Browsing by Author "Nagaraja, H.S."

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A comprehensive study uncovering physical, structural, and optical properties of Cu2O and TiO2-reinforced borosilicate glasses as optical filters
(Elsevier B.V., 2024) Raghuvanshi, V.; Rashmi, I.; Ingle, A.; Shashikala, H.D.; Nagaraja, H.S.
In this study, the integration of transition metal oxides (TMOs), specifically Cu2O and TiO2, into a borosilicate glass matrix (30SiO2–35B2O3–35Na2O–5CaF2-X (TMO)) was investigated for enhanced glass functionality. Glass samples with varying TMO concentrations (X = 0, 1, 2, 3, 4 mol%) were prepared using the melt-quenching technique. X-ray diffraction confirmed the amorphous nature of the synthesized samples, while FTIR analysis showed structural changes, transitioning from trigonal BO3 to BO4 tetrahedra, alongside the formation of non-bridging oxygen species due to TMO integration. UV–Vis spectroscopy demonstrated a red shift in optical absorption profiles, correlating with a reduction in the indirect band gap as TMO content increased. Photoluminescence studies showed distinct behaviors, with Cu2O suppressing emission peaks and TiO2 exhibiting intriguing blue and green emissions, diminishing at higher concentrations. It was attributed that Cu2O had a larger impact on altering the glass network than TiO2. These findings contribute to understanding the properties of Cu2O and TiO2-containing borosilicate glasses, suggesting tailored optical properties for potential applications as bandpass filter and UV blocker. © 2024 Elsevier B.V.
A large-scale-oriented growth of ZnO nanorod array on glass substrate: Growth, structural and photoluminoscent properties
(National Institute of Optoelectronics, 2014) Santhosh Kumar, A.S.; Nagaraja, H.S.
We report a modified sol gel route for one step fabrication of large scale arrays of zinc oxide (ZnO) nanorods. The method is seed layer free, and nanorods are directly attached to a substrate. We studied the effect of PVA content on growth, crystallanity, orientation, microstructure and optical properties of ZnO. The XRD patterns confirm that samples grown with PVA have good crystallanity with (002) preferred orientation. The SEM micrographs show that the 1 Wt% PVA assisted grown films are covered with large scale oriented nanorod array. Raman spectrum represents that the 1 wt% PVA assisted grown ZnO nanostructures are highly crystalline with a hexagonal wurtzite phase. The room temperature PL spectrum exhibits a strong and sharp UV emission, which confirms that the grown arrays have good optical properties with few structural defects such as oxygen vacancies and zinc interstitials.
A study on the influence of geometric coordination of cobalt ions on the structural, physical and optical properties of borosilicate glass
(Elsevier Ltd, 2025) Raghuvanshi, V.; Rashmi, R.; Ingle, A.; Shashikala, H.D.; Nagaraja, H.S.
This work explores the synthesis and characterization of cobalt oxide-added borosilicate glass using the melt-quenching technique. The glass system was investigated using various methods, including X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), density measurements, UV–vis spectroscopy, photoluminescence, and electron paramagnetic resonance (EPR) spectroscopy. XRD validated the glass's amorphous nature, while FTIR results indicated significant bonding alterations, showing a transition from BO3 to BO4 units and from B3-O-Si to B4-O-Si linkages. The increased glass density further supported the formation of BO4 units. XPS analysis verified the presence of Co2+ and Co3+ ions within the glass matrix. Optical absorption studies revealed distinct electronic transitions for Co2+ ions in both tetrahedral and octahedral coordination, and for Co3+ ions in octahedral coordination, which was corroborated by EPR spectroscopy. The paramagnetic nature of Co2+ ions was analyzed, and the g-value was determined using X-band frequency. The study also noted the narrowing of the indirect band gap with the rise in the content of Co3O4, and the examination of the metallization criterion suggested a potential metallic nature for the synthesized glasses. Notably, the 0.05 mol% Co3O4-added sample exhibited a 48 % transmission rate and the highest emission, highlighting its potential as an optical bandpass filter. These findings underscore the versatility and tunability of cobalt oxide-added borosilicate glass for various optical technologies. © 2024 Elsevier Ltd and Techna Group S.r.l.
Adsorption and photocatalytic properties of NiO nanoparticles synthesized via a thermal decomposition process
(Cambridge University Press, 2018) Ramesh, M.; Rao, M.P.C.; Anandan, S.; Nagaraja, H.S.
NiO nanoparticles (NPs) were synthesized at different annealing temperatures via a thermal decomposition process and characterized using X-ray diffraction, scanning electron microscopy, and UV-vis spectroscopy. The NiO NPs prepared at higher annealing temperature (400 °C) were shown excellent adsorption and photocatalytic activity toward textile dyes reactive black 5 (RB-5) and methylene blue (MB). About 87.2% of RB-5 in 60 min and 70.2% of MB in 5 h was removed using NiO NPs synthesized at 400 °C. The photocatalytic degradation of MB was found to increase with an increase in the annealing temperature of the catalyst. Moreover, the kinetic study revealed that the adsorption and photocatalytic activity of NiO NPs followed the second and first-order kinetics, respectively. The enhanced performance of NiO NPs toward dye removal might be related to its optical and structural properties. © Materials Research Society 2018.
Advanced Electrolyte Additives for Lithium-Ion Batteries: Classification, Function, and Future Directions
(American Chemical Society, 2025) Brijesh, K.; Jareer, M.; Lakshmi Sagar, G.; Mukesh, P.; Alagarsamy, A.; Mandal, D.; Nagaraja, H.S.; Shahgaldi, S.
Lithium-ion batteries (LIBs) are widely employed as energy storage devices, particularly in portable electronics and electric vehicles, owing to their high energy density and efficiency. Among the key components of LIBs, the electrolyte plays a crucial role in determining capacity, cycling stability, rate performance, the electrode/electrolyte interface, and overall battery efficiency. However, traditional electrolytes face significant challenges, including severe structural degradation and interfacial side reactions under high-voltage and high-temperature conditions. Protective layers, such as the cathode-electrolyte interphase (CEI) and solid-electrolyte interphase (SEI), are essential for addressing these issues. These layers inhibit electron transfer while allowing lithium-ion (Li+) transport, preserving the structural and electrochemical integrity of the battery. A cost-effective strategy to further enhance the electrode-electrolyte interface and boost LIB performance is the incorporation of carefully designed electrolyte additives. While some articles discuss the use of electrolyte additives in LIBs, there is a lack of detailed studies classifying these additives based on their chemical composition-based grouping. Such a classification enables a more focused examination of the roles and mechanisms by which these additives improve LIB performance. This review paper bridges this gap by examining various electrolyte additives and their contributions to enhancing the safety and performance of next-generation LIBs. It provides valuable insights into the current progress and challenges associated with additives in liquid electrolytes. The article is organized into seven sections, addressing boron-based electrolyte additives (Section 2), sulfur-based electrolyte additives (Section 3), phosphorus-based electrolyte additives (Section 4), fluorine-based electrolyte additives (Section 5), and nitrogen-based electrolyte additives (Section 6). Each section discusses specific examples, the formation of SEI and CEI layers, and the electrochemical properties of these additives. Furthermore, the article concludes with a summary and outlook, advocating for continued advancements in electrolyte engineering for LIBs. © 2025 American Chemical Society.
Aluminum doped ZnO thin films by RF sputtering of coaxial ZnO and Al targets
(2011) Nagaraja, K.K.; Kumar, A.S.; Nagaraja, H.S.
Transparent conducting aluminum doped zinc oxide (AZO) films were deposited on glass substrates by radio (RF) frequency magnetron sputtering employing zinc oxide and aluminum targets. The targets are fixed coaxially in one cathode, by using a center hollow aluminum disc. Gas pressure was kept constant and the sputter power was varied. The nature of AZO film was found to be polycrystalline with hexagonal structure and a preferred orientation along c-axis. The Al content in the films is determined using EDXA analysis and it is found to vary with the applied power. Surface morphology of the films was found to be uniform and has fine grained structure. Electrical resistivity of the deposited films was found to be as low as 26�10-4?-cm for the film deposited at 250 W. The average transparencies up to 85% in the visible region were obtained for all the films. Optical band gap of the films show a slight blue shift as indicated by the (?h?)2 v/s h? plots. In the present investigation we have controlled Al content in the films by adjusting the power to the coaxial targets. The value of resistivity was found to decrease with the amount of Al present in the sample. � 2011 American Institute of Physics.
Aluminum doped ZnO thin films by RF sputtering of coaxial ZnO and Al targets
(2011) Nagaraja, K.K.; Santhosh Kumar, A.S.; Nagaraja, H.S.
Transparent conducting aluminum doped zinc oxide (AZO) films were deposited on glass substrates by radio (RF) frequency magnetron sputtering employing zinc oxide and aluminum targets. The targets are fixed coaxially in one cathode, by using a center hollow aluminum disc. Gas pressure was kept constant and the sputter power was varied. The nature of AZO film was found to be polycrystalline with hexagonal structure and a preferred orientation along c-axis. The Al content in the films is determined using EDXA analysis and it is found to vary with the applied power. Surface morphology of the films was found to be uniform and has fine grained structure. Electrical resistivity of the deposited films was found to be as low as 26Ã—10-4Î©-cm for the film deposited at 250 W. The average transparencies up to 85% in the visible region were obtained for all the films. Optical band gap of the films show a slight blue shift as indicated by the (Î±hÎ½)2 v/s hÎ½ plots. In the present investigation we have controlled Al content in the films by adjusting the power to the coaxial targets. The value of resistivity was found to decrease with the amount of Al present in the sample. Â© 2011 American Institute of Physics.
Cerium doping of FeS2 for the effective hydrogen evolution reaction (HER) electrocatalysis
(Taylor and Francis Ltd., 2025) Hegde, A.P.; Gonde, A.; Kumawat, A.; Mukesh, P.; Lakshmisagar, G.; Kumar, A.; Nagaraja, H.S.
Crafting and developing nanostructured electrocatalyst materials that are both active and stable plays a pivotal role in the shift toward economically viable hydrogen production through electrochemical water splitting, paving the way for the future replacement of fossil fuels. Such materials need to be cost-effective, simple to produce, and durable. In this context, the current research delves into improving the hydrogen evolution reaction (HER) electrocatalytic performance by incorporating cerium (Ce) into iron disulfide (FeS2) catalysts, using an uncomplicated hydrothermal fabrication approach. The study systematically examines the effects of various Ce doping levels on electrocatalytic activity. Notably, the catalyst with 15% Ce doping demonstrated exceptional efficiency, reducing the overpotential to 369 mV at 100 mA cm?2 current density. This enhanced performance can be attributed to the reduction in total charge-transfer resistance and a significant increase in the electrochemical active surface area (ECSA). Furthermore, the durability assessment of the 15% Ce-doped sample revealed its ability to sustain its catalytic activity for over 100 h under a continuous HER operation at 300 mA cm-2, with low performance-falloff. These results highlight the potential of Ce-dopping of FeS2 catalysts as a formidable choice for achieving efficient and long lasting HER electrocatalysis. © 2025 Taylor & Francis Group, LLC.
Chemically prepared Polypyrrole/ZnWO 4 nanocomposite electrodes for electrocatalytic water splitting
(Elsevier Ltd, 2019) Brijesh, K.; Bindu, K.; Shanbhag, D.; Nagaraja, H.S.
ZnWO 4 , PPy, and PPy/ZnWO 4 nanoparticles were prepared using chemical synthesis. The structural, compositional and morphological properties of the prepared samples have been investigated using XRD, FTIR, SEM, and HRTEM respectively. The powder XRD reveals the monoclinic wolframite structure for both ZnWO 4 and PPy/ZnWO 4 nanocomposite. SEM confirms the wrapping of ZnWO 4 with PPy. The electrodes of ZnWO 4 , PPy, and PPy/ZnWO 4 have been tested as bifunctional electrocatalyst towards HER and OER using constant current chronopotentiometry (CP) and Linear Sweep Voltammetry (LSV). The electrochemical surface area and the electrocatalytic activity PPy/ZnWO 4 nanocomposite towards HER and OER are greater than that of pure ZnWO 4 and PPy. The Tafel slope of PPy/ZnWO 4 nanocomposite is 76 and 84 mV dec ?1 in 0.5 M H 2 SO 4 and 1 M KOH at room temperature for HER and OER respectively. The results suggest that PPy/ZnWO 4 nanocomposite is a good candidate for the bifunctional electrocatalyst for water splitting. © 2018 Hydrogen Energy Publications LLC
Conversion of microfiltration membrane into nanofiltration membrane by vapour phase deposition of aluminium for desalination application
(2011) Padaki, M.; Isloor, A.M.; Nagaraja, K.K.; Nagaraja, H.S.; Pattabi, M.
Preparation and modification of NF membrane are challenging aspects in research. In the present work, we have synthesised Polysulfone (PSf) microfiltration membrane and reduced the pore size to nano level by physical vapour deposition (PVD) of aluminium metal. Membrane pore size was reduced from micro pore to nano pore, which rejected 42.22% of NaCl from the solution with 164L/m2h. And also water permeation decreases from 1.10324-10-10 to the 9.141-10-12. The SEM and AFM pictures showed the surface modification and metal deposition in the pores. The performance of the membrane was studied by dead end flow cell using 3.5% of NaCl solution, in which PVD membrane showed 42.22% of rejection with 16.4L/m2h flux. Thermal analysis from DSC showed Tg of 265°C. Contact angle measurement, and water uptake were also reported. © 2011 Elsevier B.V.
Corrosion Behaviour and Characterization of Thermal Sprayed Coating of Nickel Chromium Cermet on Low Carbon Steel
(2018) Amudha, A.; Shashikala, H.D.; Nagaraja, H.S.
Corrosion is the major problem faced by Navy, especially when pumps, ship impellers and other components have to work in harsh environments like sea water. Therefore, high corrosion resistant metal ceramic matrix 75Cr3C2- 25 (NiCr) cermet has been one of the good choices for coating. In this study, we are discussing the HVOF (High Velocity Oxy Fuel) coating of 75Cr3C2-25(NiCr) on the low carbon steel substrate, IS 2062 grade B. The as coated samples were annealed at 600�C for 1 hour, 2hour and 3hours. The electrochemical tests were conducted for corrosion evaluation. Structural analysis was done by using X-Ray diffraction technique. Microstructure and thickness of the coating was studied using Scanning Electron Microscopy (SEM). Density measurement studies were done on as-coated and annealed coupons. � 2017 Elsevier Ltd.
Corrosion Behaviour and Characterization of Thermal Sprayed Coating of Nickel Chromium Cermet on Low Carbon Steel
(Elsevier Ltd, 2018) Amudha, A.; Shashikala, H.D.; Nagaraja, H.S.
Corrosion is the major problem faced by Navy, especially when pumps, ship impellers and other components have to work in harsh environments like sea water. Therefore, high corrosion resistant metal ceramic matrix 75Cr3C2- 25 (NiCr) cermet has been one of the good choices for coating. In this study, we are discussing the HVOF (High Velocity Oxy Fuel) coating of 75Cr3C2-25(NiCr) on the low carbon steel substrate, IS 2062 grade B. The as coated samples were annealed at 600Â°C for 1 hour, 2hour and 3hours. The electrochemical tests were conducted for corrosion evaluation. Structural analysis was done by using X-Ray diffraction technique. Microstructure and thickness of the coating was studied using Scanning Electron Microscopy (SEM). Density measurement studies were done on as-coated and annealed coupons. Â© 2017 Elsevier Ltd.
Corrosion protection of low-cost carbon steel with SS-309Mo and Inconel-625 bimetallic weld overlay
(Institute of Physics Publishing helen.craven@iop.org, 2019) Mudha, A.A.; Shashikala, H.D.; Nagaraja, H.S.
The dissimilar weld overlay coatings of components can lead to corrosion. In the present work, two different weld overlay layers (SS-309Mo and Inconel-625) are deposited on IS2062 grade B carbon steel, in order to avoid distortions and improve corrosion resistance. The microstructural investigations revealed that the intermediate layer SS-309Mo on carbon steel prevents the dilution by aiding crack-free weld overlay of Inconel-625 on the top. The corrosion behaviour of the coatings is studied using Linear Polarization Resistance and the Electrochemical Impedance Spectroscopy. The corrosion rate of the coatings decreased by two orders of magnitude compared to that of low carbon steel substrate. The corrosion rate of the deposited Inconel-625 along with intermediate SS-309Mo is 1.16×10-3 and is comparable to that of bare Inconel-625 (1.12×10-3 mmpy). Further, the immersion tests for 14 days show that, the depositions are stable with the formation of the passive film. ©2019 IOP Publishing Ltd.
Design and fabrication of spectrally selective TiAlC/TiAlCN/TiAlSiCN/TiAlSiCO/TiAlSiO tandem absorber for higherature solar thermal power applications
(Elsevier, 2015) Jyothi, J.; Chaliyawala, H.; Srinivas, G.; Nagaraja, H.S.; Barshilia, H.C.
A new nanostructured TiAlC/TiAlCN/TiAlSiCN/TiAlSiCO/TiAlSiO tandem absorber has been designed for higherature solar thermal power applications. The first three layers in this tandem act as an absorbing layer, whereas, TiAlSiCO and TiAlSiO act as semi-transparent and anti-reflecting layers. The tandem absorber was deposited on stainless steel substrates using a four-cathode reactive direct current unbalanced magnetron sputtering system. The composition and thicknesses of the individual component layers have been optimized by adjusting the reactive flow rate of C2H2, N2, O2, and also Al, Ti and Si target power densities to achieve high absorptance (0.961) and low emittance (0.07 at 82 °C). The reflectance data showed that the absorptance increases gradually with shift of reflectance minimum to higher wavelengths from first layer to last layer (i.e., TiAlC to TiAlSiO). The thickness of optimized tandem absorber was calculated from the cross-sectional field-emission scanning electron microscopy images and confirmed using transmission electron microscopy. The performance evaluation of the tandem absorber has been evaluated by heating it in air and vacuum under cycling conditions at different temperatures. These results showed that the tandem absorber was stable up to 325 °C in air for 400 h and up to 650 °C in vacuum for 100 h, thus demonstrating its suitability for higherature solar thermal power generation applications. © 2015 Elsevier B.V. All rights reserved.
Dual electrochemical application of r-GO wrapped ZnWO4/Sb nanocomposite
(Institute of Physics Publishing helen.craven@iop.org, 2019) Brijesh, K.; Bindu, K.; Amudha, A.; Nagaraja, H.S.
ZnWO4/Sb nanorods and r-GO-ZnWO4/Sb nanocomposite have been prepared using a single step solvothermal method. The prepared nanocomposites have been characterized using x-ray diffractometer (XRD), Scanning Electron Microscope (SEM), High Resolution Transmission Electron Microscope (HR-TEM), Raman and Brunauer-Emmett-Teller (BET). The x-ray photoelectron spectroscopy (XPS) technique was used to determine the elemental composition of ZWS-5 (5 mg r-GO-ZnWO4/Sb) composite. The XRD reveals the monoclinic wolframite structure of ZnWO4/Sb and r-GO-ZnWO4/Sb. SEM and HRTEM confirms that the ZnWO4/Sb has been decorated on the r-GO sheets. The electrochemical performance of the prepared samples towards the Hydrogen Evolution Reaction (HER) and dopamine sensing has been tested using electrochemical techniques. Onset potential of 265 mV @10 mA cm-2, lower Tafel slope (95 mV dec-1), high electrochemical surface area (1383.216 m2g-1) and high specific site density (18.551 06 × 1021 g-1) of ZWS-5 reveals the high electrocatalytic activity of the composite towards HER. Chronoamperometric dopamine sensing shows that ZWS-5 has the superior sensing performance with highest specific sensitivity (723 ?A ?M-1 ?g-1), lowest limit of detection (0.9624 ?M), along with a good selectivity. Results suggest that the r-GO-ZnWO4/Sb nanocomposite is a good candidate for the HER and electrochemical dopamine sensor. The incorporation of r-GO nanosheets with ZnWO4/Sb (ZWS) nanorods enhances the specific and electrochemical surface area, which accounts for the high electrocatalytic activity of the composite. © 2019 IOP Publishing Ltd.
Dual storage mechanism of Bi2O3/Co3O4/MWCNT composite as an anode for lithium-ion battery and lithium-ion capacitor
(Elsevier B.V., 2024) Lakshmi Sagar, G.; Brijesh, K.; Mukesh, P.; Hegde, A.P.; Kumar, A.; Kumar, A.; Bhat, K.S.; Nagaraja, H.S.
Bismuth oxide(Bi2O3) and cobalt oxide(Co3O4) are promising owing to their unique properties, high storage capacity, low cost, and eco-friendliness, making them ideal for lithium-ion batteries(LIBs) and lithium-ion capacitors(LICs) anodes. This study presents the synthesis and thorough characterization of Bi2O3/Co3O4 and Bi2O3/Co3O4/MWCNT composites as potential LIB and LIC anode materials. The materials are synthesized using a hydrothermal process succeeded by annealing. Structural, morphological, and compositional studies were analyzed. Various tests evaluated electrochemical performance, including cyclic voltammetry(CV), confirming a dual storage mechanism like alloying and conversion reaction involved for better energy storage. Specific discharge capacities of 834 mAh/g and 1184 mAh/g were recorded for Bi2O3/Co3O4 and Bi2O3/Co3O4/MWCNT composite electrodes at a current density of 100 mA/g, respectively. The composite material exhibited notably enhanced rate capability, with 31 % and 51 % discharge capacities for Bi2O3/Co3O4 and Bi2O3/Co3O4/MWCNT, respectively. The cyclic stability assessment revealed that Bi2O3/Co3O4 and Bi2O3/Co3O4/MWCNT maintained a high coulombic efficiency of around 99 % over 250 charge–discharge cycles at a high current density of 1 A/g. The capacity retention was approximately 253 mAh/g for Bi2O3/Co3O4 and 439 mAh/g for the Bi2O3/Co3O4/MWCNT composite, indicating excellent cyclic stability and minimal energy loss during cycling. Moreover, the LICs assembly of Bi2O3/Co3O4/MWCNT//CB was investigated, revealing a power density of 200 W kg?1 alongside an energy density of 8.64 Wh kg?1. The cyclic stability assessment over 10,000 cycles exhibits a capacity retention of approximately 45 % under a high current density of 2 A/g. © 2024 Elsevier B.V.
Effect of annealing on the structural and nonlinear optical properties of ZnO thin films under cw regime
(2013) Nagaraja, K.K.; Pramodini, S.; Poornesh, P.; Nagaraja, H.S.
We report on the studies of the effects of annealing on the structural and third-order nonlinear optical properties of ZnO thin films deposited on quartz substrates by the RF magnetron sputtering technique. The films were annealed in the temperature range 400-1000 °C. The third-order nonlinear optical studies were carried out using the z-scan technique under continuous wave (cw) He-Ne laser irradiation at 633 nm wavelength. The effects of annealing on the structural properties were examined using x-ray diffraction and atomic force microscopy (AFM). The (0 0 2) preferred orientation increased with increase in annealing temperature up to 800 °C. The crystalline phases of SiO2 were observed at higher annealing temperatures. The appearance of an extraneous phase was confirmed by AFM images and optical transmittance spectra. The samples exhibited nonlinear absorption and nonlinear refraction under the experimental conditions. The negative sign of the nonlinear refractive index n2 indicated that the films exhibit self-defocusing property due to thermal nonlinearity. The nonlinear refractive index n2, the nonlinear absorption coefficient ?eff and the third-order optical susceptibility ?(3) were found to be of the highest orders. The estimated value of third-order optical susceptibility ?(3) was of the order of 10-3 esu. Multiple diffraction rings were observed when the samples were exposed to the laser beam. The appearance of rings was due to the refractive index change and thermal lensing. With increase in laser intensity, the variations of the self-diffraction ring patterns were studied experimentally. The films also exhibited strong optical limiting properties under cw laser excitation, and reverse saturable absorption was the dominant process leading to the observed nonlinear behaviour. © 2013 IOP Publishing Ltd.
Effect of binary zinc-magnesium oxides on polyphenylsulfone/cellulose acetate derivatives hollow fiber membranes for the decontamination of arsenic from drinking water
(Elsevier B.V., 2021) Kumar, M.; Isloor, A.M.; Todeti, S.R.; Nagaraja, H.S.; A.F., A.F.; Susanti, R.
Arsenic contamination is continuously threatening the safety of drinking water in many parts of the world. The consumption of chronic arsenic contaminated drinking water can cause serious health related issues. Therefore, the synthesis of novel materials is very much essential for the selective removal of arsenic from aqueous solution. In the present investigation, the effect of increased concentrations (0.6, 1.0 and 1.5 wt%) of binary zinc-magnesium oxide (ZnO-MgO) on cellulose acetate (CA)/polyphenylsulfone (PPSU) and cellulose acetate phthalate (CAP)/PPSU hollow fiber membranes for arsenic removal was performed. As used ZnO-MgO was characterized by using x-ray diffraction (XRD), transmission electron microscopy (TEM) and particle size distribution. Fabricated hollow fiber membranes were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), zeta potential, fourier transform infrared (FTIR), x-ray photoelectron spectrophotometer (XPS), thermogravimetric analysis (TGA) and antifouling studies. The results revealed that, there is significant enhancement in the overall performance of the ZnO-MgO containedmembranes. An enhancement of arsenic removal properties was demonstrated from 0.6 wt% of ZnO-MgO in CAP/PPSU (ZMCAP-0.6) membrane was 81.31% with the retention permeability of 69.58 L/m2h bar respectively. Similarly, 1 wt% of ZnO-MgO in CA/PPSU (ZMCA-1) was found to be 78.48% and 198.47 L/m2h bar respectively using 1 ppm laboratory prepared aqueous arsenic solution (pH 6.8 ± 0.2) at 1 bar transmembrane pressure. In addition, improved antifouling properties was noticed with an increased flux recovery ratio and enhanced thermal stability from ZnO-MgO contained membranes. Therefore, as fabricated ZnO-MgO contained membranes provided enhanced arsenic removal tendency without compromising the retention permeability. © 2020
Effect of Composition on Designed Tandem Absorber to Achieve Selective Properties for High Temperature Solar Thermal Applications
(2017) Jyothi, J.; Nagaraja, H.S.; Barshilia, H.C.
We have designed a tandem absorber comprising of five layers namely:TiAlC / TiAlCN / TiAlSiCN / TiAlSiCO / TiAlSiO on stainless steel substrate by DC unbalanced magnetron sputtering system.Tandem absorber shows a high absorptance of 0.961 with an emittance of 0.15 by careful optimization of flow rates and thicknesses of the individual layers. Further, the detailed effects of reactive gas flow rates and thicknesses of each individual layers on the optical properties were studied. Growth rate and thicknesses of each individual layers of the tandem absorber were studied by cross-section FESEM images. The tandem absorber shows long term thermal stability when annealed in vacuum at 600�C for more than 750 h under cyclic heating conditions, indicating suitability of the tandem absorber for solar thermal high temperature applications. � 2017 Elsevier Ltd. All rights reserved.
Effect of Composition on Designed Tandem Absorber to Achieve Selective Properties for High Temperature Solar Thermal Applications
(Elsevier Ltd, 2017) Jyothi, J.; Nagaraja, H.S.; Barshilia, H.C.
We have designed a tandem absorber comprising of five layers namely:TiAlC / TiAlCN / TiAlSiCN / TiAlSiCO / TiAlSiO on stainless steel substrate by DC unbalanced magnetron sputtering system.Tandem absorber shows a high absorptance of 0.961 with an emittance of 0.15 by careful optimization of flow rates and thicknesses of the individual layers. Further, the detailed effects of reactive gas flow rates and thicknesses of each individual layers on the optical properties were studied. Growth rate and thicknesses of each individual layers of the tandem absorber were studied by cross-section FESEM images. The tandem absorber shows long term thermal stability when annealed in vacuum at 600Â°C for more than 750 h under cyclic heating conditions, indicating suitability of the tandem absorber for solar thermal high temperature applications. Â© 2017 Elsevier Ltd. All rights reserved.