Interfacial Properties of Metallized Alumina Ceramics

Sumana Ghosh,Kalyan Sundar Pal,Nandadulal Dandapat,Someswar Datta,Debabrata Basu 대한금속·재료학회 2012 METALS AND MATERIALS International Vol.18 No.4

An alumina ceramic material (purity-96%) was metallized by the conventional molybdenum-manganese (Mo-Mn) process in which an alumina substrate was coated with Mo-Mn paste and subsequently heat treated at 1400 °C for 10 min. During the entire process a moist H2 and N2 gas mixture (dew point-20 °C)with 3:1 ratio was passed continuously through the furnace. X-ray diffraction analysis of the metallized alumina substrate identified only molybdenum phase at the surface of the metallizing layer. The microstructural observations of the metallized alumina substrate were made by scanning electron microscopy. Energy dispersive X-ray analysis showed the elemental compositions along the cross-sectional region of the metallized alumina substrate. The adhesion of the metallic coatings on the alumina substrates was evaluated qualitatively by a scratch testing technique and quantitatively by an adhesion tester. Nanohardness measurements showed gradual change in the nanohardness values across the metallized alumina substrate.

The Influence of Customer Trust and Loyalty on Repurchase Intention of Domestic Tourism: A Case Study in Thailand During COVID-19 Crisis

Sumana LAPAROJKIT,Muttanachai SUTTIPUN 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.5

The study aimed to investigate the level of customer trust, loyalty, and re-purchase intention of coastal tourism in Thailand during the COVID-19 crisis; to test the different levels of customer trust, loyalty, and re-purchase intention by local tourists between East-side and West-side coasts of Thailand; and to examine the influence of customer trust and loyalty on re-purchase intention in coastal tourism. Using multistage sampling, this study sampled 487 Thai local tourists who had experienced coastal tourism in Thailand during the COVID-19 crisis. A questionnaire, descriptive analysis, independent sample t-test, correlation matrix, and multiple regression analysis were used to collect and analyze the data. All customer trust, loyalty, and re-purchase intentions in coastal tourism by local tourists were at a high level. There were significantly different levels of customer trust, loyalty, and re-purchase intentions by local Thai tourists between the East-side and West-side coasts of Thailand. Moreover, the study found that there was a significant positive influence of customer trust and loyalty on re-purchase intentions in coastal tourism by local tourists in Thailand during the COVID-19 crisis. This study indicates that Thai tourism industry still must develop and improve its local customer loyalty and trust because these positively influence customer re-purchase intentions.

Development of A Small Vocabulary Database for Bengali Speech Recognition

Sumana Huque,Md. Abdullah Al Asad,Md Rokonuzzaman 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.8

This paper describes a small vocabulary Bengali database development to evaluate the performance of speech recognition algorithms in clean conditions. The database is constructed by Bangla digit sequences (/ak/, /dui/, /tin/, /chaar/, /panch/, /chhoy/, /shaat/, /aat/, /noy/, /zero/, /shunno/) are used. The developed database is consisted of two sets of data which are training and testing datasets. The training dataset contains 3824 utterances of 50 speakers; on the other hand, the testing dataset is subdivided into four groups (clean1, clean2, clean3 and clean4) and contains 1985 utterances of 52 speakers. In both sets of data the speaker’s age ranges from 19 to 25 years. All the recordings have been done in a quiet room but not soundproof with the A4Tech HS-60 headset microphone interfaced to an Intel Dual Core 2.0 GHz CPU. The software used to record and edit the speech file is wave-pad; ver. 3.05.The recognition experiment is presented in this thesis to obtain comparable recognition results for the speaker-independent recognition of connected sequences of Bangla digit. As the research results has proved that the words accuracy is average 98%.

Detection of Escherichia coli in Food Samples by Magnetosome-based Biosensor

Sumana Sannigrahi,Shiva Kumar A,J. Mathiyarasu,K. Suthindhiran 한국생물공학회 2023 Biotechnology and Bioprocess Engineering Vol.28 No.1

The rising cases of food poisoning and traveler’s diarrhea through Escherichia coli infection are a global concern. Magnetosome is biogenic magnetic nanoparticles extracted from magnetotactic bacteria and magnetosomebased biosensors offer simple and rapid detection of microbial pathogens. The current study demonstrates the application of a magnetosome-antibody complex-based biosensor for the detection of antigenic O-polysaccharide and E. coli from contaminated food samples. The magnetosome (1, 2 mg/mL)-antibody (0.8-200 μg/mL) complex was initially coupled with lipopolysaccharide (5 μg/mL) through antibody-antigen interaction. The magnetosome (1, 2 mg/mL)-antibody (0.8-200 μg/mL)-lipopolysaccharide (5 μg/mL) complexes were collected via external magnet and confirmed through spectroscopy studies. The magnetosome (1, 2 mg/mL)-antibody (0.8-200 μg/mL) complexes were applied to different concentration of lipopolysaccharide (0.01-50 μg/mL). The concentrated magnetosome (2 mg/ mL)-antibody (1.6 μg/mL) complex and lipopolysaccharide (0.1 μg/mL) were established in ELISA. Further, the magnetosome-antibody complex was applied on a screenprinted carbon electrode and stabilized through an external magnet. The least concentration of lipopolysaccharide (0.5 μg/mL) was determined in impedance. Further, the magnetosome-based biosensor was applied to various contaminated food samples- milk, water, and pineapple juice and the extracted lipopolysaccharide were selectively detected. The biosensor did not display any cross-reactivity and therefore exhibits specificity. The active E. coli (101 CFU/mL) from milk and water samples were also rapidly detected within 30 min by the developed biosensor. Furthermore, the field emission scanning electron microscope images confirmed the efficient detection of E. coli from the food sample.

A Multi-Level Integrator with Programming Based Boosting for Person Authentication Using Different Biometrics

( Sumana Kundu ),( Goutam Sarker ) 한국정보처리학회 2018 Journal of information processing systems Vol.14 No.5

A multiple classification system based on a new boosting technique has been approached utilizing different biometric traits, that is, color face, iris and eye along with fingerprints of right and left hands, handwriting, palm-print, gait (silhouettes) and wrist-vein for person authentication. The images of different biometric traits were taken from different standard databases such as FEI, UTIRIS, CASIA, IAM and CIE. This system is comprised of three different super-classifiers to individually perform person identification. The individual classifiers corresponding to each super-classifier in their turn identify different biometric features and their conclusions are integrated together in their respective super-classifiers. The decisions from individual superclassifiers are integrated together through a mega-super-classifier to perform the final conclusion using programming based boosting. The mega-super-classifier system using different super-classifiers in a compact form is more reliable than single classifier or even single super-classifier system. The system has been evaluated with accuracy, precision, recall and F-score metrics through holdout method and confusion matrix for each of the single classifiers, super-classifiers and finally the mega-super-classifier. The different performance evaluations are appreciable. Also the learning and the recognition time is fairly reasonable. Thereby making the system is efficient and effective.

Valuations on Ternary Semirings

Pal, Sumana,Sircar, Jayasri,Mondal, Pinki Department of Mathematics 2022 Kyungpook mathematical journal Vol.62 No.1

In the present study, we introduce a valuation of ternary semiring on an ordered abelian group. Motivated by the construction of valuation rings, we study some properties of ideals in ternary semiring arising in connection with the valuation map. We also explore ternary valuation semirings for a noncommuative ternary division semiring. We further consider the notion of convexity in a ternary semiring and how it is reflected in the valuation map.

A Multi-Level Integrator with Programming Based Boosting for Person Authentication Using Different Biometrics

Kundu, Sumana,Sarker, Goutam Korea Information Processing Society 2018 Journal of information processing systems Vol.14 No.5

A multiple classification system based on a new boosting technique has been approached utilizing different biometric traits, that is, color face, iris and eye along with fingerprints of right and left hands, handwriting, palm-print, gait (silhouettes) and wrist-vein for person authentication. The images of different biometric traits were taken from different standard databases such as FEI, UTIRIS, CASIA, IAM and CIE. This system is comprised of three different super-classifiers to individually perform person identification. The individual classifiers corresponding to each super-classifier in their turn identify different biometric features and their conclusions are integrated together in their respective super-classifiers. The decisions from individual super-classifiers are integrated together through a mega-super-classifier to perform the final conclusion using programming based boosting. The mega-super-classifier system using different super-classifiers in a compact form is more reliable than single classifier or even single super-classifier system. The system has been evaluated with accuracy, precision, recall and F-score metrics through holdout method and confusion matrix for each of the single classifiers, super-classifiers and finally the mega-super-classifier. The different performance evaluations are appreciable. Also the learning and the recognition time is fairly reasonable. Thereby making the system is efficient and effective.

Electro-optic properties of aligned polysiloxane dispersed ferroelectric liquid crystal composite thin films

G. Sumana,K. K. Raina 한국물리학회 2005 Current Applied Physics Vol.5 No.3

Thin polymer dispersed ferroelectric liquid crystal (PDFLC) composite lms were prepared using polydimethyl siloxanes ofdierent viscosity grades and ferroelectric liquid crystal mixture (ZLI-3654) using solvent induced phase separation (SIPS) andpolymer induced phase separation (PIPS) techniques simultaneously.The electro-optic properties of these lms in aligned and unaligned congurations were measured. A comparison indicates thatthe performance of aligned PDFLCs is better over that of the unaligned lms. Structureproperty correlation in these materials havebeen studied and explained on the basis of the viscosity of the polysiloxane matrix. These materials are found to be promising forexible liquid crystal display devices..

Numerical solution of time-delayed Burgers’ equations using Haar wavelets

K.P. SUMANA,L.N. ACHALA,VISHNU NARAYAN MISHRA 장전수학회 2019 Advanced Studies in Contemporary Mathematics Vol.29 No.3

In this paper, an ecient numerical scheme based on uni- form Haar wavelets is used to solve the time-delayed Burgers' equations. The quasilinearization technique is used to conveniently handle the non- linear terms in the time-delayed Burgers' equations. The basic idea of Haar wavelet collocation method is to convert the partial dierential equation into a system of algebraic equations that involves a nite num- ber of variables. The solutions obtained by Haar wavelet collocation method are compared with the exact solutions and are found to be in good agreement. The error analysis of the Haar wavelet method shows that the accuracy of the method improves as the level of resolution of the Haar wavelet is increased.

NUMERICAL SIMULATION OF ELLIPTIC PARTIAL DIFFERENTIAL EQUATIONS USING 3-SCALE HAAR WAVELETS

K.P. SUMANA,L.N. ACHALA,VISHNU NARAYAN MISHRA 장전수학회 2021 Advanced Studies in Contemporary Mathematics Vol.31 No.3

Elliptic partial differential equations (PDEs) arise in the mathematical modelling of many physical phenomena in science and engineering. In this paper, we obtain the numerical solution of Laplace and Poisson equations using two-dimensional 3-scale Haar wavelets. The elliptic PDEs are converted into a system of algebraic equations that involve a finite number of variables. The numerical results are compared with the exact solution to prove the accuracy of the Haar wavelet method. The error analysis of the 3-scale Haar wavelet method proves that the solution improves with the increase in the levels of resolution of the wavelet.