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Heavy metal deposition temperature tuned spin pumping efficiency control in permalloy/tantalum bilayers
No full textSpin pumping is a key property for spintronic application that can be realized in heavy metal/ferromagnet bilayers. Here we demonstrate the possibility of improving spin pumping in permalloy (Py)/tantalum (Ta) bilayers through control of Ta heavy metal deposition temperature. Through a combination of structural and ferromagnetic resonance based magnetization dynamics study, we reveal the role of Ta deposition temperature in improving spin mixing conductance which is a key parameter for spin pumping across the Py/Ta interface. The results show that by depositing Ta above room temperature, a high spin mixing conductance of 7.7 �1018 m?2 is obtained with ?-Ta layer. The results present an understanding of the correlation between heavy metal deposition temperature and interface structure improvement and consequent control of spin pumping in Py/Ta bilayers. � 2023 Elsevier B.V., All rights reserved
Preferential concentration of particles in a decaying isotropic turbulence in the dilute regime
No full textThe gravitational settling of small solid particles in an incompressible decaying turbulence is investigated using the Eulerian-Lagrangian framework. We were able to reach a Taylor microscale-based Reynolds number, R e λ = 71 , on a mesh size of 128 3 . There is an increase in the mean settling velocity of the particles in a turbulent flow compared to that in a static flow. This increase in the settling velocity decreases with time in the case of decaying turbulence. The particle dynamics is found to be modified by the decaying turbulent flow, resulting in a relatively uniform distribution. The highest decay rate of particles is observed when S t = O ( 1 ) . Consequently, the de-clustering of the particles is also found to be peaked at S t = 1 . The trademark columnar accumulation of particles also disappears at low Froude numbers when the turbulence decays over time. For light particles, the distribution correlates well with low-vorticity regions, which disappears for heavy particles as gravity dominates the distribution for heavy particles in both forced and decaying turbulence. We have also analyzed the distribution quantitatively by plotting the Voronoi tessellation. We have found the distribution of Voronoi cell areas to be highly skewed to very low values due to the effect of clustering of particles
Synthesis and Characterization of Novel Graphene Nanoplatelet-Based Nanofibers for Thermal Energy Storage
No full textThe recent progress in nanofiber research has demonstrated the potential for improving the physical properties of materials through the integration of graphene nanoplatelets (GNP). This study involves the synthesis and characterization of novel GNP-infused polyvinylpyrrolidone (PVP) electrospun nanofibers. The required precursor solution was prepared using dimethylformamide (DMF) as a solvent, and that included 1.5 wt.% concentrations of GNP with 20 wt.% of PVP in 10 mL of DMF solution. The investigation using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed the morphology of the fibers with the distribution of graphene nanoplatelets. The zeta potential analysis demonstrates that the GNP/PVP nanofibers exhibit significant stability across a wide pH range, particularly in highly acidic and basic conditions. The thermogravimetric analysis (TGA) analysis showed exceptional thermal stability, with minimal weight loss until 300-400°C. The degradation of the PVP matrix was observed beyond 400°C. The results of the study show that GNP/PVP nanofibers have significant potential for specific applications in thermal management and energy storage under controlled temperature conditions
Online authentication habits of Indian users
No full textPasswords have been long used as the primary authentication method for web services. Weak passwords used by the users have prompted the use of password management tools and two-factor authentication to ensure better account security. While prior studies have studied their adoption individually, none of these studies focuses particularly on the Indian setting, which is culturally and economically different from the countries in which these studies have been done in the past. To this end, we conducted a survey with 90 participants residing in India to better understand the mindset of people on using password managers and two-factor authentication (2FA).
Our findings suggest that a majority of the participants have used 2FA and password managers in some form, although they are sometimes unaware of their formal names. While many participants used some form of 2FA across all their accounts, browser-integrated and device-default password managers are predominantly utilized for less sensitive platforms such as e-commerce and social media rather than for more critical accounts like banking. The primary motivation for using password managers is the convenience of auto-filling. However, some participants avoid using password managers due to a lack of trust in these tools. Notably, dedicated third-party applications show low adoption for both password manager and 2FA.
Despite acknowledging the importance of secure password practices, many participants still reuse passwords across multiple accounts, prefer shorter passwords, and use commonly predictable password patterns. Overall, the study suggests that Indians are more inclined to choose default settings, underscoring the need for tailored strategies to improve user awareness and strengthen password security practices
Unveiling Physical Conditions and Star Formation Processes in the G47 Filamentary Cloud
No full textWe present a multiwavelength study of the filamentary cloud G47 (d ∼ 4.44 kpc), which hosts the mid-infrared bubbles N98, B1, and B2. The SMGPS 1.3 GHz continuum map detects ionized emission toward all the bubbles, marking the first detection of ionized emission toward the B2 bubble. Analysis of the unWISE 12.0 μm image, the Spitzer 8.0 μm image, and the Herschel column density and temperature maps reveals two previously unreported hub-filament system candidates associated with the H ii regions B2 and N98, which are powered by massive OB stars. This indirectly favors the applicability of a global nonisotropic collapse scenario for massive star formation in N98 and B2. The position-position-velocity diagram of FUGIN 13CO (1-0) shows significant velocity variations from 61 to 53 km s−1 toward areas between B2 and N98, where the magnetic field morphology exhibits significant curvature and high velocity dispersion (i.e., 2.3-3.1 km s−1) is observed. This may be explained by the expansion of the H ii regions B2 and N98. The energy budget of the cloud, estimated using SOFIA/HAWC+ and molecular line data, suggests that the magnetic field dominates over turbulence and gravity in G47. Furthermore, the radial column density and velocity profiles of G47 display signatures of converging flows in a sheet-like structure. The relative orientations between the magnetic field and local gravity suggest that G47 may undergo gravitational contraction along the magnetic field lines once it becomes magnetically supercritical
Benchmarking quantum chaos from geometric complexity
No full textRecent studies have shown that there is a strong interplay between quantum complexity and quantum chaos. In this work, we consider a new method to study geometric complexity for interacting non-Gaussian quantum mechanical systems to benchmark the quantum chaos in a well-known oscillator model. In particular, we study the circuit complexity for the unitary time-evolution operator of a non-Gaussian bosonic quantum mechanical system. Our results indicate that, within some limitations, geometric complexity can indeed be a good indicator of quantum chaos
STEP: simultaneous tracking and estimation of pose for animals and humans
No full textWe introduce STEP, a novel framework utilizing Transformer-based discriminative model prediction for simultaneous tracking and estimation of pose across diverse animal species and humans. We are inspired by the fact that the human brain exploits spatiotemporal continuity and performs concurrent localization and pose estimation despite the specialization of brain areas for form and motion processing. Traditional discriminative models typically require predefined target states for determining model weights, a challenge we address through Gaussian Map Soft Prediction (GMSP) and Offset Map Regression Adapter (OMRA) Modules. These modules remove the necessity of keypoint target states as input, streamlining the process. Our method starts with a known target state in the initial frame of a given video sequence. It then seamlessly tracks the target and estimates keypoints of anatomical importance as output for subsequent frames. Unlike prevalent top-down pose estimation methods, our approach doesn't rely on per-frame target detections due to its tracking capability. This facilitates a significant advancement in inference efficiency and potential applications. We train and validate our approach on datasets encompassing diverse species. Our experiments demonstrate superior results compared to existing methods, opening doors to various applications, including but not limited to action recognition and behavioral analysis
Design and Development of New Benzopyrazole Derivatives as Selective Inhibitors of Helicobacter pylori IMPDH
No full textHelicobacter pylori (H. pylori) is a Gram-negative bacterial pathogen responsible for gastritis, peptic ulcers, and gastric cancer. Current treatment regimens involve triple or quadruple antibiotic therapies; however, the rise in antibiotic resistance necessitates the development of alternative therapeutic strategies. This study explores the potential of targeting H. pylori inosine-5-monophosphate dehydrogenase (HpIMPDH), a crucial enzyme in purine nucleotide biosynthesis essential for bacterial proliferation. A novel series of benzopyrazole derivatives was designed and synthesized as potential HpIMPDH inhibitors. Biochemical assays revealed that the synthesized compounds exhibited potent inhibitory activity, with SN-8.1 and SN-8.2 displaying IC50 values of 0.122 and 0.187 µM, respectively. These compounds showed minimal inhibition of human IMPDH2, suggesting selectivity toward the bacterial enzyme. Molecular docking studies further confirmed strong binding affinities at the HpIMPDH active site. Cytotoxicity assays indicated that the compounds were nontoxic at the tested concentrations. These findings demonstrate that benzopyrazole-based HpIMPDH inhibitors offer a promising strategy for the development of new anti-H. pylori agents