Analytic phase margin design

Doyle et al. (1992) presented an algorithm for analytic phase margin control design. Without special care, however, the compensator computed with this algorithm may not be a real rational function, The problem is evident when the plant has real unstable poles. In this case the algorithm requires a mapping of real points into complex values, and it is not clear that the resulting compensator has real coefficients. The purpose of this paper is to show how a complex mapping required in this algorithm can always be selected so that the compensator does have real coefficients     

Reliability-based optimization of laterally loaded piles

A general approach to the reliability-based analyses and the optimum designs of laterally loaded piles (LLOP) is presented. This approach takes into consideration all behavior and side constraints specified by standard specifications for piles. Additionally, the casual effect of corrosion of piles with time is considered in formulation with limiting state functions. The solution to reliability-based problems is obtained by a computer program (RELLOP). A general reliability based methodology is developed and implemented in the developed computer program (RELLOP) for both element and system limit states. Numerical examples demonstrating the feasibility of considering multiple limit states and system reliability requirements in the design of laterally loaded piles are presented. Effects on the reliability-based design solution of allowable reliability levels, and time of exposure to corrosion are also illustrated.     

Unexpected Interacting Effects of Physical (Radiation) and Chemical (Bisphenol A) Treatments on Male Reproductive Functions in Mice

For decades, numerous chemical pollutants have been described to interfere with endogenous hormone metabolism/signaling altering reproductive functions. Among these endocrine disrupting substances, Bisphenol A (BPA), a widely used compound, is known to negatively impact germ and somatic cells in the testis. Physical agents, such as ionizing radiation, were also described to perturb spermatogenesis. Despite the fact that we are constantly exposed to numerous environmental chemical and physical compounds, very few studies explore the impact of combined exposure to chemical and physical pollutants on reproductive health. The aim of this study was to describe the impact of fetal co-exposure to BPA and IR on testicular function in mice. We exposed pregnant mice to 10 µM BPA (corresponding to 0.5 mg/kg/day) in drinking water from 10.5 dpc until birth, and we irradiated mice with 0.2 Gy (γ-ray, RAD) at 12.5 days post-conception. Co-exposure to BPA and γ-ray induces DNA damage in fetal germ cells in an additive manner, leading to a long-lasting decrease in germ cell abundance. We also observed significant alteration of adult steroidogenesis by RAD exposure independently of the BPA exposure. This is illustrated by the downregulation of steroidogenic genes and the decrease of the number of adult Leydig cells. As a consequence, courtship behavior is modified, and male ultrasonic vocalizations associated with courtship decreased. In conclusion, this study provides evidence for the importance of broadening the concept of endocrine disruptors to include physical agents, leading to a reevaluation of risk management and regulatory decisions.     

Biochemical studies on proteins from cheese whey and blood plasma by-products

Efforts have been done to recover proteins from waste liquors rich in protein in a soluble form. Cheese whey and animal bloods are byproducts from the manufacture of cheese and meat. It contains a variety of proteins which can be reclaimed. The efficiency of protein precipitation from the sweet-cheese whey by the use of hydroxyethyl cellulose (HEC) was similar to that precipitated by the use of carboxymethyl cellulose (CMC). Both are greater than that precipitated by trichloro acetic acid. The same results of the efficiency of precipitation were attained when the plasma protein was precipitated. It was found that cheesewhey protein-HEC-complex and plasms protein-HEC-complex contain a large amount of essential amino acids. Electrophoretic separation of whey protein complex showed that β-Lactoglobulin forms the major fraction while in case of plasma protein complex albumin forms the major fraction. The fractionation patterns of different complexes with HEC, CMC or TCA gave the same components and about the same ratio. It appears from these results that HEC-protein complexes are preferable than CMC-protein complexes or proteins precipitated by TCA. Chemical analysis of whey protein complexes revealed that lactose content of whey protein-HEC-complex was higher than that of CMC-complex or protein precipitated by TCA. Elemental analysis of protein complexes showed that the level of sodium, phosphorus, and potassium was increased while that of copper or zinc decreased. Cellulose derivative protein complexes showed no significant effects on the liver or kindney function of albino rat and these results indicated that no toxic effect was observed from the uses of these protein complexes in feeding.     

Discontinuous Galerkin Finite-Element Method for Simulation of Flood in Crossroads

A numerical solution of the two-dimensional Saint Venant equations is presented for the study of the propagation of the floods through the crossroads of the city. The numerical scheme is a Runge-Kutta discontinuous Galerkin method (RKDG) with a slope limiter. The work studies the robustness and the stability of the method. The study is organized around three aspects: the prediction of the water depths, the location of the right and oblique hydraulic jumps in the crossing, and especially the distribution of the flow discharges in the downstream branches. The objective of this paper was to use the RKDG method in order to simulate supercritical flow in crossroads and to compare these simulations with experimental results and to show the advantage of this RKDG method compared to a second-order finite-volume method. A good agreement between the proposed method and the experimental data was found. The method is then able to simulate the flow patterns observed experimentally and to predict accurately the water depths, the location of the hydraulic jumps, and the discharge distribution in the downstream branches.     

Inactivation of pathogenic Klebsiella pneumoniae by CuO/TiO2 nanofibers: A multifunctional nanomaterial via one-step electrospinning

The fabrication and characterization of one-dimensional CuO/TiO₂ nanofibers with high photocatalytic and antibacterial activities are presented. The CuO/TiO₂ nanofibers were prepared by electrospinning of colloid composed of titanium isopropoxide, poly(vinylpyrroliodine) (PVP) and copper nanoparticles and calcination at 700 °C in air for 1 h. The antibacterial activity was tested using Klebsiella pneumoniae as model organism by calculation of the minimum inhibitory concentration (MIC). The obtained CuO/TiO₂ nanofibers showed prominent photocatalytic activity under visible light to degrade reactive black5 and reactive orange16 dyes in aqueous solutions and effectively catalyze K. pneumoniae inactivation. The decomposition process of the cell wall and cell membrane was directly observed by TEM analysis after the exposure of the K. pneumoniae to the nanofibers. Interestingly, the introduced photocatalyst can be reused with the same photocatalytic activity. Overall, the combination of CuO and TiO₂ can be synergistic and resulted in CuO/TiO₂ composite nanofibers having superior photocatalytic and antimicrobial potential to impede K. pneumoniae growth which causes bacterium to die ultimately.     

Power efficient scheduling over fading channel for cross‐layer optimization

We consider the minimization of long‐term average power consumption for packet transmission between a mobile station and the base station over Nakagami‐m fading channel. Power consumption is minimized by intelligent transmission scheduling design, with the average queuing delay and joint packet loss across MAC and physical layers being confined below certain levels. The problem is formulated as an infinite horizon constrained Markov decision problem and solved by linear programming (LP) method. The primary intention of this paper is to provide a visible paradigm on using LP method to optimize the performance of mobile wireless communication systems. We elaborate the detailed mathematical solution with consistent simulation experiments and emphasize the effectiveness of adaptive transmission scheduling for cross‐layer QoS provisioning. Copyright © 2010 John Wiley & Sons, Ltd.     

XRD, Magnetic and M?ssbauer Spectral Studies of?Ag x Ni1?x Fe2O4 Ferrite Nanoparticles

Nanophase Ag _x Ni_1?x Fe₂O₄ (x=0,0.2) ferrites were prepared by glycothermal method. The NiFe₂O₄ (x=0) nanosized sample was also produced by high-energy ball milling for comparison of properties. Structural investigations of the samples were carried out by X-ray diffraction. The experiment reveals that pure Ag-Ni ferrite materials with grain sizes of about 8 nm can be obtained after annealing at relatively low temperature of about 500?°C. The nanosized compounds produced by glycothermal reaction indicate superparamagnetic behavior. A higher value of coercive field (910 Oe) is observed in x=0 milled sample with similar particle size. The zero field cooled (ZFC) and field cooled (FC) magnetization measurements reveals spin glass like behavior of the nanosized compounds.