Faculty Publications

Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736

Publications by NITK Faculty

Browse

Has files: NoSubject: search.filters.subject.Shielding

Search Results

Now showing 1 - 6 of 6
  • No Thumbnail Available
    Item
    Gamma radiation shielding characteristics of concrete mixes-the state of art
    (2013) Santhoshkumar, M.; Narasimhan, M.C.; Karkera, B.
    In this paper, initially the interaction of gamma radiation with materials in general and concrete in particular are discussed. The state-of-art attempts made in different parts of the world, in improving the gamma radiation shielding properties by incorporating alternate/additional ingredients in concrete mixes are discussed. Such incorporation may be in terms of changes in any of the binder, coarse or fine aggregate components of the concrete mixes. The usage of materials such as mineral admixtures, high density solid wastes and fibres is also reported. The possible use of other mineral materials in concrete mixes for enhanced shielding performance against gamma radiation in nuclear installations is brought out. A brief review of the mix design parameters controlling shielding performance of concrete mixes is also cited. An attempt has been made to compare the shielding performances of different concretes by comparing their linear attenuation co-efficient values (μ) reported in the literature. In view of the exponential surge in γ-ray sources in nuclear industry this review is relevant to save the planet earth from an impending global disaster as well as introducing radiation in industries, food preservation, nuclear medicine and many other such applications. © 2013 CAFET-INNOVA TECHNICAL SOCIETY.
  • No Thumbnail Available
    Item
    Effect of mix parameters and hydrogen loading on neutron radiation shielding characteristics of latex modified concrete mixes
    (Elsevier Ltd, 2015) Malkapur, S.M.; Satdive, H.; Narasimhan, M.C.; Karkera, N.B.; Goverdhan, P.; Sathian, V.
    With the tremendous surge in the usage of radioactive materials in industry, education and research, medicine and other fields, it becomes a concern to protect the working personnel and common people around, from hazardous radiation leakages that may seriously affect their health. Among the different types of radiation, gamma and neutron radiations require adequate shielding. There have been several attempts to develop newer concretes and evaluate their neutron radiation shielding characteristics. In the present study, an attempt has been made to study the effect of varying the mix parameters and hence the resulting total hydrogen content on the neutron radiation shielding characteristics of Latex Modified Concrete (LMC) mixes. The experiments are planned in such a way that the hydrogen content of the mixes is varied by controlling the mix parameters i.e., cement content, water/cement ratio and polymer/cement ratio of LMC mixes. The results are statistically analyzed. It is found that definite improvements could be achieved in neutron radiation shielding characteristics of LMC mixes as compared to ordinary concrete, with the increase in hydrogen concentration effected by changes in mix parameters. © 2015 Elsevier Ltd All rights reserved.
  • No Thumbnail Available
    Item
    Neutron radiation shielding properties of polymer incorporated self compacting concrete mixes
    (Elsevier Ltd, 2017) Malkapur, S.M.; Divakar, L.; Narasimhan, M.C.; Karkera, N.B.; Goverdhan, P.; Sathian, V.; Prasad, N.K.
    In this work, the neutron radiation shielding characteristics of a class of novel polymer-incorporated self-compacting concrete (PISCC) mixes are evaluated. Pulverized high density polyethylene (HDPE) material was used, at three different reference volumes, as a partial replacement to river sand in conventional concrete mixes. By such partial replacement of sand with polymer, additional hydrogen contents are incorporated in these concrete mixes and their effect on the neutron radiation shielding properties are studied. It has been observed from the initial set of experiments that there is a definite trend of reductions in the neutron flux and dose transmission factor values in these PISCC mixes vis-à-vis ordinary concrete mix. Also, the fact that quite similar enhanced shielding results are recorded even when reprocessed HDPE material is used in lieu of the virgin HDPE attracts further attention. © 2017 Elsevier Ltd
  • No Thumbnail Available
    Item
    Fresh and hardened properties of polymer incorporated self compacting concrete mixes for neutron radiation shielding
    (Elsevier Ltd, 2017) Malkapur, S.M.; Divakar, L.; Narasimhan, M.C.; Karkera, N.B.; Goverdhan, P.; Sathian, V.; Prasad, N.K.
    Several works in the past have reported that the hydrogen content in the hydrated concrete plays an important role in shielding the neutron radiation; higher the hydrogen content, better is the neutron radiation shielding. In this study, pulverised high density polyethylene (HDPE) material is used as an additional source of hydrogen within concrete to develop a novel class of Polymer-Incorporated Self-Compacting Concrete (PISCC) mixes for enhanced neutron radiation shielding. The HDPE material was incorporated as a partial replacement to river sand. It is found that the PISCC mixes have satisfactory fresh and hardened properties and enhanced neutron radiation shielding properties. © 2017 Elsevier Ltd
  • No Thumbnail Available
    Item
    Incorporation of graphite into iron decorated polypyrrole for dielectric and EMI shielding applications
    (Elsevier Ltd, 2020) Madhusudhan, C.K.; Mahendra, K.; Madhukar, B.S.; Somesh, T.E.; Faisal, M.
    Synthesis of polypyrrole (PPy) / graphite (G) composites via chemical oxidation polymerization method is reported. Synthesized composites were studied for its structural, optical and electrical properties. Structural and morphological studies were performed using powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and the effect of graphite on the properties of PPy is elaborated in detail. Further, the electrical measurements were carried using dielectric analyzer. Dielectric behavior of the composites was also compared with the PPy and graphite and confirmed the dependency of graphite on PPy/graphite nanocomposites. The EMI shielding response of PPy/graphite nanocomposites were measured in the microwave frequency range from 12 to 18 GHz (Ku band), of practical relevance. The observed effective electrical and EMI shielding properties highlights the prospects of multifunctional applications of these PPy/graphite nanocomposites. © 2020 Elsevier B.V.
  • No Thumbnail Available
    Item
    Multifunctional Polypyrrole/Multi-Walled Carbon Nanotube Composite Material: Dielectric, Humidity Sensing and Broadband EMI Shielding Properties
    (Pleiades journals, 2021) Madhusudhan, C.K.; Mahendra, K.; Madhukar, B.S.; Somesh, T.E.; Faisal, M.
    Abstract: Conducting polymer composites with suitable combination of two components in nanoscale are expected to facilitate wider applications of composites. In this study, polypyrrole (PPy)/multiwalled carbon nanotube (MWCNT) nanocomposites prepared by in situ chemical oxidative polymerization were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and UV–Vis spectroscopy. The electrical and dielectric properties were investigated using complex impedance technique. Complex dielectric permittivity, complex electric modulus and complex impedance variations were studied in the frequency range of 10 Hz–1 MHz. The dielectric attributes and conductivity data of different nanocomposites analyzed as a function of frequency revealed that the incorporation of MWCNT phase into polypyrrole matrix affects the electrical and dielectric properties of the composites. Humidity sensor measurements show that PPy/MWCNT can be effectively optimized as candidate for humidity detection. The nanocomposites were also studied for broadband EMI shielding applications by characterizing the materials in the 12?18 GHz (Ku band) to understand the shielding properties. The absorption dominant shielding effectiveness (SE) observed in the range of ?13 to ?15 dB was stable with visible variation with varying concentration of MWCNT in PPy. The experimental results of dielectric characterization, humidity sensing and EMI shielding response reveal that PPy/MWCNT composite can be suitable multifunctional material for various applications. © 2021, Pleiades Publishing, Ltd.