Indian Institute of Information Technology, Design and Manufacturing, Kurnool

Appalla S., Valluri S.P., Yaswanth K.N., Vejandla K., Gunturu C., Jagapathi G., Prashanth N.N., Prabu A.V.

Puduru V.K., Yakkati R.R., Pardhasaradhi B., Babu K.S., Cenkeramaddi L.R.

Neeraja V., Thota N., Chandra G.H., Raghavender M., Reddy D.A., Y. P V.S.

Semiconducting characteristics of antimony-based chalcogenides in the recent past gained the utmost attention for photovoltaic (PV) cells and photo electrochemical (PEC) hydrogen evolution. In the current research endeavour, a simple hydrothermal route has been employed to prepare polycrystalline Sb2S3 thin films. Under ideal temperature conditions of 120 oC, Sb2S3 films were prepared in an autoclave, varying the reaction times between 10:00 and 14:30 h with an interval of 30 min. Further heat treatment of the as-synthesized Sb2S3 thin films was carried out on an electric hot plate at 200 °C for 90 min. XRD analysis of heat-treated Sb2S3 films unveiled an orthorhombic crystal structure with (310) predominant plane. Consequently, the crystallite sizes, displayed improvement from ∼ 33 to 77 nm, with reaction periods for 10:00 h to 13:30 h and decreased after that. The five distinct Raman modes were spotted at 155, 190, 236, 280, and 305 cm-1, further confirming the single-phase formation of Sb2S3 thin films. SEM and EDS analysis indicated conspicuous variations in surface morphology and stoichiometric ratios of antimony and sulfur elements. The Sb2S3 thin films deposited at 120 °C for 13:30 h are found to be nearly stoichiometric (Sb and S are 42.61 and 57.39 at. %). The resultant oxidation states were demonstrated to be (+3) and (-2) for antimony and sulphur respectively. All the thin films exhibited an optical absorption coefficient greater than 104 cm-1 with a direct energy band gap ranging between 1.43-1.61 eV. The Sb2S3 thin films deposited for 13:30 h have unveiled the highest photocurrent density of -0.27 mA/cm2, indicating a potential photocathode for hydrogen production.

K.N.G.B Y., Sivaprasad V., Prashanth N.N., Salunkhe S., Mahdal M., Gunturu C.

AbstractGeneralized frequency division multiplexing (GFDM) is a flexible block‐structured multi‐carrier scheme recently proposed for next‐generation wireless communication systems. There are various approaches suggested for its analysis and implementation via simulations but testing in real‐time environments is not heavily investigated. This paper carries out the real‐time implementation of the GFDM system utilizing software‐defined radio (SDR) by emphasizing mainly channel estimation and synchronization. Symbol timing, frequency offset, and channel estimate algorithms are applied using a windowed preamble with two identical halves to satisfy low egress noise requirements. Time and frequency estimation is evaluated in terms of residual offsets along with symbol error rate over frequency selective channels. This algorithm is extended to a preamble composed of multiple identical parts. This facilitates a large frequency estimation range at the cost of complexity. For practical validation of the above concepts, the National Instruments (NI) universal software radio peripheral (USRP) 2953R is employed as hardware and it is interfaced with LabVIEW.

Kumar N.V., Pandiyarajan T., Vipindas K.

In this study, h-Boron Nitride (h-BN) nanosheets have been successfully exfoliated using Bougainvillea flower extract and ultrasonication process. The microstructural parameters such as microstrain, stress, and energy density were calculated using Williamson–Hall analysis. The time of ultrasonication and post-annealing temperature significantly alter the microstructure parameters such as crystal size, microstrain, stress, and energy density upon sonication. The lattice constants such as a-axis and c-axis, cell volume, and bond length did not alter significantly which confirms that there is no crystal structure deformation upon sonication and annealing processes. FESEM result revealed that exfoliation of h-BN and ultrasonication duration greatly influenced the exfoliation. Raman and FTIR studies confirm the pure phase of h-BN without secondary impurities. A simple ultrasonication process would effectively exfoliate h-BN layers and this could be used for tribological applications to reduce the friction between rubbing surfaces.

Pandey V., Seetharam R., Chelladurai H.

In research, high-entropy alloy-reinforced metal matrix composites (HEAs-MMCs) have attracted academicians, researchers, and scientists to achieve extraordinary properties unobtainable by ceramic-reinforced metal matrix composites. HEAs have potential to improve the properties of weak metal matrices due to their superior properties such as high strength, stability in high-temperature applications, improved corrosion, and wear resistance. HEA has novel properties over conventional alloy system including exceptional performance at high temperatures, improved mechanical properties in cryogenic environments and high strength with ductility. The rapidly evolving needs of industries require high-performance materials, and HEA-MMCs are suitable for fulfilling the demands of newly established application fields.In this review article, the author discusses fabrication methods, microstructural evolution, mechanical, wear, thermal, electrical and corrosion properties, effects of heat treatment and strengthening mechanisms of HEA-MMC materials. HEA-MMC is suitable for large-scale and mass production with complex and precise HEA-MMC parts fabricated by commercialization of the casting process and additive manufacturing technology. The core-shell structure is formed by the diffusion action between the matrix and the reinforced and acts as a transition layer, leading to an improvement in mechanical properties. Finally, from the strengthening mechanisms, it was concluded that fine grain strengthening, Orovan strengthening and coefficient of thermal expansion (CTE) imbalanced strengthening mechanisms were more effective than others in improving properties. At the end of the review paper, the main importance, applications, challenges and perspectives of HEAs-MMCs are discussed, which will help the development of advanced materials with improved performance that can increase progress and innovation in the scientific community.

Sudheer A.E., Tejaswini G., Posselt M., Murali D.

We design a novel class of Janus structures PbXY (X,Y = F, Cl, Br, I) and propose it for the solar mediated photocatalytic water splitting hydrogen production and for the bulk photovoltaic effect. The relaxed layers show a strong variation of the structural parameters which is due to the electronegativity of the halide atoms. The stability of the Janus structures is investigated using formation energy, phonon spectra, elastic constants and Ab-Initio Molecular Dynamics simulations. Using differential charge density calculations and Bader charge analysis, it is found that the atomic bonds may have covalent or ionic character, which depends on the halide atoms in top and bottom layers of the Janus structure. Electronic structure calculations are performed using the GGA functional and the more precise HSE functional. From the band structure, band gap and effective masses of electrons and holes are determined. The large difference between the mobility of both charge carriers as well as the built-in electrical dipole indicate beneficial conditions for charge separation and suppression of charge recombination. The calculated optical absorption spectra show that the Janus structures are suitable for UV-visible light absorption. Based on VBM and CBM calculation using the HSE functional it is demonstrated that the novel PbXY Janus layers are suitable for water splitting reaction, i.e. for the use as a photocatalyst.

Panachikkool M., E T A., Pandiyarajan T.

Several simulation studies have been conducted in copper bismuth oxide (CuBi2O4) based solar cells (SCs) using SCAPS-1D simulator, demonstrating a high photoconversion efficiency (PCE) of up to 33 % under ideal conditions. The introduction of non-ideal conditions such as resistive losses, optical, and recombination losses could provide the actual performance of the SC. In this letter, we applied all nonideal conditions to the SC structure consisting of Mo/CuBi2O4/TiO2/ITO/Al with varied thicknesses of absorber layer of CuBi2O4 from 50 nm to 2 µm and evaluated the photovoltaic (PV) parameters and PCE of SCs. Under ideal conditions, cells exhibited a PCE of 31.23 % and 3.55 % with an absorber layer thickness of 2000 nm and 50 nm, respectively. The introduction of nonideal conditions with an absorber layer thickness of 50 nm, exhibited a drastic reduction of PCE from 3.55 to 0.46 % and other PV parameters such as open circuit voltage (Voc) from 1.19 to 1.04 V, short circuit current density (Jsc) from 4.27 to 0.77 mA/cm2, and fill factor (FF) from 69.40 to 56.42 %. The increase in thickness of the absorber layer further to 2000 nm did not improve the PCE of SC.

Umadevi K., Clementina R., Sundeep D., Ali M.I., Chary R.N., Shankaralingappa A.

The recent Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) pandemic has posed significant challenges to global healthcare, with a myriad of impacts on the human body, particularly noted in hemostatic abnormalities observed in COVID-19 patients. These abnormalities have been linked to an increased risk of serious thrombotic events like deep vein thrombosis, pulmonary embolism, and stroke. Unlike existing literature, this comprehensive review delves into the long-term implications of these abnormalities, providing invaluable guidance for ongoing patient care as we move into the post-pandemic era. We cover the entire spectrum of hemostatic abnormalities, including elevated levels of aPTT, D-dimer, PT, ferritin, INR, fibrinogen, fibrin, and FDP, all of which create a complex clinical scenario necessitating vigilant monitoring and targeted therapeutic interventions. With a focus on the heightened risk of thrombotic complications, we underscore the importance of timely anticoagulant therapy and other necessary interventions, tailored to the patient's unique clinical presentation. This review stands as a critical resource for clinicians, hematologists, and healthcare providers, equipping them to navigate the complexities of COVID-19 in both acute and long-term settings, ensuring optimal patient outcomes. As we collectively navigate the lasting impact of the pandemic, this targeted and in-depth analysis becomes an indispensable tool in advancing our understanding and management of COVID-19.

Khan A., Maity K.

PurposeTo explore a hybrid approach in order to attain optimal cutting conditions proficient of generating adequate dimensional accuracy in combination with virtuous surface finish during turning of commercially pure titanium (CP-Ti) grade 2.Design/methodology/approachIn the present paper, an application of the hybrid fuzzy–VIKOR method has been proposed to estimate an optimal combination of process variables during turning of commercially pure titanium (CP-Ti) grade 2. Three distinct input factors, namely, cutting speed, feed rate and depth of cut, were selected, each varied at three levels. Thus, a series of experiments were performed based on Taguchi's 3-factor-3-level (L27) orthogonal array. The major attention was given to acquire minimum cutting force and flank wear along with good surface finish. The adequacy of the proposed methodology was verified with the help of ANOVA test.FindingsThe results of the investigation revealed that the suggested hybrid technique is quite effective, easily understandable and time-saving approach, which can be successfully implemented to solve various problems either of similar or of different kinds.Originality/valueIncreasing demand of qualitative as well as low cost products is identified as the main challenging task in the current competitive market. Therefore, estimation and selection of the most suitable machining environment are of paramount importance in a real-time manufacturing system. Machining process involves both qualitative and quantitative factors, may be conflicting in nature, all to be considered together. Consequently, an appropriate combination of the machining variables is evidently desirable to meet the aforesaid challenges effectively.