2,417 research outputs found

    The dynamics and control of large flexible space structures-IV

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    The effects of solar radiation pressure as the main environmental disturbance torque were incorporated into the model of the rigid orbiting shallow shell and computer simulation results indicate that within the linear range the rigid modal amplitudes are excited in proportion to the area to mass ratio. The effect of higher order terms in the gravity-gradient torque expressions previously neglected was evaluated and found to be negligible for the size structures under consideration. A graph theory approach was employed for calculating the eigenvalues of a large flexible system by reducing the system (stiffness) matrix to lower ordered submatrices. The related reachability matrix and term rank concepts are used to verify controllability and can be more effective than the alternate numerical rank tests. Control laws were developed for the shape and orientation control of the orbiting flexible shallow shell and numerical results presented

    Quantitative precipitation forecasting over Narmada catchment

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    Quantitative precipitation forecasting (QPF) has been attempted over the Narmada Catchment following a statistical approach. The catchment has been divided into five sub-regions for the development of QPF models with a maximum lead-time of 24 hours. For this purpose the data of daily rainfall from 56 raingauge stations, twice daily observations on different surface meteorological parameters from 28 meteorological observatories and upper air data from 11 aerological stations for the nine monsoon seasons of 1972-1980 have been utilized. The horizontal divergence, relative vorticity, vertical velocity and moisture divergence are computed using the kinematic method at different pressure levels and used as independent variables along with the rainfall and surface meteorological parameters. Multiple linear regression equations have been developed using the stepwise procedure separately with actual and square root and log-transformed rainfall using 8-year data (1972-1979). When these equations were verified with an independent data for the monsoon season of 1980, it was found that the transformed rainfall equations fared much better compared to the actual rainfall equations. The performance of the forecasts of QPF model compared to the climatological and persistence forecasts has been assessed by computing the verification scores using the forecasts for the monsoon season of 1980

    Taxol-DNA interactions: fluorescence and CD studies of DNA groove binding properties of taxol

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    Taxol is perhaps the most successful drug used for the treatment of various cancers. Comprehensive literature accumulated on therapeutics of the drug has indicated numerous side effects. In this paper, by use of fluorescence spectroscopy, it is shown that taxol binds to DNA with an affinity constant (Ka) of 1.08×107 M-1. This binding is accompanied by a large 'red edge excitation shift' (REES) of fluorescence emission maximum in taxol-DNA complex. The results point to an interaction of taxol with its core eight-membered ring in the DNA groove and the three phenyl rings projecting away from the DNA. The drug encompasses about two base pairs of DNA upon binding to it. Systematic studies with taxol analogues confirms such a mode of binding. These interesting findings on hitherto unknown taxol-DNA interactions may have clinical implications in view of its large number of side effects and pharmacokinetics

    Bidirectional Growth based Mining and Cyclic Behaviour Analysis of Web Sequential Patterns

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    Web sequential patterns are important for analyzing and understanding users behaviour to improve the quality of service offered by the World Wide Web. Web Prefetching is one such technique that utilizes prefetching rules derived through Cyclic Model Analysis of the mined Web sequential patterns. The more accurate the prediction and more satisfying the results of prefetching if we use a highly efficient and scalable mining technique such as the Bidirectional Growth based Directed Acyclic Graph. In this paper, we propose a novel algorithm called Bidirectional Growth based mining Cyclic behavior Analysis of web sequential Patterns (BGCAP) that effectively combines these strategies to generate prefetching rules in the form of 2-sequence patterns with Periodicity and threshold of Cyclic Behaviour that can be utilized to effectively prefetch Web pages, thus reducing the users perceived latency. As BGCAP is based on Bidirectional pattern growth, it performs only (log n+1) levels of recursion for mining n Web sequential patterns. Our experimental results show that prefetching rules generated using BGCAP is 5-10 percent faster for different data sizes and 10-15% faster for a fixed data size than TD-Mine. In addition, BGCAP generates about 5-15 percent more prefetching rules than TD-Mine.Comment: 19 page

    Asymmetric Squares as Standing Waves in Rayleigh-Benard Convection

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    Possibility of asymmetric square convection is investigated numerically using a few mode Lorenz-like model for thermal convection in Boussinesq fluids confined between two stress free and conducting flat boundaries. For relatively large value of Rayleigh number, the stationary rolls become unstable and asymmetric squares appear as standing waves at the onset of secondary instability. Asymmetric squares, two dimensional rolls and again asymmetric squares with their corners shifted by half a wavelength form a stable limit cycle.Comment: 8 pages, 7 figure

    ANTIOXIDANT STUDIES OF ONE AYURVEDIC MEDICINE ASWAGANDHARISHTAM

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    Objective: The present study deals with the antioxidant study of one Ayurvedic medicine Aswagandhrishtam by three different methods, namely reducing power, 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays.Methods: Aswagandharishtam, which is a liquid medicine, was taken as such at various concentrations for all the three assays.Results: The results show that Aswagandharistam has good antioxidant potential when compared with ascorbic acid as standard. The IC50 values of reducing power assay were 250.142, that of DPPH were 103.607, and of ABTS assay were 197.79 as compared with that of ascorbic acid being 19.59.Conclusion: All the three assays indicated that Aswagandharishtam showed very good antioxidant results

    Online proctoring with face analysis and object recognition using Yolo

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    To guarantee academic integrity, the spread of online education and tests has prompted the creation of secure and dependable online proctoring solutions. We present a comprehensive real-time online proctoring system in this study that uses gaze movement analysis, facial aspect ratio assessment, and mouth opening status detection to detect probable cheating behaviours during remote tests. Furthermore, the system uses the You Only Look Once (YOLO) algorithm to detect forbidden goods like as phones and books within the examination area.The gaze movement analysis module monitors students' eye movements during the examination using computer vision techniques such as eye tracking algorithms built in Scipy. The technology may detect instances of prolonged off-screen gazing by analysing gaze patterns, highlighting potential attempts to access unauthorised materials.The facial aspect ratio analysis component calculates the aspect ratio of major facial features using facial landmarks. This method aids in detecting anomalous head motions or changes from conventional facial expressions that may suggest dishonesty.Furthermore, the proctoring system employs mouth opening status detection, which is accomplished through the use of deep learning algorithms, to identify instances of verbal communication or whispering throughout the exam. Our method incorporates the YOLO object detection technique, in addition to gaze and facial analysis, to recognise phones and books in the examination setting. Using a pre-trained YOLO model, the system can detect and flag any unauthorised items in the area of the students. Using a broad dataset of simulated examination scenarios and real-world proctoring instances, we assess the performance of the proposed online proctoring system. The findings illustrate the system's accuracy and effectiveness in detecting potential instances of academic cheating, giving teachers vital insights into student behaviour during remote tests. Finally, our study introduces a novel technique to real-time online proctoring that incorporates gaze movement analysis, face aspect ratio assessment, mouth opening status detection, and YOLO-based object detection. This multifaceted approach helps to improve the integrity and security of remote exams in the digital education era

    Designing multi-period supply chain network considering risk and emission: a multi-objective approach

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    This research formulates a multi-objective problem (MOP) for supply chain network (SCN) design by incorporating the issues of social relationship, carbon emissions, and supply chain risks such as disruption and opportunism. The proposed MOP includes three conflicting objectives: maximization of total profit, minimization of supply disruption and opportunism risks, and minimization of carbon emission considering a number of supply chain constraints. Furthermore, this research analyses the effect of social relationship levels between different tiers of SCN on the profitability, risk, and emission over the time. In this regard, we focus on responding to the following questions. (1) How does the evolving social relationship affect the objectives of the supply chain (SC)? (2) How do the upstream firms’ relationships affect the relationships of downstream firms, and how these relationships influence the objectives of the SC? (3) How does the supply disruption risk interact with the opportunism risk through supply chain relationships, and how these risks affect the objectives of the SC? (4) How do these three conflicting objectives trade-off? A Pareto-based multi-objective evolutionary algorithm–non-dominated sorting genetic algorithm-II (NSGA-II) has been employed to solve the presented problem. In order to improve the quality of solutions, tuning parameters of the NSGA-II are modulated using Taguchi approach. An illustrative example is presented to manifest the capability of the model and the algorithm. The results obtained evince the robust performance of the proposed MOP

    SOLUBILITY ENHANCEMENT OF NORFLOXACIN BY HYDROTROPY TECHNIQUE

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    The objective of this study is to improve the solubility of poorly water soluble anti-bacterial drug Norfloxacin by hydrotropic solubilization technique. For the present study sodium benzoate was used as hydrotropic agent. By using this hydrotropic agent as water soluble carrier, hydrotropic solid dispersions of Norfloxacin were prepared.in 1:1, 1:2, 1:3 and 1:4 ratios (drug: hydrotropic agent). Equilibrium solubilization of pure drug and hydrotropic solid dispersions of Norfloxacin in distilled water by excess solute method and solubility enhancement ratios were calculated by measuring the absorbance of the solutions at 274.80 nm using UV spectrophotometer. The hydrotropic agent did not interfere in analysis. The results showed that there was an increase in the solubility of Norfloxacin with hydrotropic solid dispersions compared to pure drug in distilled water. There was 9.56 fold enhancement in aqueous solubility of Norfloxacin with hydrotropic solid dispersion of 1:4 ratio compared to 1:1 (6.29), 1:2 (7.09) and 1:3 (8.59) ratios
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