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Constraining the physical parameters of XTE J1701-462 through NuSTAR observations
The spectral properties of the transient neutron star low-mass X-ray binary XTE J1701-462 were studied using the data obtained from FPMA/B detectors onboard NuSTAR during its second known outburst (2022 September). The physical parameters of the system were derived from the analysis of the data in the 3.0-30.0 keV energy range. The patterns displayed on the hardness-intensity diagram of the three observations closely resembled the banana branch/normal branch, a vertex of horizontal and normal branch of the Z-track and a transition from normal branch to flaring branch. Spectral analysis of the source revealed the presence of Fe K emission complex. The source spectra were fitted with a multitemperature blackbody () component in conjunction with the reflection model (). The values of temperature (kTin) and radius (Rin) of the inner accretion disc obtained from the spectral fitting with the model combination - + showed the source to be in its soft spectral state during the observations. The inclination angle (?) of the source was estimated to be between 19 and 33 and the inner disc radius (Rin) was found to be 17.4 km. Assuming the case of magnetic truncation of accretion disc, the upper limits for the magnetic dipole moment (?) and the magnetic field strength (B) at the poles of the neutron star in the system were found to be 5.78 1026 G cm3 and 8.23 108 G, respectively, for kA = 1. 2024 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. -
Spectral Properties of the Soft X-Ray Transient MAXI J0637-430 Using AstroSat
Soft X-ray transients are systems that are detected when they go into an outburst, wherein their X-ray luminosity increases by several orders of magnitude. These outbursts are markers of the poorly understood change in the spectral state of these systems from the low/hard state to the high/soft state. We report the spectral properties of one such soft X-ray transient: MAXI J0637-430, with data from the SXT and LAXPC instruments on board the AstroSat mission. The source was observed for a total of ?60 ks in two observations on 2019 November 8 and 21 soon after its discovery. Flux-resolved spectral analysis of the source indicates the presence of a multicolor blackbody component arising from the accretion disk and a thermal Comptonization component. The stable low temperature (?0.55 keV) of the blackbody component points to a cool accretion disk with an inner disk radius of the order of a few hundred kilometers. In addition, we report the presence of a relativistically broadened Gaussian line at 6.4 keV. The disk-dominated flux and photon power-law index of ?2 and a constant inner disk radius indicate the source to be in the soft state. From the study we conclude that MAXI J0637-430 is a strong candidate for a black hole X-ray binary. 2022. The Author(s). Published by the American Astronomical Society. -
Spectro-temporal and type I X-ray burst analysis of GX 3+1 using AstroSat observations
GX 3+1, an atoll type neutron star low-mass X-ray binary, was observed four times by Soft X-ray Telescope and The Large Area X-ray Proportional Counter on-board AstroSat between 2017 October 5 and 2018 August 9. The hardness-intensity-diagram of the source showed it to be in the soft spectral state during all the four observations. The spectra of the source could be adequately fit with a model consisting of blackbody (bbody) and powerlaw (powerlaw) components. This yielded the blackbody radius and mass accretion rate to be ?8 km and ?2 10?9 M? y?1, respectively. In one of the observations, a type I X-ray burst having a rise and e-folding time of 0.6 and 5.6 s, respectively, was detected. Time-resolved spectral analysis of the burst showed that the source underwent a photospheric radius expansion. The radius of the emitting blackbody in GX 3+1 and its distance were estimated to be 9.19 +?00.8297 km and 10.17 +?00.1807 kpc, respectively. Temporal analysis of the burst yielded upper limits of the fractional root mean square amplitude of 7 per cent, 5 per cent, and 6 per cent during burst start, burst maximum, and right after the radius expansion phase, respectively. 2023 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. -
NuSTAR and AstroSat observations of GX 9+1: spectral and temporal studies
We have studied the spectro-temporal properties of the neutron star low-mass X-ray binary GX 9+1 using data from NuSTAR/Focal Plane Module and AstroSat/Soft X-ray Telescope and Large Area X-ray Proportional Counter (LAXPC). The hardness-intensity diagram of the source showed it to be in the soft spectral state (banana branch) during both observations. NuSTAR spectral analysis yielded an inclination angle (?) = 29 and inner disc radius (Rin) ? 19 km. Assuming that the accretion disc was truncated at the AlfvCrossed D sign ?0.9) with a monotonic increase in mass accretion rate () along the banana branch. The analysis also showed the presence of absorption edges at ?1.9 and ?2.4 keV, likely due to Si xiii and S xv, respectively. Temporal analysis with LAXPC-20 data in the 0.02-100 Hz range revealed the presence of noise components, which could be characterized by broad Lorentzian components. -
Comprehensive investigations on spectral and temporal features of GX 5-1 using AstroSat observations
Comprehensive spectrotemporal analyses of the Z-type neutron star low-mass X-ray binary GX 5-1 were performed using 10 broad-band observations from AstroSat/Soft X-ray Telescope and Large Area X-ray Proportional Counter (LAXPC) instruments. The LAXPC-20 hardness-intensity diagram showed horizontal and normal branches (HBs and NBs) of the Z track which exhibited secular motion. The time-averaged spectra in the energy range 0.7-25.0 keV could be fitted with the model combination -Cconstant tbabs edge edge thcomp diskbb. This yielded ? ?2, kTe ?3.3 keV, and Fdisc/Ftotal ? 0.8 indicating the soft/intermediate spectral state of the source during the observations. Flux-resolved spectral analysis revealed a positive correlation between kTin and Fbol. However, a negative correlation was observed between them in one of the NBs. Time-averaged temporal analysis revealed multiple HB oscillations (HBOs) and NB oscillations (NBOs), and peaked noise components in the ?5-50 Hz range. Furthermore, flux-resolved temporal analysis showed that the frequency of the HBOs correlates positively whereas the strength of HBOs correlates negatively with Fbol, indicating their probable origin from the accretion disc. In contrast, the frequency and strength of NBOs remain fairly constant with Fbol, suggesting that they originate from a different region in the system. Using the relativistic precession model along with highest frequency of the HBO, the upper limits of the magnetic dipole moment (?) and field strength (B) at the poles of the neutron star in the system were found to be 25.60 1025G cm3 and 3.6408 G, respectively, for kA= 1. 2024 The Author(s). -
Concentration-dependent luminescence characterization of terbium-doped strontium aluminate nanophosphors
The present investigation describes the synthesis of luminescent terbium-doped strontium aluminate nanoparticles emitting bright green light, which were synthesized through a solid-state reaction method assisted by microwave radiation. Various samples containing different concentrations of Tb were synthesized, and an analysis of their structural and morphological features was conducted using powder x-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The band gaps of the samples were determined utilizing the KubelkaMunk method. The quenching mechanism observed was identified to be due to dipoledipole interaction using the Dexter theory. The optimized sample with a terbium concentration of 4at.% has a luminescence lifetime of 1.05 ms with 20.62% quantum efficiency. The results of this study indicate that the terbium-doped strontium aluminate fluorescent nanoparticles exhibit promising potential for a wide range of applications, including bioimaging, sensing and solid-state lighting. 2024 John Wiley & Sons Ltd. -
Gravity modulation effect on ferromagnetic convection in a Darcy-Brinkman layer of porous medium
The influence of a timedependent body force on the threshold of convective instability in a magnetic fluid filled horizontal porous layer is investigated. The gravity modulation effect is treated by employing a perturbation method. The correction Rayleigh number is computedas a function of the modulation frequency, porous and magnetic parameters. It is expounded that, for small and reasonable values of the modulation frequency, gravity modulation and magnetic mechanism have opposing influence on the stability. The study further explicates that, when the gravity modulation frequency increases beyond all bounds, manifestation of the disappearance of the magnetic and porous medium effects on the stability is highly likely. Published under licence by IOP Publishing Ltd. -
Chemical Reaction-Driven Ferroconvection in a Porous Medium
The effect of chemical reaction on the outset of convection of a ferromagnetic fluid in a horizontal porous layer which is heated from below is studied using small perturbation method. Assuming an exothermic zero-order chemical reaction, the eigenvalues are found by employing the Galerkin method. The effect of magnetic parameters and Frank-Kamenetskii number is discussed. It is established that both magnetic forces and chemical reaction accelerate the threshold of ferroconvection. Further, the fluid layer is destabilized marginally when the nonlinearity of magnetization is strong enough. 2021, Springer Nature Singapore Pte Ltd. -
Porous medium convection in a chemically reacting ferrofluid with lower boundary subjected to constant heat flux
The effect of exothermic chemical reaction of zero-order on Bard-Darcy ferroconvection is investigated using the technique of small perturbation. The eigenvalues associated with an adiabatic lower wall are determined by employing the Galerkin method. The Darcy-Rayleigh number is computed in terms of the parameters pertaining to chemical reaction and ferromagnetic fluid. It is established that, when chemical reaction escalates, there is a considerable shift from linearity and occurrence of asymmetry in the basic temperature profiles. It is ascertained that the threshold of Bard-Darcy ferroconvection is augmented through the stresses of both mechanisms due to chemical reaction and magnetization, and the ferroconvective instability due to nonlinearity of magnetization is rather inconsequential when chemical reaction is present. It is also shown that the destabilizing feature of magnetic forces resulting from the fluid magnetization is less pronounced when chemical reaction is present. Published under licence by IOP Publishing Ltd. -
Fluorescence bioimaging applications of europium-doped strontium aluminate nanoparticles
Fluorescence bioimaging is widely used for physiological studies to visualise intercellular molecular events due to its highly selective, sensitive, and non-destructive nature. However, its application in in vivo live imaging is often limited by the scarcity of biocompatible fluorescent probes possessing optimal properties. Our study focuses on developing europium-based nanoparticles for in vivo bioimaging, especially imaging of plants. Eu-doped strontium aluminate nanoparticles were synthesised through a conventional solid-state reaction. Structural characterisation of samples using XRD confirmed the prevalence of SrAl2O4 as the prominent phase. The FTIR spectrum, SEM and TEM images were recorded for further characterization. Photoluminescence studies showed orange red emission of sample. The antibacterial activity of the nanophosphors was studied, demonstrating no antibacterial activity against Escherichia coli and Pseudomonas aeruginosa. Furthermore, in vitro cytotoxicity studies conducted using Neuro-2A cells showed no indications of cytotoxicity associated with europium doped strontium aluminate nanoparticles. When incorporated into the plant tissue culture medium, these nanoparticles were found to have no effect on seed germination and plant growth, and it demonstrated no phytotoxicity. Imaging studies have shown the uptake of nanoparticles by plants and their subsequent transport through the vascular system. Our results emphasise the direct integration of nanophosphors into plant tissues from the growth medium, eliminating the necessity for traditional staining methods in fluorescence bioimaging. Incorporation of nanophosphors into living organisms holds promise for non-invasive and long-term fluorescence imaging, with potential applications in biological studies and diagnostics. The outstanding fluorescence properties and biocompatibility of europium doped strontium aluminate nanoparticles broaden its potential for various applications in fluorescence bioimaging. 2024 Elsevier Ltd and Techna Group S.r.l. -
Tb-doped strontium aluminate nanophosphor: Cytotoxicity, phytotoxicity, and bioimaging in plant cells
This study explores the novel application of terbium-doped strontium aluminate nanoparticles for fluorescence imaging in plant cells. The study encompasses microwave assisted solid state synthesis as well as the structural and optical characterization of terbium-doped strontium aluminate nanophosphors, their toxicity studies in plant and animal cells and their use as a fluorescent dye for plant imaging. The X-ray diffraction pattern analysis, along with Rietveld refinement studies, show the formation of SrAl2O4 as a dominant crystalline phase. Photoluminescence investigations demonstrate green emission from Tb3+ transition levels. In vitro biocompatibility of terbium-doped strontium aluminate nanophosphors was studied using L929 fibroblast cells. The plant Clitoria ternatea was used to examine phytotoxicity. The samples' potential for bioimaging was further investigated. Our findings reveal improved growth of seedlings, positioning these nanoparticles as promising tools in plant-related research. This study advances our understanding of nanoparticle-plant interactions and holds potential for transformative applications in agriculture. 2024 The Authors -
En route to Khardung La with Dhak Dhak
Dhak Dhak uses the trope of a motorcycle road trip to discuss several societal and emotional barriers women ought to overcome to forge their own paths and blossom into their authentic selves. 2024 Economic and Political Weekly. All rights reserved. -
Synthesis and Characterisation of SrAl2O4: Eu3+ Orange-Red Emitting Nanoparticles
The current study involves the synthesis and characterisation of europium doped strontium aluminate nanophosphors using the solid-state reaction method with varying concentrations of europium. The existence of the SrAl2O4 phase in all samples was verified using X-ray diffraction and FTIR analysis. The lattice parameters as well as phase fractions were determined using Rietveld refinement. Surface morphology was studied using field emission scanning electron microscope. Using the Tauc plot method acquired from the diffuse reflectance spectra, the band gaps of the samples were determined and it was found that the doped samples possess lower band gaps compared to the host. Our findings demonstrate that these nanophosphors exhibiting bright orange-red emission under UV excitation with quantum efficiency 70.68%, can be applied for display and fluorescence imaging. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2023. -
Facilitating the New Normal: Challenges and Opportunities of Facility Management Companies in India
Covid 19 has brought the world to a standstill. The hospitality, Travel and tourism being affected the most due to travel restrictions across the world and within India. One of the sectors that have been affected majorly are the industries providing Facility Management services to core businesses. FM is dependent on the type of client business, the client organisation's structure and the market sector. This paper aims to gauge the impact of the pandemic on the Facility management companies in India. This also captures the positive and negative aspect of pandemic on the FM. An empirical research design has adopted to address the study objectives. This research involves both primary and secondary data. Primary data for the study have been collected in the form of structured questionnaire distributed among 300 respondents who are senior executives heading selected Facility Management companies in India. The target respondents have been selected based on simple random sampling to ensure the normal distribution of data. The Electrochemical Society -
Developing employment capacity: The impact of academic student organization on the students core competencies
The purpose of this research is to understand the relationship between developing employment capacity with the enhanced core competencies by participating in student body organizations while pursuing their undergraduate degree program. This research aims at understanding the Communication Skills of the Students Core Competencies that are affected by their participation in the student organizations. This research aims at understanding the overall Character Development of the student by their participation in the student organizations. This research aims at understanding the Critical Thinking skills of the students core competencies that are affected by their participation in the student organizations. This research aims at understanding the Career Development skills of the students core competencies that are affected by their participation in the student organizations. This research aims at understanding how the development in the students core competencies help in improving the students employment capacity. This is an empirical study carried out using primary and secondary methods of data collection. Literature of relevant topics were gathered and studied to assist in the study. A questionnaire was circulated to 350 respondents in order to gather information. This study shows that the students who are actively involved in student organizations develop core competencies that help them during employment. The study has proved the students develop better skills which are very useful for their life. The limitations of the study are that all the students do not develop similar skills because they play various different roles in the student organizations. Some students are less involved and the research does not take into consideration the degree of involvement. The study aims to ultimately create a system that measures the students performance and involvement in the organizations. The university can motivate students and encourage them to be more enthusiastic about participating in student organizations. 2020, Institute of Advanced Scientific Research, Inc.. All rights reserved. -
A Deep Learning Methodology CNN-ADAM for the Prediction of PCOS from Text Report
Text categorization is a popular piece of work in natural language processing (NLP) and machine learning, and Convolutional Neural Networks (CNNs) can be used effectively for this purpose. Although CNNs are traditionally associated with computer vision tasks, they have been adapted and applied successfully to text classification problems. In the proposed study Convolutional Neural Networks (CNNs) with adam optimization algorithm plays a crucial role in detecting PCOS words from sonographic text reports. 2023 IEEE. -
A STUDY ON ACCOUNTABILITY AND PERCEIVED AUTONOMY SUPPORT AMONG PRE-UNIVERSITY COLLEGE TEACHERS
ABSTRACT Accountability of Teachers referred to as teacher accountability in educational literature is a multi-dimensional concept consisting of teacher participation in school decision making. It further focuses on what is best for the student and the profession of teaching. Self-determination theory postulates that when teachers perceive an autonomy supportive work climate which satisfies their three core psychological needs, (Competence, Autonomy and Relatedness) they experience a feeling of wellness and belongingness to the institution and are energized to exert extra effort in all the activities of the institution they engage in. The present study on Accountability and Perceived Autonomy Support among Pre-university College Teachers undertaken by the investigator focused on the relationship between ??Accountability of Teachers and Perceived Autonomy Support among Pre-university college teachers of Bangalore north and south belonging to three types of management such as government, private aided and private unaided. The aim of this study was to find out whether there is any relationship between Accountability of Teachers and Perceived Autonomy Support. The sample of the study consisted of 392 pre-university college teachers (both male and female) of three types of colleges; namely government, private aided and private unaided. The results of the study show that there is a significant relationship between ??Accountability of Teachers and Perceived Autonomy Support among pre-university college teachers. Further female teachers are more accountable than their male counterparts and Married teachers are found be more accountable than unmarried teachers. It was also found that there is a significant difference in the Competence dimension of ??Perceived Autonomy Support among pre-university college teachers belonging to three types of management and the Private Aided pre-university college teachers have a higher level of Competence (dimension of Perceived Autonomy Support) compared to Private unaided pre-university college teachers. Private Aided Pre-university college teachers have higher level of Relatedness (dimension of Perceived Autonomy Support) as compared to Private unaided College Teachers. These findings give a clear indication to principals and administrators of private unaided pre-university colleges regarding the imperative need to implement appropriate strategies in order to enhance perceived autonomy support of their teachers. Key words: Accountability of Teachers, Perceived Autonomy Support, Pre-university college teachers -
Genuine handwriting variations in 10 years: a pilot study
Background: The present study aims to examine the extent of variation in genuine handwriting characteristics across 10years. One hundred samples (one admitted handwriting and three exemplars) were collected from 25 subjects (male and female, age ranging from 30 to 55) using purposive sampling technique. The admitted handwriting sample included documents like notebooks, wills, diaries, and record books that had been written 10years earlier, and 3 exemplars with the same information, written now in a similar kind of material. Both individual and class characteristics were analyzed in admitted as well as three exemplars which includes size of letters, slant, i-dot, t-bar (diacritics), humped letters (m, n, h), and formation of rounded letters (o, a, d, b, g, p, q). Results: Cohens kappa showed that there is a significant agreement between admitted and exemplars in the characteristics except for size. Conclusion: The results imply that once an adult has acquired a particular handwriting pattern, the master pattern of each letter, as well as both class and individual characteristics, remain unchanged. The size of the letters may change across age. 2019, The Author(s). -
Attitude of generations: Does it matter online?
Generational examinations are turning out to be necessary with the characteristics they exhibit. This research work aimed at establishing the interceding relationship of disposition of three distinctive generations-Generation X, Generation Y, and Generation Z. In complete, 1200 responses were acquired from both male and female respondents of each generational class dependent on online purchase data collected by employing Google Forms. For the investigation, the model utilized the SOR framework. The results indicated that attitude does not play a vital role in the purchase intention of Generation X followed by the partial mediation of attitude for Generation Y and full mediation effect for Generation Z. This steady increment of attitudinal change underpins the examination by setting up proof that every age shifts in their mentality and purchasing conduct. Online retailers must concentrate on showcasing systems and create online visual merchandising cues which outwardly advance and make a feeling of stimulating attitude for generations. The current study also added value to the existing literature by classifying the customer base not merely on age, but also on their technological perspective of distinguishing web atmospheric cues and catering to their needs from a generational outlook. The study also took into account the importance of the organism's role played by attitude in the S-O-R framework. In this manner, the study helps marketers to design methodologies and plan online visual marketing space for better generational reaction and benefit. 2021, Associated Management Consultants Pvt. Ltd.. All rights reserved. -
Linear and non-linear magneto-convection in couple stress fluid with non-classical heat conduction law
A theoretical examination of the thermal convection for a couple stress fluid which is electrically conductive and possessing significant thermal relaxation time with an externally applied magnetic field is carried out. Fourier's law fails when fluids are subjected to rapid heating or when it is confined and in the case of nano-devices. A frame invariant constitutive equation for heat flux is considered. The linear analysis is carried out implementing a normal mode solution and the non-linear stability of the system is analyzed using a double Fourier series. The analysis of the transfer of heat is determined in terms of the Nusselt number. Published under licence by IOP Publishing Ltd.