.
Abstract: Electrical Impedance Tomography (EIT) is a nonlinear ill posed inverse problem which is very prone to modeling errors. 2D-EIT reconstructs the spatial distribution of the object impedance profile comparing the measurements of boundary voltage data collected from a 3D object with the calculated data generated from an absolute 2D domain in computer. As the 2D-EIT assumes current conduction in two dimensional plane of EIT electrode array, the 2D EIT systems working with a practical 3D phantom produce some error and hence the forward modeling should be modified accordingly. On the other hand, the 3D error can be reduced by using long electrodes but in long electrode system, the electrode to electrode gap (EEGR) ratio required to be maintained to attain a good sensitivity is found difficult. In this direction the thin domain wide electrode (TDWE) phantoms are proposed for electrical impedance tomography (EIT) to reduce the 3D error by maintaining the required EEGR. A LabVIEW based multifrequency EIT instrumentation has been developed and a number of TDWE phantoms with different inhomogeneity configurations have been studied. Absolute impedance images reconstructed in EIDORS, demonstrate that developed TDWE phantom improves image quality by reducing the 3D error.
4 citations