467 research outputs found

    Propagating Disturbances along fan-like coronal loops in an active region

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    Propagating disturbances are often observed in active region fan-like coronal loops. They were thought to be due to slow mode MHD waves based on some of the observed properties. But the recent studies involving spectroscopy indicate that they could be due to high speed quasi-periodic upflows which are difficult to distinguish from upward propagating slow waves. In this context, we have studied a fan loop structure in the active region AR 11465 using simultaneous spectroscopic and imaging observations from Extreme-ultraviolet Imaging Spectrometer (EIS) on board Hinode and Atmospheric Imaging Assembly (AIA) on board SDO. Analysis of the data shows significant oscillations at different locations. We explore the variations in different line parameters to determine whether the waves or flows could cause these oscillations to improve the current understanding on the nature of these disturbances.Comment: 12 pages, 6 figures. Accepted for publication in RA

    On Interval-Valued Intuitionistic Fuzzy Hyper BCK-Ideals of Hyper BCK Algebras

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    In this paper, we apply the concept of an interval-valued intuitionistic fuzzy set to hyper BCK-ideals in hyper BCK-algebras. The notion of an interval-valued intuitionistic fuzzification of (strong, weak, s-weak) hyper BCK-ideals is introduced, and related properties are investigated. Characterizations of an interval-valued intuitionistic fuzzification of hyper BCK-ideals are established

    X-Ray K-Absorption Studies of Some Cu(II) Complexes

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    Geometric Mechanics of Contact-Switching Systems

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    Discrete and periodic contact switching is a key characteristic of steady state legged locomotion. This paper introduces a framework for modeling and analyzing this contact-switching behavior through the framework of geometric mechanics on a toy robot model that can make continuous limb swings and discrete contact switches. The kinematics of this model forms a hybrid shape space and by extending the generalized Stokes' theorem to compute discrete curvature functions called stratified panels, we determine average locomotion generated by gaits spanning multiple contact modes. Using this tool, we also demonstrate the ability to optimize gaits based on system's locomotion constraints and perform gait reduction on a complex gait spanning multiple contact modes to highlight the scalability to multilegged systems.Comment: 6 pages, 7 figures, and link to associated video: https://drive.google.com/file/d/12Sgl0R1oDLDWRrqlwwAt3JR2Gc3rEB4T/view?usp=sharin

    Propellant Grade Hydrazine in Mono/Bi-propellant Thrusters: Preparation and Performance Evaluation

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    Propellant grade hydrazine was prepared with 64 per cent yield and 95.5 per cent purity. Purity of the propellant grade hydrazine was determined using wet chemical, gas chromatographic (GC) and eudiometric methods. It was observed that the compositions containing blends of hydrazine-methyl alcohol-ammonium nitrate and hydrazine-methyl alcohol-ammonium perchlorate were not found to be frozen even after cooling to -65 °C for 30 minutes. Mono and bi-propellant thrusters were designed and developed to demonstrate the performance of prepared propellant grade hydrazine as a promising rocket fuel. Five static tests with 22 N thruster and one static test with 1 N thruster were performed successfully in mono-propellant mode. The hurdles of chamber pressure oscillations were overcome by compact packing of the catalyst. The desired decomposition and chamber pressure were achieved. One static test was performed successfully with 60 N bi-propellant thruster. The desired chamber pressure and thrust were achieved. The combustion was smooth and C* achieved was higher than that of UH-25, N2O4 combination. The performance of prepared propellant grade hydrazine shows it as a promising rocket fuels.Defence Science Journal, Vol. 65, No. 1, January 2015, pp.31-38, DOI:http://dx.doi.org/10.14429/dsj.65.798

    Beam Switching Cylindrical Array Antenna System for Communication

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    The beam switching cylindrical array, which is a unique system, has been designed and developed to cover 360° in azimuth plane by generating 16 beams with specified elevation coverage.In this design, the concept of fast aperture selection (4 x 4) in microseconds from the total cylindrical array has been realised successfully to meet the requirement of point-to-multipoint communication. The components of the array, viz., radiating elements, powder dividers, switches, etc., are designed in printed circuit type, and hence, objectives of lightweight and ease of reproducibility are achieved. The lightweight of the array makes it accessible for easy mounting at a specified height for achieving longer communication range. Finally, a low-loss radome is incorporated to protect the array from environmental conditions. The various parameters, viz., return loss, gain, and switched-beam radiation patterns were measured over a bandwidth of 300 MHz in L- band and typical measured results are presented in this paper

    Lightweight CNN Models for Product Defect Detection with Edge Computing in Manufacturing Industries

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    Detecting product defects is one of the manufacturing industry's most essential processes in quality control. Human visual inspection for product defects is the traditional method employed in the industry. Nevertheless, it can be laborious, prone to human mistakes, and unreliable. Deep Learning-based Convolution Neural Networks (CNN) has been extensively used in fully automating product defect detection systems. However, real-time edge devices installed at the manufacturing site generally have limited computing capability and cannot run different CNN models. A lightweight CNN model is adopted in this scenario to find a balance between defect detection, model training time, memory consumption, computing time and efficiency. This work provides lightweight CNN models with transfer learning for product defect detection on fabric, surface, and casting datasets. We deployed the trained model to the NVIDIA Jetson Nano-kit edge device for detection speed with better simulation results in terms of accuracy, sensitivity rate, specificity rate, and F1 measure in the workplace context of the Manufacturing Industries

    Time-dependent suppression of oscillatory power in evolving solar magnetic fields

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    Oscillation amplitudes are generally smaller within magnetically active regions like sunspots and plage when compared to their surroundings. Such magnetic features, when viewed in spatially resolved power maps, appear as regions of suppressed power due to reductions in the oscillation amplitudes. Employing high spatial- and temporal-resolution observations from the Dunn Solar Telescope (DST) in New Mexico, we study the power suppression in a region of evolving magnetic fields adjacent to a pore. By utilizing wavelet analysis, we study for the first time how the oscillatory properties in this region change as the magnetic field evolves with time. Image sequences taken in the blue continuum, G-band, Ca ii K, and Hα filters were used in this study. It is observed that the suppression found in the chromosphere occupies a relatively larger area, confirming previous findings. Also, the suppression is extended to structures directly connected to the magnetic region, and is found to get enhanced as the magnetic field strength increased with time. The dependence of the suppression on the magnetic field strength is greater at longer periods and higher formation heights. Furthermore, the dominant periodicity in the chromosphere was found to be anti-correlated with increases in the magnetic field strength
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