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      • KCI등재SCOPUS

        ION IRRADLATION STUDIES OC CARGON FILMS PREPARED BY PLASMA ASSISTED CVD METHOD

        Bhattacharyya, Bhattacharyya, Somnath-,Sayeed, Ahmed,Kanjilal, Kanjilal, D.,Subramanyam, S.V 한국재료학회 1995 Fabrication and Characterization of Advanced Mater Vol.1 No.3

        Amorphous hydrogeneted carbon films were prepared by plasma assisted cvd metnod and their dc conductivity as studied as a function of temperature in the range of 300K to 10K. Films were then subjected to high energy(170MeV)$I^{+13}$ ion irradiation. After irradiation an marked change was observed in the conductivity and its temperature dependenc. The conductivity decreased by 2 to 3 orders of magnitude, room temperature activation energy increased and a gap appeared in the electronic structure. Photo-emission spectropic study on the material show a decrease in the $\pi$ states of the electronic density of states spectrum from UPS and a noticible change in the Cls peak shape in XPS.

      • KCI등재

        Damage detection of multi-storeyed shear structure using sparse and noisy modal data

        S.K. Panigrahi,S. Chakraverty,S.K. Bhattacharyya 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.15 No.5

        In the present paper, a method for identifying damage in a multi storeyed shear building structure is presented using minimum number of modal parameters of the structure. A damage at any level of the structure may lead to a major failure if the damage is not attended at appropriate time. Hence an early detection of damage is essential. The proposed identification methodology requires experimentally determined sparse modal data of any particular mode as input to detect the location and extent of damage in the structure. Here, the first natural frequency and corresponding partial mode shape values are used as input to the model and results are compared by changing the sensor placement locations at different floors to conclude the best location of sensors for accurate damage identification. Initially experimental data are simulated numerically by solving eigen value problem of the damaged structure with inclusion of random noise on the vibration characteristics. Reliability of the procedure has been demonstrated through a few examples of multi storeyed shear structure with different damage scenarios and various noise levels. Validation of the methodology has also been done using dynamic data obtained through experiment conducted on a laboratory scale steel structure.

      • KCI등재후보

        Repeated dose toxicity of alfa-cypermethrin in rats

        S Manna,D Bhattacharyya,TK Mandal,S Das 대한수의학회 2004 Journal of Veterinary Science Vol.5 No.3

        The present study was performed to investigate the subacute effect of α-cypermethrin (α-CP) in rats. Alfacypermethrin a synthetic pyrethroid insecticide, dissolved in dimethyl sulfoxide (DMSO) and oral LD50 was investigated after administering orally different doses in rats and was determined as 145 mg/kg. Other groups of rats were given repeated daily oral dose (1/10 LD50) of α-CP for 30 days. The animals were sacrificed on 31st day. Activities of various enzymes, cytochrome P450 and b5 contents in liver, hepatic antioxidant status, tissue residue concentration, haemogram and pathological changes were studied. It increased the serum aminotransaminases (AST,ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) activities and blood glucose level significantly. α-CP decreased RBC count, PCV and Hb level significantly. It significantly decreased cytochrome P450 in liver. Residues were present in different tissues. It increased malondialdehyde (MDA) level, while decreased the activities of catalase (CAT), superoxide dismutase (SOD) and glycogen level in liver significantly. Mild to moderate histological alterations were observed in lungs, liver, stomach, kidneys, testes and cerebellum. So repeated daily oral doses of α-CP at 1/10LD50 altered the biochemical parameters, decreased cytochrome P450 content, antioxidant status, which correlated with histopathological changes of tissues.

      • KCI등재후보

        Modulation of 3D Bioprintability in Polysaccharide Bioink by Bioglass Nanoparticles and Multiple Metal Ions for Tissue Engineering

        Bhattacharyya Amitava,Khatun Mst Rita,Narmatha S.,Nagarajan R.,Noh Insup 한국조직공학과 재생의학회 2024 조직공학과 재생의학 Vol.21 No.2

        Background: Bioglasses are used in applications related to bone rehabilitation and repair. The mechanical and bioactive properties of polysaccharides like alginate and agarose can be modulated or improved using bioglass nanoparticles. Further essential metal ions used as crosslinker have the potential to supplement cultured cells for better growth and proliferation. Method: In this study, the alginate bioink is modulated for fabrication of tissue engineering scaffolds by extrusion-based 3D bioprinting using agarose, bioglass nanoparticles and combination of essential trace elements such as iron, zinc, and copper. Homogeneous bioink was obtained by in situ mixing and bioprinting of its components with twin screw extruder (TSE) based 3D bioprinting, and then distribution of metal ions was induced through post-printing diffusion of metal ions in the printed scaffolds. The mechanical and 3d bioprinting properties, microscopic structure, biocompatibility of the crosslinked alginate/agarose hydrogels were analyzed for different concentrations of bioglass. The adipose derived mesenchymal stem cells (ADMSC) and osteoblast cells (MC3T3) were used to evaluate this hydrogel’s biological performances. Results: The porosity of hydrogels significantly improves with the incorporation of the bioglass. More bioglass concentration results in improved mechanical (compressive, dynamic, and cyclic) and 3D bioprinting properties. Cell growth and extracellular matrix are also enhanced with bioglass concentration. Conclusion: For bioprinting of the bioinks, the advanced TSE head was attached to 3D bioprinter and in situ fabrication of cell encapsulated scaffold was obtained with optimized composition considering minimal effects on cell damage. Fabricated bioinks demonstrate a biocompatible and noncytotoxic scaffold for culturing MC3T3 and ADMSC, while bioglass controls the cellular behaviors such as cell growth and extracellular matrix formation. Background: Bioglasses are used in applications related to bone rehabilitation and repair. The mechanical and bioactive properties of polysaccharides like alginate and agarose can be modulated or improved using bioglass nanoparticles. Further essential metal ions used as crosslinker have the potential to supplement cultured cells for better growth and proliferation. Method: In this study, the alginate bioink is modulated for fabrication of tissue engineering scaffolds by extrusion-based 3D bioprinting using agarose, bioglass nanoparticles and combination of essential trace elements such as iron, zinc, and copper. Homogeneous bioink was obtained by in situ mixing and bioprinting of its components with twin screw extruder (TSE) based 3D bioprinting, and then distribution of metal ions was induced through post-printing diffusion of metal ions in the printed scaffolds. The mechanical and 3d bioprinting properties, microscopic structure, biocompatibility of the crosslinked alginate/agarose hydrogels were analyzed for different concentrations of bioglass. The adipose derived mesenchymal stem cells (ADMSC) and osteoblast cells (MC3T3) were used to evaluate this hydrogel’s biological performances. Results: The porosity of hydrogels significantly improves with the incorporation of the bioglass. More bioglass concentration results in improved mechanical (compressive, dynamic, and cyclic) and 3D bioprinting properties. Cell growth and extracellular matrix are also enhanced with bioglass concentration. Conclusion: For bioprinting of the bioinks, the advanced TSE head was attached to 3D bioprinter and in situ fabrication of cell encapsulated scaffold was obtained with optimized composition considering minimal effects on cell damage. Fabricated bioinks demonstrate a biocompatible and noncytotoxic scaffold for culturing MC3T3 and ADMSC, while bioglass controls the cellular behaviors such as cell growth and extracellular matrix formation.

      • KCI등재
      • Fuzzy event tree analysis for quantified risk assessment due to oil and gas leakage in offshore installations

        Cheliyan, A.S.,Bhattacharyya, S.K. Techno-Press 2018 Ocean systems engineering Vol.8 No.1

        Accidental oil and gas leak is a critical concern for the offshore industry because it can lead to severe consequences and as a result, it is imperative to evaluate the probabilities of occurrence of the consequences of the leakage in order to assess the risk. Event Tree Analysis (ETA) is a technique to identify the consequences that can result from the occurrence of a hazardous event. The probability of occurrence of the consequences is evaluated by the ETA, based on the failure probabilities of the sequential events. Conventional ETA deals with events with crisp failure probabilities. In offshore applications, it is often difficult to arrive at a single probability measure due to lack of data or imprecision in data. In such a scenario, fuzzy set theory can be applied to handle imprecision and data uncertainty. This paper presents fuzzy ETA (FETA) methodology to compute the probability of the outcomes initiated due to oil/gas leak in an actual offshore-onshore installation. Post FETA, sensitivity analysis by Fuzzy Weighted Index (FWI) method is performed to find the event that has the maximum contribution to the severe sequences. It is found that events of 'ignition', spreading of fire to 'equipment' and 'other areas' are the highest contributors to the severe consequences, followed by failure of 'leak detection' and 'fire detection' and 'fire water not being effective'. It is also found that the frequency of severe consequences that are catastrophic in nature obtained by ETA is one order less than that obtained by FETA, thereby implying that in ETA, the uncertainty does not propagate through the event tree. The ranking of severe sequences based on their probability, however, are identical in both ETA and FETA.

      • Field-induced stretching and dynamic reorientation of functionalized multiwalled carbon nanotube aggregates in nematic liquid crystals

        Tie, W.,Bhattacharyya, S.S.,Zhang, Y.,Zheng, Z.,Lee, T.H.,Lee, S.W.,Kim, T.H.,Lee, Y.H.,Lee, S.H. Pergamon Press ; Elsevier Science Ltd 2016 Carbon Vol.96 No.-

        <P>Multiwalled carbon nanotubes (MWCNTs) exhibited distinct electrical stretching behavior in nematic liquid crystals (NLC) depending on nanotube surface state. We found that two different samples prepared by chemical functionalization (f-CNT) and physical grinding (g-CNT) revealed distinct field dependence from each other. The threshold stretching field was lower in the f-CNT aggregates than in g-CNT aggregates. This was attributed to polar functionality induced weakened van der Waals interaction in f-CNTs, which was confirmed in infrared (IR) and Raman spectroscopy. Dynamic reorientation of f-CNTs was observed under polarized optical microscopy where f-CNTs were found to follow orientation of NLC director. Uniformly aligned f-CNTs also exhibited selective light absorption in sufficiently long transient field off-state which could find potential applications in memory and modulator devices as well as the versatile functional composites. (C) 2015 Elsevier Ltd. All rights reserved.</P>

      • User Behaviour Profiling in Cloud using One Class SVM : A Review

        Vijaya Lakshmi Paruchuri,S. Suresh Babu,P S V S Sridhar,Debnath Bhattacharyya,Hye-Jin Kim 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.9

        Distributed computing guarantees to on a very basic level change the way we utilize PCs and get to and store our own specific and business data. With these new registering and correspondences models develop new data security challenges. Existing information security structures, for instance, encryption have fizzled in imagining information theft strikes, particularly those executed by an insider to the cloud supplier. We propose a substitute methodology for securing information in the cloud utilizing adversarial mimic improvement. We screen data access in the cloud and perceive unpredictable data access outlines. Right when unapproved access is suspected and after that confirmed using test questions, we dispatch a disinformation strike by giving back a considerable measure of fake information to the attacker. This secures against the misuse of the customer's real data. Trials coordinated in a neighbor-hood archive setting give confirmation this technique may give unprecedented levels of customer data security in a Cloud space.

      • Synthesis of absolutely stabilising controllers

        Malik, W.A.,Kang, S.,Darbha, S.,Bhattacharyya, S.P. IET 2008 IET control theory & applications Vol.2 No.10

        <P>The synthesis of fixed order controllers for nonlinear systems with sector bounded nonlinearities is considered. The authors constructed an inner and outer approximation of the set of absolutely stabilising linear controllers by casting the closed loop system as a Lure-Postnikov system. The inner approximation is based on the well-known sufficient conditions that require strict positive realness (SPR) of open loop transfer function (possibly with some multipliers) and a characterisation of SPR transfer functions that require a family of complex polynomials to be Hurwitz. The outer approximation is based on the condition that the open loop transfer function must have infinite gain margin, which translates to a family of real polynomials being Hurwitz. The authors illustrate the proposed methodology through the construction of an inner and outer approximation of absolutely stabilising controllers for a mechanical system.</P>

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