Muon (g-2) from the bulk neutrino field in a warped extra dimensional model

In the Randall-Sundrum model, a bulk neutrino field in the 5-dimensional space-time can give rise to tiny Dirac masses to neutrinos. In such a scenario, we have computed the contribution of the bulk neutrino field to the anomalous magnetic moment $(g-2)_\mu$ of muon. We have computed this contribution in the 't Hooft-Feynman gauge and have found that the contribution has the right sign to fit the current discrepancy between the experiment and the standard model value of $(g-2)_\mu$. We have also studied possible constraints on the model parameters by including contributions to $(g-2)_\mu$ from other sources such as bulk gravitons.Comment: 18 pages, 3 figures, 2 tables, minor changes, this version has been published in Physical Review

A Study of solitary pulmonary nodule in 50 cases

54% of Solitary Pulmonary Nodule in the study was malignant. 26% cases were of infective origin – tuberculosis and pneumonia / lung abscess. 14% cases were benign and 6% were indeterminate lesion. • 48% of the malignancies were squamous cell carcinoma, 33% were adenocarcinoma and 10% were small cell carcinoma. • Commonest malignancy in SPN was squamous cell carcinoma. Inordinately high number of smokers in study population probably predisposed to higher incidence of squamous cell carcinoma. • Symptoms and signs were not conclusive. 50% cases were asymptomatic or had vague ill-health. 40% had cough with or without sputum. Minimal non-specific lung signs (50%) or no elicitable physical sign (25%) were predominant findings. • 22% cases only could be diagnosed early enough for a favourable treatment response. • Exclusively males were found to have malignancy in SPN, though female sample size was very low (no. 2) in this study. • 72% of SPNs above 60 yrs of age were malignant. But even at age 25 yrs, Small Cell Carcinoma has developed. • 82% of study population were smokers, 81% of > 40 pack yrs smokers had developed malignancy. • 18% of SPNs were diabetics and were mostly having infective pathology. • Most important characteristic feature of SPN is margin and size of the lesion in x – ray. • 94% of spiculated margin and 72% of size >4 cm diameter nodules were malignant. 88% of <3cm nodules were benign/infective origin. • 65% of nodules with contrast enhancement of > 20 HU in CT were malignant. • 2 cases of indeterminate pathology could be diagnosed of benign pathology only on basis of benign pattern of doubling time. • Both transthoracic aspiration cytology / biopsy and fibre – optic bronchoscopy and lavage / brushing / biopsy were important diagnostic tools in carefully selected patients with yield of > 80%. Overall, transthoracic aspiration cytology / biopsy were slightly more efficacious as a diagnostic measure. • Fine needle aspiration cytology / biopsy of lymph nodes were conclusive in palpable lymph nodes

Exploring Axions through the Photon Ring of a Spherically Symmetric Black Hole

In this study, we examine the phenomenon of photon axion conversion occurring in the spacetime surrounding a black hole. Specifically, we focus on the potential existence of a magnetic field around the supermassive black hole M87*, which could facilitate the conversion of photons into axions in close proximity to the photon sphere. While photons traverse through the curved spacetime, they spend time near the photon sphere, where conversion of these photons into axions takes place. Consequently, this process leads to a decrease in the intensity of the black hole's photon ring. To explore the possibilities of detecting these hypothetical axion particles, we propose observing the photon sphere using higher resolution telescopes. By doing so, we can gain valuable insights into the conversion mechanism as well as the nature of the spherically symmetric black hole geometry. Moreover, we also investigate how the photon ring luminosities are affected if the black hole possesses a charge parameter. For instance apart from U(1) electric charge, the presence of extra dimension may induce a {\em tidal charge} with a characteristic signature. It is important to note that the success of the conversion mechanism relies on the axion-photon coupling and mass. As a result, the modified luminosity of the black hole's photon ring offers a valuable means of constraining the axion's mass and coupling parameter within a certain range. Thus our findings contribute to a better understanding of photon axion conversion in the environment of a black hole spacetime and helps us explore the possible existence of extra spatial dimension

X-ray tomography study on porosity in electron beam welded dissimilar copper–304SS joints

Dissimilar joining of copper (C10300) to AISI–304 Stainless Steel (SS) sheets was performed using Electron Beam Welding (EBW) process. EBW was performed for two weld conditions such as with beam oscillation and without beam oscillation. X-ray Computed Tomography (XCT) technique was used for three-Dimensional (3D) visualization and quantification of porosity in the weld region. It was observed that the application of beam oscillation resulted in less porosity and the average pore size was found to be smaller as compared to without beam oscillation condition. Also, pores were found to be uniformly distributed in the weld incase of with beam oscillation as compared to without beam osicllaition condition. Further, it was observed that there exists an optimum beam oscillation diameter beyond which there is no positive effect of beam oscillation in controlling the porosity formation in the weld joint

Microstructure and mechanical properties of electron beam welded dissimilar steel to Fe-Al alloy joints

Electron beam welding (EBW) technique was used to perform dissimilar joining of plain carbon steel to Fe-7%Al alloy under three different weld conditions such as with beam oscillation, without beam oscillation and at higher welding speed. The effect of weld parameters on the microstructure and mechanical properties of dissimilar joints was studied using optical microscopy, SEM, EBSD, hardness, tensile and erichsen cup tests. Microstructure results show that the application of beam oscillation resulted in uniform and homogeneous microstructure compared to without beam oscillations and higher welding speed. Further, it was observed that weld microstructure changes from equiaxed to columnar grains depending on the weld speed. High weld speed results in columnar grain structure in the weld joint. Erichsen cup test results show that the application of beam oscillation results in excellent formability as compared to high weld speed. Tensile test results show no significant difference in strength properties in all three weld conditions, but the ductility was found to be highest for joints obtained with the application of weld beam oscillation as compared to without beam oscillation and high weld speed. This study shows that the application of beam oscillations plays an important role in improving the weld quality and performance of EBW dissimilar steel to Fe-Al joints

Effect of beam oscillation on porosity and intermetallics of electron beam welded DP600-steel to Al 5754-alloy

Formation of porosity and intermetallic compounds (IMCs) were studied in electron beam welded (EBW) DP-600 steel to Al-5754 dissimilar alloy joints at three different weld conditions such as without beam oscillation, with beam oscillation and with varying beam oscillation diameter. X-ray Diffraction (XRD), scanning electron microscopy (SEM), microhardness, three-dimensional X-ray computed tomography (XCT) were used to characterize porosity and IMCs distribution in these weld joints. Beam oscillation with optimum oscillation diameter (1 mm diameter) improved the weld quality by reducing the amount, maximum size and percentage of pores in weld zone significantly. For IMCs, average size increased little bit but maximum size, percentage of formation and amount reduced. By increasing oscillation diameter (2 mm diameter) beyond optimum value (1 mm diameter), quality of joints was found to deteriorate with accompanying higher pore density, average pore size, average IMCs size etc. Raman spectroscopy and Leco gas analyzer were also used to identify and quantify the entrapped gases in the weld joint

Effect of weld parameters on porosity formation in electron beam welded Zircaloy-4 joints : X-ray tomography study

Zircaloy-4 to Zircaloy-4 (Zr-4) similar butt joints were prepared using Electron Beam Welding (EBW) technique under different weld conditions such as with beam oscillation, without beam oscillation and at different welding speeds. Three-dimensional (3D) visualisation of porosity in weld joints was carried out using X-ray computed tomography (XCT) technique. Quantification of porosity such as the average size, number and shape of the pores were evaluated and compared among weld joints produced under different conditions. XCT results show that the porosity of the welds increased substantially with the increase in the weld speed. More interestingly, the results also show that there is a significant decrease in porosity of the joint produced with beam oscillation condition. An increase in weld speed from 700 mm/min to 1000 mm/min resulted in a significant increase in pore density (from 16 to 313 per mm3) and it was observed that the average size of the macro pores increased from 96.4 μm to 121.5 μm. The joints prepared with beam oscillation produced least number of pores with minimum percentage of macro pores and maximum percentage of spherical pores in it. Raman spectroscopy results confirmed the presence of hydrogen gas in pores of all the weld joints