Power system harmonics estimation using different signal processing techniques

Harmonics have been available for quite a while and its presence shapes the execution of a power system. Consequently, harmonics estimation is of principal vitality while analyzing the power system. Emulating the beginning of harmonics, different filters have been formulated to attain an ideal control methodology for constant rejection. This thesis acquaints different algorithms to dissect harmonics in the power system. The target is to estimate the voltage magnitude and phase plot of the power system in the proximity of noise by using various estimation approaches. This thesis has centered the consideration towards the investigation of Kalman filter (KF), Recursive Least squares (RLS), least mean square (LMS) and Variable leaky least mean square (VLLMS) based filter for estimation of harmonics. For a test signal KF, RLS, LMS and VLLMS based calculations have been examined and the results have been looked at. The several algorithms are compared for various signals to noise ratio. The SNR used here are 40 dB, 30dB and 20dB. The proposed estimation methodologies are implemented on a typical power system signal acquired from mechanical burden embodying power electronic converters and arc furnaces

EFFECT OFCO-ADMINISTRATION OF EMBLICA OFFICINALIS AND AEGLE MARMELOS EXTRACTS FOR ANTIOXIDANT AND ANTIDIABETIC ACTIVITY

Objective: The objective of the present study was to develop an HPLC analytical method and to perform in vivo study of Emblica officinalis and Aegle marmelos extracts for antioxidant and antidiabetic activity. Methods: The phytochemical analyses, total phenolic content (TPC), TLC, DPPH assay were performed for freeze-dried Emblica officinalis fruits aqueous extract (EOFAE) and Aegle marmelos leaves ethyl acetate extract (AMLEAE). The active constituents present in both extracts were estimated by using HPLC system having Hibar® C18 column [250 x4.6 mm, 5 µm] and UV detector (264 nm). A gradient mobile phase (acetonitrile and water with 0.1% trifluoroacetic acid) was used at a flow rate of 0.8 ml/min. In vivo antioxidant, antidiabetic activity of both extracts was conducted on male albino Wistar rats for 21 d in streptozotocin-induced diabetic rats (42 rats; n=6). The antidiabetic activity was measured by blood glucose level and biochemical parameters i.e. total cholesterol, triglycerides and total protein. Oxidative stress was measured by antioxidant biomarkers i.e. SOD, GSH, lipid peroxidation by thiobarbituric acid reactive substances method on the liver of the experimental rat. Results: Tannins, saponins, carbohydrate, glycosides are found in EOFAE; coumarins and flavonoids are found in AMLEAE and quinones, phenols are present in both extracts. The values of TPC present in standard gallic acid, EOFAE and AMLEAE were found to be 485.7, 315.6, 300.7 mgGAE/g, respectively. Rf values obtained by TLC of EOFAE and AMLEAE were found to be 0.41 and 0.50, respectively. The values of % inhibition shown by EOFAE and AMLEAE in DPPH assay were found to be 97.8%±2 and 95.2%±2, respectively. The values of retention time of EOFAE and AMLEAE by HPLC analysis were found to be 4.59 and 5.28 min, respectively. Histopathological examination of the liver was revealed that low dose EOAM (containing of EOFAE 250+AMLEAE 250 mg/kg body weight) administered once a daily for 21 d showed significant activity (P˂0.001) with biochemical parameters and antioxidant biomarkers. Conclusion: The present study showed that the EOFAE and AMLEAE treated group III with (EOAM) low dose of 500 mg/kg body weight has potent antioxidant and antidiabetic activity

Evaluating the effect of preoperative oral gabapentin on postoperative pain in patients receiving spinal anaesthesia for lower limb surgery

Background: Gabapentin has been used successfully as a non-opioid analgesic adjuvant for postoperative pain management. We hypothesised that gabapentin might be a useful adjuvant for postoperative analgesia in patients undergoing lower extremity surgery under subarachnoid block. Method: Ninety male patients undergoing lower extremity surgery under subarachnoid block were randomly divided into three groups. Group I (n = 30) patients received oral gabapentin 1 200 mg one hour prior to surgery. Group II (n = 30) patients received oral gabapentin 600 mg one hour prior to surgery. Group III (n = 30) patients received an oral placebo one hour prior to surgery. Lumbar puncture was done with 23G Quincke’s spinal needle and 2.5 mL of 0.5% heavy bupivacaine was administered intrathecally. Patients were monitored at 0, 1, 3, 5, 8, 12 and 24 hours for assessment of pain and side effects. Patients having pain scores ≥5 received rescue analgesia in the form of intravenous tramadol 0.5 mg.kg-1. If the pain score persisted at ≥5 after ten minutes, 0.25 mg.kg-1 tramadol was repeated. Results: Pain scores at zero hour were statistically significantly lower in patients receiving 1 200 mg of gabapentin (group I) when compared with the other two groups. The total rescue analgesia (tramadol) requirement over the study period was also at the minimum in patients receiving 1 200 mg of gabapentin as compared to patients receiving 600 mg of gabapentin or placebo. However, sedation scores were significantly higher in patients receiving gabapentin 1 200 mg or 600 mg than placebo. Conclusion: Preoperative gabapentin, when administered one hour prior to surgery in a dose of 1 200 mg, decreases postoperative pain scores at zero hour and the rescue analgesia requirement significantly over a period of 24 hours in patients undergoing lower limb surgery under spinal anaesthesia.Keywords: gabapentin; postoperative; pain; rescue analgesi

Underwater Optical Instrumentation

The paper presents a brief review of instrumentation necessary for carrying out in-situ light associated measurements in sea water. Recent developments in this area of instrumentation have been brought out. Practical significance of various parameters measured by these instruments has also been highlighted

Effect of magnetic field on the phase transition in a dusty plasma

The formation of self-consistent crystalline structure is a well-known phenomenon in complex plasmas. In most experiments the pressure and rf power are the main controlling parameters in determining the phase of the system. We have studied the effect of externally applied magnetic field on the configuration of plasma crystals, suspended in the sheath of a radio-frequency discharge using the Magnetized Dusty Plasma Experiment (MDPX) device. Experiments are performed at a fixed pressure and rf power where a crystalline structure is formed within a confining ring. The magnetic field is then increased from 0 to 1.28 T. We report on the breakdown of the crystalline structure with increasing magnetic field. The magnetic field affects the dynamics of the plasma particles and first leads to a rotation of the crystal. At higher magnetic field, there is a radial variation (shear) in the angular velocity of the moving particles which we believe leads to the melting of the crystal. This melting is confirmed by evaluating the variation of the pair correlation function as a function of magnetic field.Comment: 9 pages, 5 figure

TSUNAMIGENIC SOURCES IN THE INDIAN OCEAN

Based on an assessment of the repeat periods of great earthquakes from past seismicity, convergence rates and paleoseismological results, possible future source zones of tsunami generating earthquakes in the Indian Ocean (possible seismic gap areas) are identified along subduction zones and zones of compression. Central Sumatra, Java, Makran coast, Indus Delta, Kutch-Saurashtra, Bangladesh and southern Myanmar are identified as possible source zones of earthquakes in near future which might cause tsunamis in the Indian Ocean, and in particular, that could affect India. The Sunda Arc (covering Sumatra and Java) subduction zone, situated on the eastern side of the Indian Ocean, is one of the most active plate margins in the world that generates frequent great earthquakes, volcanic eruptions and tsunamis. The Andaman- Nicobar group of islands is also a seismically active zone that generates frequent earthquakes. However, northern Sumatra and Andaman-Nicobar regions are assessed to be probably free from great earthquakes (M!8.0) for a few decades due to occurrence of 2004 Mw 9.3 and 2005 Mw 8.7 earthquakes. The Krakatau volcanic eruptions have caused large tsunamis in the past. This volcano and a few others situated on the ocean bed can cause large tsunamis in the future. List of past tsunamis generated due to earthquakes/volcanic eruptions that affected the Indian region and vicinity in the Indian Ocean are also presented

Complete Agenesis of the Dorsal Pancreas: Case Report with Imaging Findings and Review of the Literature

No Abstrac

Magnetotransport of SrIrO 3 -based heterostructures

Transition-metal oxide (TMO) based heterostructures provide fertile playground to explore or functionalize novel quantum materials. In this regard, the combination of 3d and 5d TMOs have gained special interest because of the simultaneous appearance of strong spin-orbit coupling and electron correlation at the interface of those heterostructures. Artificial breaking of the inversion symmetry in heterostructures may also result in a distinct interfacial Dzyaloshinskii- Moriya interaction (DMI) and the formation of non-collinear magnetic spin structures in case of magnetic TMOs. Among the 5d TMOs, SrIrO3 (SIO) has gained significant attention because of its large spin-orbit coupling and the semi-metallic ground state, which are highly susceptible to structural distortions. Here, we report on the preparation and the characterisation of structural, electronic and magnetic properties of epitaxial heterostructures consisting of the 5d TMO SIO and the 3d antiferromagnetic insulator LaFeO3