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R. Rajasekaran,A. K. Lakshminarayanan,M. Vasudevan,P. Vasantha Raja 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.11
The 316LN Stainless Steel (SS) weld joints were fabricated using Tungsten Inert Gas (TIG) Welding and Activated FluxTungsten Inert Gas (A-TIG) Welding techniques with suitable process parameters. Initially, basic mechanical properties wereevaluated across weld joints. Further microstructural study of the base metal, TIG, and A-TIG joints were accomplishedusing Optical Microscopy (OM), Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM)techniques. The microstructural characterization revealed higher grain size variations at the fusion zone of the A-TIG jointdue to the slow cooling rate and reversed Marangoni convection effect. The Stress Corrosion Cracking (SCC) susceptibilityof the TIG and A-TIG welded joints was assessed using five different loading/Stress conditions. The constant load boiling45 wt% Magnesium Chloride Hexahydrate (MgCl2.6H2O) solution as per ASTM G36-94 standard was used to evaluate theSCC susceptibility of the welded joints. The SCC (crack initiation and propagation) of the base metal and welded jointsoccurred by the anodic dissolution and Hydrogen Induced Cracking mechanisms. For the welded joints additionally, thedissolution of the δ-ferrite increased the crack growth rate. The A-TIG joint exhibited lesser SCC resistance than the TIGjoint for the following major reasons: (i) Formation of the large dendrites (ii) Presence of the higher grain size variations atthe fusion zone. Moreover, both welded joints showed lesser SCC resistance than the base metal due to the dissolution ofthe δ-ferrite and the residual stress formation. The fractographic studies for the base metal, TIG, and A-TIG joints revealedthe brittle nature of transgranular SCC failure.
M. Ramaprakash,R. Nivethida,A. Muthukrishnan,A. Jerom Samraj,M. G. Neelavannan,N. Rajasekaran The Korean Electrochemical Society 2023 Journal of electrochemical science and technology Vol.14 No.4
Ni-W/Al<sub>2</sub>O<sub>3</sub> nano-composites were electrodeposited on mild steel substrate for mechanical and corrosion resistance applications. This study focused on the preparation of Ni-W/Al<sub>2</sub>O<sub>3</sub> nano-composite coating with various quantity of Al<sub>2</sub>O<sub>3</sub> incorporations. The addition of Al<sub>2</sub>O<sub>3</sub> in the electrolytes were varied from 1-10 g/L in electrolytes and the Al<sub>2</sub>O<sub>3</sub> incorporation in Ni-W/Al<sub>2</sub>O<sub>3</sub> nano-composite coatings were obtained from 1.82 to 13.86 wt.%. The incorporation of Al<sub>2</sub>O<sub>3</sub> in Ni-W alloy matrix influenced the grain size, surface morphology and structural properties were observed. The distributions of Al<sub>2</sub>O<sub>3</sub> particle in alloy matrix were confirmed using electron microscopy (FESEM and TEM) and EDAX mapping analysis. The crystal structure informations were studied using X-ray diffraction method and it confirms that the deposits having cubic crystal structure. The better corrosion rate (0.87 mpy) and microhardness (965 HV) properties were obtained for the Ni-W/Al<sub>2</sub>O<sub>3</sub> nano-composite coating with 13.86 wt.% of Al<sub>2</sub>O<sub>3</sub> incorporations.
Two‐dimensional Ti 3 C 2 MXene for photocatalytic hydrogen production: A
Reghunath B. Shalini,Rajasekaran Sruthi,Mathew Sandra,Pinheiro Dephan,Devi K. R Sunaja,정시언,Jayaraman Theerthagiri,최명룡 대한화학회 2023 Bulletin of the Korean Chemical Society Vol.44 No.12
This study focuses on the utilization of two‐dimensional Ti 3 C 2 MXene as a catalyst for photocatalytic hydrogen production. MXenes, a class of transition metal carbides/nitrides, exhibit exceptional properties conducive to enhancing photocatalytic reactions. This research explores the performance of Ti 3 C 2 MXene as a cocatalyst in photocatalytic systems, aiming to improve charge separation, inhibit recombination, and facilitate efficient hydrogen evolution from water under light irradiation. The synthesis methods, catalyst‐loading strategies, and overall photocatalytic mechanisms are investigated, shedding light on the potential of Ti 3 C 2 MXene as a promising material for advancing hydrogen production through sustainable means. This study focuses on the utilization of two-dimensional Ti3C2 MXene as a catalyst for photocatalytic hydrogen production. MXenes, a class of transition metal carbides/nitrides, exhibit exceptional properties conducive to enhancing photocatalytic reactions. This research explores the performance of Ti3C2 MXene as a cocatalyst in photocatalytic systems, aiming to improve charge separation, inhibit recombination, and facilitate efficient hydrogen evolution from water under light irradiation. The synthesis methods, catalyst-loading strategies, and overall photocatalytic mechanisms are investigated, shedding light on the potential of Ti3C2 MXene as a promising material for advancing hydrogen production through sustainable means.
Studies on the growth, structural, optical and mechanical properties of ADP admixtured TGS crystals
T. Balu,T.R. Rajasekaran,P. Murugakoothan 한국물리학회 2009 Current Applied Physics Vol.9 No.3
Ammonium dihydrogen orthophosphate admixtured triglycine sulphate crystals have been grown from aqueous solution by slow evaporation technique. X-ray analysis showed a slight variation in the lattice parameters for admixtured crystals. The optical transmission spectra indicated a wide optical transparency in the entire visible and near IR region. Dielectric measurements revealed in shift of Curie point to lower temperature with increase in dopant concentration. Microhardness studies have shown that the hardness decreases with increase in ADP concentration. Ammonium dihydrogen orthophosphate admixtured triglycine sulphate crystals have been grown from aqueous solution by slow evaporation technique. X-ray analysis showed a slight variation in the lattice parameters for admixtured crystals. The optical transmission spectra indicated a wide optical transparency in the entire visible and near IR region. Dielectric measurements revealed in shift of Curie point to lower temperature with increase in dopant concentration. Microhardness studies have shown that the hardness decreases with increase in ADP concentration.
Tai Jesse W.,Sorkhi Samuel R.,Trivedi Ishika,Sakamoto Kyoko,Albo Michael,Bhargava Valmik,Rajasekaran Mahadevan Raj 대한남성과학회 2021 The World Journal of Men's Health Vol.39 No.3
Purpose: Puborectalis muscles (PRM) and ischiocavernosus muscles (ICM) play important roles in urinary continence and male erectile functions. Understanding of anatomy and surgical-injury related changes to these muscles is critical to monitor changes in continence or erectile function. Anatomical description of these muscles has undergone revisions because these conclusions were derived from cadavers. Our objectives were to: (i) elucidate male pelvic muscles by in-vivo magnetic resonance imaging (MRI) and 3-dimensional (3-D) reconstruction of these images and (ii) compare PRM and ICM thickness in healthy volunteers and symptomatic patients. Materials and Methods: Healthy young male (mean age, 25 years; n=5), older male (age, 65–70 years; n=5), and post-prostatectomy patients with erectile dysfunction and urinary incontinence (age, 65–70 years; n=5) were scanned on a 3T-magnetic resonance scanner. Images were acquired from slices above urinary bladder base to urethra entry into penis. Pelvic bone, bladder/urethra, corpus cavernosum, ICM, PRM, and prostate were segmented. 3-D models of each structure were generated and assembled into composite images, and ICM and PRM thicknesses were calculated. Results: We successfully reconstructed 3-D male pelvic floor anatomy including ICM, PRM, bladder, urethra, bulbospongiosus, corpus cavernosa, prostate and bones from the two groups. We documented significant reduction in PRM and ICM thickness in older men. Conclusions: This is perhaps the first 3-D reconstruction of male pelvic floor structures based on in-vivo MRI in healthy and symptomatic patients. Observed reduction in PRM and ICM thickness is possibly due to age-related atrophy.
Does Sarcopenia Increase the Risk for Fresh Vertebral Fragility Fractures?: A Case-Control Study
Ashish Anand,Ajoy Prasad Shetty,K. R. Renjith,Sri Vijay Anand K. S.,Rishi Mugesh Kanna,Shanmuganathan Rajasekaran 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.1
Study Design: Case-control study. Purpose: Sarcopenia is an age associated condition characterized by decrease in muscle mass, strength, and physical performance. We aimed to investigate whether sarcopenia increased the risk of vertebral fragility fractures among the elderly. Overview of Literature: Initial reports on sarcopenia suggest its contribution to the development of vertebral fragility fractures. However, recent studies showed contradictory findings. Methods: Fifty-one consecutive patients with vertebral fragility fractures and matched controls without fractures were evaluated for sarcopenia, T-score, body mass index, and presence of preexisting vertebral fractures. Sarcopenia was diagnosed as total psoas cross-sectional area (TPA) 2 standard deviations below normative value from normal young adults and decreased handgrip strength (26 kg for men and 18 kg for women). Univariate and multivariate analyses were performed using the fresh fracture occurrence as the dependent variable. Results: Sarcopenia was confirmed in 29.4% and 7.8% of cases and controls (p=0.005), respectively; 56.8% and 13.7% of cases and controls had previous vertebral fractures. Sarcopenia prevalence was greater among those with previous fractures (38% vs. 7.6%; odds ratio, 7.76; p<0.001). TPA was lower among the cases (1,278 mm2 vs. 1,569 mm2, p=0.001) and those with previous fractures (1,168 mm2 vs. 1,563 mm2, p<0.001). Handgrip strength was greater among those without previous fractures (19.6 kg vs. 16.3 kg, p=0.05). In multivariate analysis, sarcopenia was not identified as a significant predictor of fresh fractures whereas previous fractures and lower T-score were found to be significant. Conclusions: Sarcopenia is not an independent risk factor for fresh vertebral fragility fractures in the elderly.