A novel technique for the measurement of liquid viscosity

A novel technique for the measurement of liquid viscosity is presented. In this technique, a disk was driven by a constant speed dc shunt motor in the test liquid. The change in the motor current measured the viscosity. The change in motor current was measured using an instrumentation amplifier and the viscosity of the liquid was measured in terms of output voltage. The temperature of the liquid was controlled using a peltier cooler/heater and was measured using an AD590 two-terminal integrated circuit temperature sensor. The viscosity of vegetable oils (groundnut, palm, sunflower, coconut) in the temperature range from 20 °C to 60 °C were determined. The results thus found were similar to the results obtained from a Redwood viscometer. This technique is useful to measure viscosity of liquids.     

A three-phase symmetrical multistage Voltage multiplier

A three-phase symmetrical Cockcroft-Walton (CW) multistage voltage multiplier (VM) is proposed. It consists of one smoothing column and six oscillating columns. The oscillating columns are connected to three-phase power through center-tap transformers. The capacitors of the smoothing column are charged six times per cycle by six oscillating columns and are discharged six times through the load, unlike the conventional symmetrical VM in which they are charged and discharged twice per cycle. The three-phase symmetrical structure completely eliminates the first five harmonic components of load-generated voltage ripple. Theoretical analysis indicates that the proposed three-phase symmetrical CW-VM has one-third the voltage ripple and voltage drop of the conventional single-phase symmetrical CW-VM. Experimental and simulation results of the proposed three-phase symmetrical CW-VM as well as of the conventional single-phase symmetrical CW-VM are presented. A comparison shows that the three-phase symmetrical CW-VM has significantly less voltage ripple, half the voltage drop, and a fourfold increase in output power over the conventional single-phase symmetrical CW-VM.     

Way forward in meeting energy challenges in Pakistan

In this review the energy potential of Pakistan from hydro, coal, wind, solar and nuclear sources has been discussed. The new projects that are being commissioned on coal, wind, solar, hydel and nuclear-based technologies have also been mentioned. The review has also explored the future prospects of the country’s energy requirements. Pakistan has potential to produce 100,000?MW of electricity from Thar coal for 20 years, 56,000?MW of hydroelectricity, 150,000?MW of wind energy and ～50,000?MW from solar sources. The coal-fired power generation is expected to 11,500?MW in period 2017–2019. The country is moving in the right direction to cater its energy needs. However, there is a need to find local and foreign investment in the country to meet high energy demands in the country in future.     

Effect of plasma treatment and electron beam radiations on the strength of nanofilled adhesive‐bonded joints

This investigation highlights the adhesion performance of carbon fiber‐ and glass fiber‐reinforced polyphenylene sulfide when joined by high‐performance neat epoxy adhesive and nanofilled epoxy adhesive. A significant increase in the surface energy of these materials is observed after the surface modification with atmospheric plasma treatment. An increase in surface roughness is observed after exposing the surface to plasma. Lap shear testing of untreated and plasma‐treated joints is carried out to correlate the improvement in adhesion properties with the joint strength. A considerable increase in joint strength is observed when the surfaces of these materials are modified by atmospheric pressure plasma. There is a further increase in joint strength when the composites are joined by nanofilled epoxy adhesive, and subsequent exposure to electron beam radiations results in minor increase in the joint strength. Finally, the fractured surfaces of the joints are examined and the analysis is performed. POLYM. ENG. SCI., 50:1505–1511, 2010. © 2010 Society of Plastics Engineers     

Fuzzy Self-tuning PID Controller for Speedtronic Governor Controlled Heavy Duty Gas Turbine Power Plants

Heavy duty gas turbine power plants may cause severe instability in grid connected operation under load fluctuations. To overcome such instability problems, an attempt has been made to develop proportional-integral-derivative controller for all the heavy duty gas turbine models with Speedtronic governor. Proportional-integral-derivative gains are tuned by Ziegler-Nichols and performance index methods and the step responses are obtained by using MATLAB/Simulink considering various droop settings. Simulation results of all the models reveal that the integral of squared error tuned proportional-integral-derivative controller provide better response. In order to improve the stability further, fuzzy self-tuning proportional-integral-derivative controller has been proposed in this article for all the heavy duty gas turbine models. On analyzing the simulation results, the proposed fuzzy self-tuning proportional-integral-derivative controller is found to be adaptive for all the heavy duty gas turbine models irrespective of the droop settings and yield better transient and steady state responses than Ziegler Nichols and Performance index methods.     

A New Distance Relaying Algorithm for Single-phase-to-ground Faults on Series-compensated Parallel Lines without the Parameter Requirement of Mutual Coupling and Series Capacitor Device

A new distance-relaying algorithm for single-phase-to-ground faults on series-compensated parallel transmission lines is proposed in this article. Fault impedance can be calculated using this algorithm without any parameters requirement of mutual coupling and series capacitor device (series capacitor/metal oxide arrestor/discharging gap). The series capacitor device is simplified as linearized impedance during faults. The parameters of mutual coupling and a series capacitor device can be used as variables in the fault loop equations. Real-time digital simulator tests show that the proposed distance-relaying algorithm can obtain more accurate results than traditional distance-relaying algorithms for series-compensated parallel transmission lines.     

Proteins and trypsin inhibitor activity of guar (Cyamopsis tetragonoloba L. Taub) seed

Proteins soluble in tris-acetate buffer (pH9.0) were fractionated by DEAE-cellulose, DEAE-Sephadex A-50 and Sephadex G-200 column chromatography. The purified proteins which contained 5–6% carbohydrate, had molecular weights of 125 900 and 22 390 amu. The high molecular weight fraction was homogeneous by polyacrylamide gel electrophoresis. Proteins extracted in phosphate buffer (0.1M , pH7.6) when subjected to Sephadex G-200 gel chromatography were resolved into three fractions, all of which showed considerable trypsin inhibitor activity. Germination for 3 days reduced the trypsin inhibitor activity of the seed by about 30%.     

Doxorubicin-loaded cholic acid-polyethyleneimine micelles for targeted delivery of antitumor drugs: synthesis,characterization, and evaluation of their in vitro cytotoxicity

Doxorubicin-loaded micelles were prepared from a copolymer comprising cholic acid (CA) and polyethyleneimine (PEI) for the delivery of antitumor drugs. The CA-PEI copolymer was synthesized via pairing mediated by N,N’-dicyclohexylcarbodiimide and N-hydroxysuccinimide using dichloromethane as a solvent. Fourier transform infrared and nuclear magnetic resonance analyses were performed to verify the formation of an amide linkage between CA and PEI and doxorubicin localization into the copolymer. Dynamic light scattering and transmission electron microscopy studies revealed that the copolymer could self-assemble into micelles with a spherical morphology and an average diameter of <200 nm. The CA-PEI copolymer was also characterized by X-ray diffraction and differential scanning calorimetry. Doxorubicin-loaded micelles were prepared by dialysis method. A drug release study showed reduced drug release with escalating drug content. In a cytotoxicity assay using human colorectal adenocarcinoma (DLD-1) cells, the doxorubicin-loaded CA-PEI micelles exhibited better antitumor activity than that shown by doxorubicin. This is the first study on CA-PEI micelles as doxorubicin carriers, and this study demonstrated that they are promising candidates as carriers for sustained targeted antitumor drug delivery system.     

A one-pass algorithm for shape-preserving quadratic spline interpolation

Schumaker (1983) and McAllister and Roulier (1981) have proposed algorithms for shape-preserving interpolation using quadratic splines. The former requires the user to provide and perhaps to adjust estimates of the slope at the data points. Here we show that, for a particular slope estimation technique, the two methods are identical, and that in this case the Schumaker algorithm automatically generates shape-preserving interpolants. Furthermore, in case of convex data the slopes are improved iteratively to produce more visually pleasing curves.