A low power reconfigurable multi-mode continuous time Delta Sigma modulator for seven different mobile standards with VCO-based quantizer

In this research a novel low power multi-mode continuous time Delta Sigma modulator was designed to be compatible with many mobile wireless standards. This modulator has a reconfigurable structure to adapt to various standards from 0.2 to 20 MHz. The designed modulator uses a VCO-based quantizer not only for lowering power consumption, but also for reducing the required chip area. The presented modulator can function with up to third order of noise shaping, or in a low power mode in which the loop filter is disabled and only the VCO-based quantizer is used. The proposed modulator was implemented and simulated in transistor level in 180 nm technology. This modulator can digitize at least seven standards (LTE (20 MHz)/WLAN/LTE (9 MHz)/WCDMA/UMTS/Bluetooth/GSM) with a favorable dynamic range (65–89 dB) and power consumption (9.1 mW–670 μW).     

Synthesis and characterization of biodegradable block copolymers of poly(propylene fumarate‐co‐sebacate)‐co‐poly(ethylene glycol) and poly(ethylene fumarate‐co‐sebacate)‐co‐poly(ethylene glycol)

The synthesis of two low molecular weight linear unsaturated oligoester precursors, poly(propylene fumarate‐co‐sebacate) (PPFS) and poly(ethylene fumarate‐co‐sebacate) (PEFS), are described. PPFS, PEFS, and poly(ethylene glycol) are then used to prepare poly(propylene fumarate‐co‐sebacate)‐co‐poly(ethylene glycol) (PPFS‐co‐PEG) and poly(ethylene fumarate‐co‐sebacate)‐co‐poly(ethylene glycol) (PEFS‐co‐PEG) block copolymers. The products thus obtained are investigated in terms of the molecular weight, composition, structure, thermal properties, and solubility behavior. A number of design parameters including the molecular weights of PPFS, PEFS, and PEG, the reaction time in the polymer synthesis, and the weight ratio of PEG to PPFS or to PEFS are varied to assess their effects on the product yield and properties. The hydrolytic degradation of PPFS‐co‐PEG and PEFS‐co‐PEG in an isotonic buffer (pH 7.4, 37°C) is investigated, and it is found that the fumarate ester bond cleaves faster than does the sebacate ester bond. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 295–300, 2004     

Evaluation of repeatability and reproducibility of continuous friction measuring equipment (CFME) using cross-correlation

Lack of sufficient friction between tyre and pavement is known to be one of the contributing factors in vehicle crashes. The application of new technologies can be used to determine the low friction areas or vulnerable accident sites at both the project and network levels. Continuous friction devices are one of the newest systems currently used in European countries that have recently been introduced to the United States. Continuous friction measuring devices are designed to measure the friction under conditions similar to those produced by an anti-lock braking system. Although continuous friction measuring equipment (CFME) provides valuable information about surface friction, processing of the relatively large amount of data produced is time-consuming. Traditional methods such as comparing the average friction provide a quick and simple data analysis method; however, they neglect other important characteristics such as friction spatial variation and low friction spots. This study proposes a methodology based on cross-correlation to compare CFME measurements. The data used in the study were collected during the annual rodeo that took place at the Virginia Smart Road. Two GripTester and one Dynatest 6875H Highway Friction Tester were used for data collection. Cross-correlation was used to synchronise the measurements. Repeatability and reproducibility of the measurements were evaluated based on the maximum cross-correlation value.     

Nigella sativa L. improves lipid profile and prevents atherosclerosis: Evidence from an experimental study on hypercholesterolemic rabbits

The effects of Nigella sativa (NS) on lipid profile, C-reactive protein, oxidized LDL, antioxidant capacity, Apo A and Apo B and fatty streak formation in hypercholesterolemic male rabbits were examined. Fifteen rabbits were distributed into three groups of five each [normal diet, hypercholesterolemic diet (1% cholesterol) and hypercholesterolemic diet (1% cholesterol) supplemented with 5% NS]. They received rabbit laboratory chow diet for a period of 8 weeks. At the start and end of the study, fasting blood was taken from all animals. NS significantly decreased fatty streak formation as well as total cholesterol (TC) and low-density lipoprotein (LDL) in hypercholesterolemic male rabbits. NS showed positive effects on other factors (triacylglycerol, high-density lipoprotein, C-reactive protein, oxidized LDL, antioxidant capacity, Apo A and Apo B), but these were insignificant. Based on favorable efficiency of NS on TC and LDL reduction and its anti-atherogenic cardioprotective properties, it is suggested using this plant with fat-rich diets simultaneously may reduce their adverse health effects.     

Oversampled multi-phase time-domain bit-error rate processing for transmitter testing

High speed serial interfaces (HSSI) are continually pushed toward operating at higher speed to meet the demand for higher bandwidth. As a result, the timing constraints for HSSI devices get tighter. Consequently, HSSI devices experience issues such as timing jitter and bit-errors. This paper investigates techniques to speed up HSSI bit-error rate and jitter testing. The proposed oversampling-based transmitter test scheme accelerates transmitter jitter and eye diagram testing by means of a multi-phase bit-error rate test circuit (BERT). The proposed scheme creates parallel BERT elements working in conjunction that are able to digitize the input signal jitter behavior in a multi-phase manner. The more phases we deploy the faster the test is completed. We accurately extract the transmitter jitter in time domain and finish the whole transmitter test within tens of milliseconds, exceeding the current norm of 100 ms.     

Contouring control of a 3-[P2(US)] parallel manipulator

A three-translational degree of freedom parallel mechanism is introduced in this research. Kinematic and dynamic modelling of the parallel mechanism is investigated and equations of motion are derived via Lagrange formulation. Reduced dynamic equations of the robot are represented as a matrix form for implementation in inverse dynamics control of the constrained system. Equivalent contouring errors are represented in moving tangent-normal coordinates system in joint space. Contouring control of the robot is applied to the system using inverse-dynamics-based feedback linearization technique and application of the control technique is represented through two proposed manoeuvres for robot motion. Trajectory planning of the end-effector path is performed by specification of some accuracy points and cubic spline interpolation through them. Response performance in contour following of the control system is improved by appropriate choice of control parameters and by decoupling of error dynamics via assigning suitable structures for control matrices. The results of practical implementation of the control technique show proper accuracy of the control system in following two desired trajectories and acceptable errors are created with respect to the desired contours.     

Numerical investigations on swirl intensity decay rate for turbulent swirling flow in a fixed pipe

Due to the importance of predicting the SIDR¹ associated with engineering problems such as combustion chambers, draft tube of the Francis and Kaplan turbines, heat exchanger tubes, separators and so forth, in this research the trend of SIDR and its affecting factors, through a turbulent swirl decay pipe flow have been investigated. The swirling flow is created by means of a rotating honeycomb which produces solid body rotation at the inlet of a fixed pipe. First of all, turbulent swirling decay flow has been numerically surveyed using different flow conditions at the pipe inlet. The numerical results have been validated and compared with the existing experimental data and mathematical relations, showing satisfactory coincide. The obtained results show that, the SIDR depends mainly on the Reynolds number of the passing flow. On this basis, correlations have been proposed in order to improve the predictions of swirl intensity decay rate at upstream regions as well as those with high swirl intensity. In addition, conducted analyses demonstrates (analyses have been made to demonstrate) that the previous developed correlations for predicting swirl intensity decay rate, agree with those provided in this study only for regions far enough from downstream having the low swirl intensity. This implies that the swirl intensity decay rate should be a function of the type of swirl generator at the pipe inlet.     

Dendrosomes as novel gene porters‐III

BACKGROUND: It was previously reported that dendrosomes, i.e. neutral, biodegradable, covalent or self‐assembled, hyperbranched, spheroidal nano‐particles with a size ranging from 15 to 100 nm, provide a convenient and efficient means of gene delivery into various kinds of cells such as human hepatoma and kidney cells as well as animal models. RESULTS: New studies via circular dichroism show that hydrophilic and amphipathic dendrosomes either do not affect the DNA structure or moderately transform it from B‐ to A‐conformation. Gene delivery into human liver, kidney, and endothelial cells as well as other animal cells like Bowes, U‐937, Raw, CCRF‐CEM, MOLT‐4, K562, Huh‐7 and VERO reveal that the genes are efficiently expressed and in comparison with other gene porters like Lipofectin or bacterial ghosts, do quite well. It is also shown that dendrosomes are able to deliver genes into cells like endothelials that are usually hard to transfect. Cell culture experiments as well as intraperitoneal/intradermal injections of dendrosomes into mice establish their nontoxicity (up to 2.5 mg kg^?1 of animal weight in the latter case). Studies on immunization of BALB/c mice using conventional adjuvants such as aluminium phosphate, C_pG motif and one of the dendrosomes, indicate that the latter leads to the mildest initial response development while exceeding them afterwards. CONCLUSION: CD studies reveal that, owing to the neutrality of dendrosomes, formation of Den/DNA complexes is accompanied by slight structural modifications of DNA cell culture, and animal studies reveal that dendrosomes are inert, non‐toxic and highly efficient gene porters that perform at extremely low doses. In comparison with bacterial ghosts and some common porters, they are efficient in delivery of genes into animals and a variety of cells including those that are usually hard to transfect. Copyright © 2008 Society of Chemical Industry     

Diesel engine performance and exhaust emission analysis using waste cooking biodiesel fuel with an artificial neural network

This study deals with artificial neural network (ANN) modeling of a diesel engine using waste cooking biodiesel fuel to predict the brake power, torque, specific fuel consumption and exhaust emissions of the engine. To acquire data for training and testing the proposed ANN, a two cylinders, four-stroke diesel engine was fuelled with waste vegetable cooking biodiesel and diesel fuel blends and operated at different engine speeds. The properties of biodiesel produced from waste vegetable oil was measured based on ASTM standards. The experimental results revealed that blends of waste vegetable oil methyl ester with diesel fuel provide better engine performance and improved emission characteristics. Using some of the experimental data for training, an ANN model was developed based on standard Back-Propagation algorithm for the engine. Multi layer perception network (MLP) was used for non-linear mapping between the input and output parameters. Different activation functions and several rules were used to assess the percentage error between the desired and the predicted values. It was observed that the ANN model can predict the engine performance and exhaust emissions quite well with correlation coefficient (R) 0.9487, 0.999, 0.929 and 0.999 for the engine torque, SFC, CO and HC emissions, respectively. The prediction MSE (Mean Square Error) error was between the desired outputs as measured values and the simulated values were obtained as 0.0004 by the model.