Browsing by Author "Karthika S"

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CERAMIZATION OF ABO GLASSES UNDER THE INFLUENCE OF O7+ ION IRRADIATION (Article)
(Elsevier Ltd, 2025-02) Karthika S; Asokan K; Marimuthu K; Meena, Ramcharan; Sundari, S Shanmuga
Alkali borate (ABO) glasses of the composition 15A2O-85B2O3 where A = Li (lithium), Na (sodium) and K (potassium) are prepared using the thermal melt quenching technique. Pure analytical grades of boric acid (H3BO3), lithium carbonate (Li2CO3), sodium carbonate (Na2CO3) and potassium carbonate (K2CO3) are used for the preparation of LBO, NBO and KBO glasses respectively. The ABO glasses are irradiated with 100 MeV O7+ ion beam using 15 UD Pelletron tandem accelerators for fluences like 1 × 1011, 5 × 1011, 1 × 1012, 5 × 1012 and 1 × 1013 ions/cm2. The electronic energy loss is predominant and depth of propagation is calculated from SRIM and TRIM. The XRD and FE-SEM confirm the transformation of polycrystalline structure and growth of grains on the surface after the O7+ ion irradiation. LBO glasses at higher fluences revealed lithium tetrahydroxohexaoxopentaborate trihydrate with a monoclinic structure. The sharp and well-defined XRD peaks affirmed the transition from glass to glass ceramics after the irradiation. Formation of grains on the surface of the ABO glasses after the O7+ ion irradiation confirms the glass ceramics nature. KBO glasses possess enhanced stability even under ion irradiation. The optical bandgap decreased under ion irradiation. O7+ ion irradiation leads to a decrease in the tail of the Urbach energy, indicating reduced disorder in the ABO glasses. The transmission efficiency of both ABO glasses and glass ceramics is evaluated through reflection loss (Lr), transmission coefficient (T), and metallization criteria (M) and the suitability of the ABO glasses for nonlinear optical applications are discussed.
EMERGING CONTAMINANTS AND EXTRACTION METHODS STRATEGY IN PULP AND PAPER INDUSTRIAL EFFLUENTS
(BODHI International Journal of Research in Humanities, Arts and Science, 2018) Muthulakshmi Andal N; Karthika S; Gayathri N S
Plenty of efforts have been put forth worldwide towards the environmental protection in recent years. The contribution of pulp and paper industries apart from their productions, significantly pollute water, air and soil through their direct and indirect discharges without adopting proper treatment technologies. Wastewaters from these industries possess large amounts of toxic inorganic moieties, exhibiting lesser biodegradability. The discharged effluents mark adverse impacts on human and environment. Many methods have been employed by researchers in treating these raw effluents let out from paper and pulp industries. This review discusses the advancement in research findings employing novel chelating methods for the contaminants like colour, BOD, COD, Suspended Solids, heavy metals from the aforesaid wastewaters, and also provides a baseline on environment protection initiatives in lieu of measures taken for creating a healthy environment.
EVOLUTION OF CLASS ROOM – TEACHING CHALLENGES
(Vivekananda College, Madurai, 2011-08-01) Balavijayalakshmi J; Karthika S
Education means the process by which character is formed, strength of mind is increased, and intellect is sharpened, as a result of which one can stand on one’s own feet. This paper, at first deals with the basic principles, advantages and drawbacks of the ancient system of education – the gurukula system, which is learning by serving. It is followed by the analysis of the present day education system which has given rise to a group of Indian intelligentsia that is influenced in a big way by social, political, economic norms of western world and their way of living. Educators have the opportunity to make a huge impact on students, but with that opportunity comes many challenges. With an increasingly diverse student population, instructors face the challenge of dealing with students who have different values and ethics from their own. Today, more than ever before, students need to be engaged and motivated in the classroom. With the growing use of the Internet, information literacy includes the ability to recognize valid and accurate information. For building an ideal structure for education, an amalgamation of eastern culture and western methods, liberal thinking and advancement in science and technology of the West would be the best for future generations. It will be good if the forces of both – culture and systems – could be combined and a charter of an ideal education blueprint could be evolved for future generations.
GAMMA IRRADIATION-INDUCED CHANGES IN THE STRUCTURAL, OPTICAL, ELECTRICAL AND RADIATION SHIELDING PROPERTIES OF LITHIUM BORATE GLASSES
(Elsevier, 2023-01) Karthika S; Marimuthu K; Evangelin Teresa P; Meena R.C; Sulania I; Asokan K; Shanmuga Sundari S
Lithium borate glass with the chemical composition 25Li2O–75B2O3 (LBO) was prepared using the melt quenching technique. The changes in their structural, optical and electrical parameters due to gamma irradiation were investigated and its radiation shielding ability was discussed. The as-prepared glasses were transparent, colourless and inclusion free. The glasses were irradiated for 20, 40, 60, 80 and 100 kGy using a60Co gamma source having a dose rate of 2.906 kGy/h. As the radiation dose increases colour centres were formed in the LBO glass, for higher dosages the glasses turned black. The theoretical structural parameters such as density, optical basicity, ionicity, boron-boron separation, bond density, molar volume and oxygen packing density were calculated. The structural changes were carried out using x-ray diffraction confirming the amorphous nature even after a high dose of gamma irradiation. Gamma irradiation induces the formation of BO4. The bandgap decreases from 3.72 to 3.64 eV with an increase in the dose of gamma irradiation. The dielectric spectroscopy and A.C. conductivity mechanism of the glasses were analyzed. The activation energy of the glasses was calculated before and after gamma irradiation using the Arrhenius plot. High doses of gamma irradiation resulted in an increase in activation energy of LBO glasses which increases from 0.12 eV to 0.42 eV at 100 kHz frequency. The radiation shielding ability of the prepared glass samples was estimated using theoretical simulations by Phy-X/PSD software.
AN INFLUENCE OF WASTEWATER DISCHARGES FROM PAPER MILLS ON FARM PRACTICES
(IOP Science, 2022) Karthika S; Muthulakshmi Andal N
Industrial development is a challenging issue in recent times, as its adverse impact directly influences the environment. Paper and pulp industries are generally declared as one of the highly polluting industries in the country. However, nowadays they are also identified as the industry mounting with environmental and economic pressures to reduce the volume and toxicity of generated industrial wastewaters. Paper industries generate varieties of contaminants depending upon the manufacturing process. Especially, disposal of polluted water directly affects the soil structures, not only in industrial area but also in agricultural fields. Therefore, the present work accentuates on the examination of paper effluent characteristics, its impact on soil quality, and germination of groundnut seedlings. Seedling growth in polluted soil and fertile soil were monitored for 90 days. For this process, effluent, soil samples were collected from the paper industry located in Coimbatore district, Tamil Nadu, India. Soil samples were tested for their nutrients' level, concentration of heavy metals as per the standard quality procedures. Distribution of nutrients, heavy metal concentrations were studied in the matured crops. Sample crop registered mixed concentration of nutrient levels/heavy metals against the prescribed WHO/FAO standards, whereas control crop exhibited values within standards sufficing its healthier growth. This implies that the irrigation of the farmland with industrial water alters nutrient availabilities, in turn promoting toxic leachates into the soil. Further, the soil performances due to the percolation of industrial discharges reflected in the complexities of crop growth.
STRUCTURAL AND OPTICAL PROPERTIES OF LITHIUM BORATE GLASSES UNDER EXTREME CONDITIONS OF ION IRRADIATION
(IOP Science, 2023-07-05) Karthika S; Asokan K; Marimuthu K; Evangelin Teresa P; Ramcharan, Meena; Durairajan A; MA, Valente; Meena P; Shanmuga Sundari, Sankaran
Lithium borate (LBO) glasses of the composition 10LiO2.90B2O3 were prepared by melt quenching technique and characterized for morphological, structural, and optical properties before and after the exposure to the extreme conditions of 100 MeV Ni ion irradiation. Both the morphological images and structural properties confirm the transformation of LBO glasses from amorphous to polycrystalline nature. This Ni irradiation provides thermal energy that causes the ceramization of glass. The beam interacts with the material where the top layer of the glass remelts, and ultrafast re-solidification occurs after the termination of the ion beams. The Rietveld refinement using the x-ray diffraction data shows that the irradiated LBO possesses a monoclinic crystal structure of lithium pentaborate pentahydrate (B5H10LiO13). The FTIR spectra of Ni ion irradiated glasses show the creation of non-bridging oxygens (NBO) by the formation of BO4 units at the expense of BO3 units. The direct band gap and the Urbach energy of the glasses are affected by the nickel ion irradiation and are in the range 2.73 to 2.55 eV and 0.59 to 0.42 eV. The refractive index also reveals a minor change (1.66 to 1.63). The molar electronic polarizability, metallization criteria, and transmission coefficient were estimated. The coexistence of crystalline and amorphous phases leads to a multiscale phase structure that has multilevel relaxation processes. This is a suitable condition for the improvement of the rheological properties of glass and glass ceramics. Future work involves optimization of the coexistence of these two phases during irradiation.