177 research outputs found

    Modelling And Simulation Of Lossless Damping Reduction By Vector Controlled Ac Motor Drive With An Efficient Lc Filter

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    In this paper Active damping technique isused to damp out the unwanted resonant frequencyoscillations and proposed for lossless damping of vectorcontrolledac drives with an efficient LC-Filter.  Thispaper mainly concentrated on protection of Inductionmotor and Synchronous motor under any balanced orunbalanced load conditions and this proposed techniqueis simulated with the combination of Voltage SourceInverter (VSI), LC Filter and AC Drives. However, theLC-Filter created unwanted oscillations due to internalresistance at system resonant frequency. This resistancedrop is emulated by controlling terminal voltage. Theproposed technique neither affects the dynamicresponse of the drive nor changes the design of thestandard vector control loops. This proposed techniqueis carried out in three phase domain for better accuracyof control. This paper has been implemented andsimulated by using MATLAB/ SIMULINK 7.8 (R2009a)version

    Generation of Groundwater Quality Index Map: A Case Study

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    Reliance on groundwater has been rapidly increasing, especially in the arid and semiarid regions, resulting in its overexploitation leading to deterioration of quality. Kurmapalli Vagu basin of Andhra Pradesh, a semi-critical region with respect to the stage of groundwater development is a good example. Its monitoring and assessment is imperative for devising preventive measures against health hazards. Groundwater samples from twenty five locations were collected and analyzed for various physico-chemical parameters in terms of Water Quality Index (WQI) to determine its suitability for drinking purposes. Seven locations were found to have WQI value within the limits. High values of WQI were mostly due to high content of Fluorides. WQI Contour map was generated to study spatial distribution of quality of groundwater. Suitable remedial measures and groundwater augmenting structures are proposed in the study area to improve the quality of groundwater. Keywords: Groundwater, WQI, Fluorosis, Groundwater augmenting structures

    Pharmacognostic study of Argyreia pilosa stem

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    Background and objectives: Argyreia pilosa (Convolvulaceae) has been utilized for many aliments in the conventional system ethnomedicinally; most significantly against sexually transmitted diseases, skin troubles, diabetes, rheumatism, cough, and quinsy. The key challenge experienced in the standardization of herbal drugs is the correct identification of the plant source. Thus, setting up quality control parameters by means of pharmacognostic and phytochemical analysis which assures the purity, safety, and efficiency of A. pilosa is necessary. The current research was conducted to assess the pharmacognostic characteristics including macroscopic, microscopic, phytochemical and physicochemical parameters of the stems of A. pilosa. Methods: Micro as well as macroscopic characteristics were investigated. Physicochemical parameters had been done by implementing WHO suggested parameters; preliminary phytochemical and fluorescent evaluation of stem was executed for appropriate identification and standardization.  Results: The color, shape, size, odor and surface characteristics were reported from the stem and powdered stem material of A. pilosa. Light microscope images of cross section and powdered stem revealed the presence of phloem fibers, multicellular uniseriate trichomes, sclerides, lignified xylem fibers, xylem vessels, parenchyma cells and medullary rays. Phytochemical testing confirmed the presence of flavonoids, alkaloids, tannins, phenols, steroids, fixed oils, fats, acid compounds, glycosides, amino acids, and proteins. Physicochemical parameters such as moisture content, ash value, extractive value and fluorescent behavior of stem powder have also been established. Conclusion: The current research would be useful in order to supplement the information regarding to standardization, identity and in performing additional explorations in Ayurvedic system of medicine

    Simulation of SVPWM Based Multivariable Control Method for a DFIG Wind Energy System

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    This paper deals with a variable speed device toproduce electrical energy on a power network based on adoubly-fed induction machine used in generating mode(DFIG) in wind energy system by using SVPWM powertransfer matrix. This paper presents a modeling and controlapproach which uses instantaneous real and reactive powerinstead of dq components of currents in a vector controlscheme. The main features of the proposed model comparedto conventional models in the dq frame of reference arerobustness and simplicity of realization. The sequential loopclosing technique is adopted to design a multivariable controlsystem including six compensators for a DFIG wind energysystem to capture the maximum wind power and to inject therequired reactive power to the generator. In this paperSVPWM method is used for better controlling of converters.It also provides fault ride through method to protect theconverter during a fault. The time-domain simulation of thestudy system is presented by using MATLAB Simulink to testthe system robustness, to validate the proposed model and toshow the enhanced tracking capability

    Flecainide challenge test: Predictors of unmasking of type 1 Brugada ECG pattern among those with non-type 1 Brugada ECG pattern

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    AbstractBackgroundMany subjects in community have non-type 1 Brugada pattern ECG with atypical symptoms, relevance of which is not clear. Provocative tests to unmask type 1 Brugada pattern in these patients would help in diagnosing Brugada Syndrome. However sensitivity and specificity of provocating drugs are variable.MethodsWe studied 29 patients referred to our institute with clinical presentation suggestive but not diagnostic of Brugada or with non-Type 1 Brugada pattern ECG. Flecainide Challenge Test (FCT) was done in these patients (IV Flecainide test in 4 patients and Oral Flecainide in 25 patients). Resting 12-lead ECG with standard precordial leads and ECG with precordial leads placed 1 Intercostal space above were performed after flecainide administration every 5 min for first 30 min and every 30 min thereafter until ECG became normal or upto 6 h. The positivity was defined as inducible Type 1 Brugada pattern in atleast 2 right sided leads.ResultMedian age was 35(range = 5–65) years. In 16 (55%) patients the Type 1 Brugada pattern was unmasked. There were no episodes of major AV block, atrial or ventricular tachyarrhythmia. Three groups were considered for analysis: Group 1(n = 9) – FCT Positive among patients with non-type 1 Brugada ECG pattern, Group 2(n = 4) – FCT Negative among the patients with non-type 1 Brugada ECG pattern, and Group 3(n = 7) – FCT Positive among patients with no spontaneous Brugada ECG pattern. Binary logistic regression analysis found that family h/o SCD was predictive of FCT positivity in Group 1 (Odd’s ratio 21, 95% Confidence interval 1.04 to 698.83, p = 0.004).ConclusionOral flecainide is useful and safe for unmasking of Type I Brugada pattern. In our study, among the many variables studied, family history of sudden cardiac death was the only predictor of flecainide test positivity among those with non-Type 1 Brugada pattern

    Prediction of outcomes in acute exacerbation of COPD with DECAF score and BAP 65 score in a rural population

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    Background: Prognostic research in exacerbations of chronic obstructive pulmonary disease (COPD) requiring hospitalization has been limited and there appears to be little common ground between predictors of mortality in stable disease and during AECOPD. Furthermore, none of the prognostic tools developed in stable disease have been tested on hospitalised patients, and most require clinical measurements not routinely available at hospital admission. This study intends to test dyspnoea, eosinopenia, consolidation, acidemia, and atrial fibrillation (DECAF) and biological assessment profile (BAP) 65 Scores on Indian patients in a tertiary care set up and validate the same to be used as a routine and effective score in predicting the outcome in AECOPD.  Methods: Hospital based prospective observational study was carried out in 100 patients with AECOPD who was present to general medicine. DECAF and BAP-65 Scores were calculated. Data was analyzed using SPSS 22 version software.Results: In our study both DECAF score and BAP‑65 score performed equally well for prediction of need for Mechanical Ventilation. The AUROC for need for Mechanical Ventilation was 0.77 (95% CI=0.67–0.84) for DECAF score and 0.77 (95% CI=0.67–0.85) for BAP‑65 score. The AUROC for prediction of mortality for DECAF score was 0.83 (95% confidence interval [CI]=0.74–0.89) and for BAP‑65 score was 0.79 (95% CI=0.69–0.86).Conclusions: DECAF and BAP-65 are good and also equal in predicting mortality as well as need for mechanical ventilation. Both scores can be easily applicable in AECOPD patients, so that death during hospitalization for AECOPD and need for mechanical ventilation can be minimized.

    PAN SHARPENING USING RELATIVE SPECTRAL RESPONSE OF SENSOR FOR CARTOSAT-1 PAN AND RESOURCESAT LISS-4 MX DATA

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    Most of the Indian remote sensing systems, provide sensors with one high spatial resolution panchromatic (PAN) and several multispectral (MS) bands. An increasing number of applications, such as feature detection, change monitoring, and land cover classification, often demand the use of images with both high spatial and high spectral resolution. Image fusion or pan sharpening, is a technique to enhance the spatial resolution. The most significant problem in the traditional fusion methods is spectral distortion of fused images. The main reason for this being, the physical spectral characteristic of the sensors are not considered during the fusion process, resulting in undesirable effects such as modified spectral signatures resulting in classification errors and resolution over injection. For most earth resource satellites which provide both PAN and MS bands, in ideal condition, all MS bands would be well separated and would cover exactly the same wavelengths as the PAN band. Theoretically, the measured energy in the PAN band can be obtained with the summation of corresponding MS bands. As the measured energy in an individual channel is the sum of incoming radiation and relative spectral response: Lk&thinsp;=&thinsp;L(&lambda;)&thinsp;Rk(&lambda;); where &lambda; is the wavelength, the in-band radiance, L(&lambda;) at aperture spectral radiance and Rk(&lambda;) the peak-normalized spectral response. Therefore, the energy in PAN band can be estimated by defining weights as follows: Pan&thinsp;=&thinsp;wR&thinsp;R&thinsp;+&thinsp;wG&thinsp;G&thinsp;+&thinsp;wNIR NIR&thinsp;+ other; where Pan, G, R, NIR represent the radiance of individual spectral bands wG, wR, wNIR are the weights of corresponding MS bands and other for the influence of the spectral range which is missing from MS bands but still covered with the PAN band. In this paper, a novel spectral preservation fusion method for remotely sensed images using Cartosat-1 PAN and Resourcesat-Liss4 Mx data is presented by considering the physical characteristics of the sensors. It is based on the curvelet transform using relative spectral response (RSR) values of the sensor, improved in two parts: 1) the construction of PAN image using RSR values and the curvelet components, 2) the injection method of detail information. The performance and efficiency of the proposed method is compared with traditional IHS, wavelet based methods both visually and quantitatively. The results show that the proposed method preserves spatial details and minimize spectral distortion.</p

    Simultaneous solution of Kompaneets equation and Radiative Transfer equation in the photon energy range 1 - 125 KeV

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    Radiative transfer equation in plane parallel geometry and Kompaneets equation is solved simultaneously to obtain theoretical spectrum of 1-125 KeV photon energy range. Diffuse radiation field is calculated using time-independent radiative transfer equation in plane parallel geometry, which is developed using discrete space theory (DST) of radiative transfer in a homogeneous medium for different optical depths. We assumed free-free emission and absorption and emission due to electron gas to be operating in the medium. The three terms n,n2n, n^2 and (nxk)\displaystyle \bigg({\frac {\partial n}{\partial x_k}}\bigg) where nn is photon phase density and xk=(hνkTe)\displaystyle x_k= \bigg({\frac {h \nu} {k T_e}} \bigg) , in Kompaneets equation and those due to free-free emission are utilized to calculate the change in the photon phase density in a hot electron gas. Two types of incident radiation are considered: (1) isotropic radiation with the modified black body radiation IMBI^{MB} [1] and (2) anisotropic radiation which is angle dependent. The emergent radiation at τ=0\tau=0 and reflected radiation τ=τmax\tau=\tau_{max} are calculated by using the diffuse radiation from the medium. The emergent and reflected radiation contain the free-free emission and emission from the hot electron gas. Kompaneets equation gives the changes in photon phase densities in different types of media. Although the initial spectrum is angle dependent, the Kompaneets equation gives a spectrum which is angle independent after several Compton scattering times.Comment: 31 pages, 8 figures, Accepte

    Observations on impact of stunting on breeding performance of farmed rohu Labeo rohita (Hamilton, 1822)

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    Breeding performance of stunted rohu Labeo rohita (Hamilton, 1822) was compared with normally reared rohu. Randomly selected stunted and normal fishes were tagged and reared together in a single earthen pond for broodstock development. Both groups exhibited growth enhancement during the broodstock development period, though normal fishes were found larger in size than the stunted fishes, after the rearing period. Gonadosomatic Index (GSI) of female fishes indicated a similar trend of ovary growth in both the group

    Potential and Challenges of Rainfed Farming in India

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    India ranks first in rainfed agriculture globally in both area (86 Mha) and the value of produce. Rainfed regions in India contribute substantially toward food grain production including 44% of rice, 87% of coarse cereals (sorghum (Sorghum bicolor), pearl millet (Pennisetum glaucum), maize (Zea mays)), and 85% of food legumes, 72% of oilseeds, 65% of cotton, and 90% of minor millets. Overall, the rainfed areas produce 40% of the food grains, support two-thirds of the livestock population, and are critical to food security, equity, and sustainability..
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