Fuzzy controlled modified reduced switch converter for switched reluctance motor under dynamic loading

In this paper, modified reduced switch converter topology is used to drive 8/6 pole, 7500 W switched reluctance motor (SRM) with an electric vehicle (EV) load. Fuzzy logic control (FLC) is developed for the modified converter topology and its performance is compared with the proportional integral (PI) controller. Analytical equations, switching pulses and different mode of operation are presented for modified reduced switch converter using double phase magnetization scheme. The converter topology adopts a modified switching sequence i.e., magnetization then freewheeling before demagnetization. It offers lesser torque ripples, reduced phase current and need only four switches for a 4-phase SRM drive. Modified reduced switch converter is simulated in MATLAB-simulation to investigate and compare the steady state waveforms and transient speed response of the PI and FLC. Torque ripple in modified converter is 50% less than the classical converter. Peak overshoot and settling time performance of FLC is superior as compared to PI, when applied to modified converter with EV loading

Antioxidants of Phyllanthus emblica

Phyllanthus emblica L. (amla) has been used in Ayurveda as a potent rasayan for treatment of hepatic disorders. Most of the pharmacological studies, however, are largely focused on PE fruit, while the rest of the parts of PE, particularly, bark, remain underinvestigated. Therefore, we aimed to investigate the protective effect of the hydroalcoholic extract of Phyllanthus emblica bark (PEE) in ethanol-induced hepatotoxicity model in rats. Total phenolic, flavonoid, and tannin content and in vitro antioxidant activities were determined by using H2O2 scavenging and ABTS decolorization assays. Our results showed that PEE was rich in total phenols (99.523±1.91 mg GAE/g), total flavonoids (389.33±1.25 mg quercetin hydrate/g), and total tannins (310±0.21 mg catechin/g), which clearly support its strong antioxidant potential. HPTLC-based quantitative analysis revealed the presence of the potent antioxidants gallic acid (25.05 mg/g) and ellagic acid (13.31 mg/g). Moreover, one-month PEE treatment (500 and 1000 mg/kg, p.o.) followed by 30-day 70% ethanol (10 mL/kg) administration showed hepatoprotection as evidenced by significant restoration of ALT (p<0.01), AST (p<0.001), ALP (p<0.05), and TP (p<0.001) and further confirmed by liver histopathology. PEE-mediated hepatoprotection could be due to its free radical scavenging and antioxidant activity that may be ascribed to its antioxidant components, namely, ellagic acid and gallic acid. Thus, the results of the present study support the therapeutic claims made in Ayurveda about Phyllanthus emblica

A preliminary study on perioperative hemostatic effect of spray dried powder of <i>Chromolaena odorata</i> leaf extract

547-555Accidents or surgery often cause internal haemorrhage in liver and arteries which may lead to patient morbidity and mortality. The current hemostatic agents used for treatment like collagen, oxidized cellulose, and chitosan suffer from side effects which include infection, inflammation and even sepsis. In the present study, we studied the spray dried powder (SDP) of the aqueous extract of the leaves of Chromolaena odorata (L.) R.M.King & H.Rob., commonly known as Siam weed or Common floss flower and also Christmas bush, for its hemostatic efficacy in two experimental models of surgery. Firstly, the SDP was screened through standard pharmacognostical parameters, and a part of the liver was lacerated in rats and femoral artery was transected in rabbits to assess the blood loss in pre-weighed gauze with and without treatment. In the liver laceration model, an effective blood loss reduction of 54.30 % was observed with oral administration of SDP 7 days prior to surgery. Similarly, application of SDP at the site of artery transection caused 70.36% reduction in blood loss as compared to the control rabbit artery. The results suggest that oral delivery and/or application of SDP of C. odorata by formulating it in a suitable drug delivery tool could minimize perioperative bleeding in hepatic and arterial tissue and improve recovery

Improving the IEEE 802.11 MAC layer handoff latency to support multimedia traffic

Multimedia applications can be offered to mobile users on the IEEE 802.11 WLAN, if their bandwidth, delay and jitter requirements are met, even in the presence of handoffs. Applications such as VoIP require a delay of less than 150 msecs and packet loss less than 3%. Studies have shown that the latencies achieved by existing handoff implementations can exceed 200 ms and packet loss can exceed 10%. Thus, there is a need for fast handoff solutions, that can meet multimedia traffic requirements. We propose a mechanism for layer-2 fast handoff with the help of background scanning, restricted channel set and preauthentication which does not require any code modification at the access points. The mechanism has been implemented in the MadWiFi wireless open source Linux drivers and tested in an indoor wireless environment. Results have shown that our mechanism achieves latency of less than 10 msec with negligible packet loss even in the presence of handoffs. Thus our mechanism makes mobile multimedia applications possible in IEEE 802.11 WLANs.© IEE

Improving the accuracy of wireless LAN based location determination systems using Kalman filter and multiple observers

Various RF based location determination systems have been proposed that use received signal strength fingerprints to identify locations. We implemented a Bayesian method for location determination in a WLAN testbed and were able to get about 80% accuracy of estimation with a precision of 2.5 meters. We proposed two mechanisms to improve this accuracy: 1) Kalman filtering to remove noise in received signal strength readings and 2) a technique which uses estimates from multiple observers to determine the location. Results from an IEEE 802.11b based implementation of the first method shows that Kalman filtering during the training phase can increase this accuracy to 90%. The multiple observer technique that uses received signal strength readings of the mobile device at the access point, also shows a similar increase in accuracy. Since the multiple observer technique requires more time and resources, we conclude that Kalman filtering is a more efficient and simple way to increase the accuracy of location determination.© IEE

Antioxidants of Phyllanthus emblica L. Bark Extract Provide Hepatoprotection against Ethanol-Induced Hepatic Damage: A Comparison with Silymarin

Phyllanthus emblica L. (amla) has been used in Ayurveda as a potent rasayan for treatment of hepatic disorders. Most of the pharmacological studies, however, are largely focused on PE fruit, while the rest of the parts of PE, particularly, bark, remain underinvestigated. Therefore, we aimed to investigate the protective effect of the hydroalcoholic extract of Phyllanthus emblica bark (PEE) in ethanol-induced hepatotoxicity model in rats. Total phenolic, flavonoid, and tannin content and in vitro antioxidant activities were determined by using H 2 O 2 scavenging and ABTS decolorization assays. Our results showed that PEE was rich in total phenols (99.523 ± 1.91 mg GAE/g), total flavonoids (389.33 ± 1.25 mg quercetin hydrate/g), and total tannins (310 ± 0.21 mg catechin/g), which clearly support its strong antioxidant potential. HPTLC-based quantitative analysis revealed the presence of the potent antioxidants gallic acid (25.05 mg/g) and ellagic acid (13.31 mg/g). Moreover, one-month PEE treatment (500 and 1000 mg/kg, p.o.) followed by 30-day 70% ethanol (10 mL/kg) administration showed hepatoprotection as evidenced by significant restoration of ALT ( &lt; 0.01), AST ( &lt; 0.001), ALP ( &lt; 0.05), and TP ( &lt; 0.001) and further confirmed by liver histopathology. PEE-mediated hepatoprotection could be due to its free radical scavenging and antioxidant activity that may be ascribed to its antioxidant components, namely, ellagic acid and gallic acid. Thus, the results of the present study support the therapeutic claims made in Ayurveda about Phyllanthus emblica