On manimax theory in two Hilbert spaces

In this paper, we investigated the minimax of the bifunction J:H1(Ω)xV2→RmxRn, such that J(v1,v2)=((12a(v1,v1)−L(v1)),v2) where a(.,.) is a finite symmetric bilinear bicontinuous, coercive form on H1(Ω) and L belongs to the dual of H1(Ω)

A Practical Fast Acting Control Scheme For Fuzzy Logic-Based Voltage Stabilization Control

This paper presents a simplified control model for stabilizing a load voltage using a switched reactor in parallel with a fixed capacitor of static VAR compensator. Two IGBT’s are used to control the reactance of the switched reactor. A uniform pulse width modulation is used for controlling the two switches. The compensator has a simple control circuit and structure. A complete modeling and numerical simulation for the proposed systems is presented. A high speed Digital Signal Processor is used for implementing proportional-integral (PI) and fuzzy load voltage controllers. Experimental results indicate the superiority of fuzzy logic control over the conventional proportional-integral control method. Simulation results are reported and proved to be in good agreement with the relevant experimental results

Performance improvement of existing three phase synchronous reluctance machine : stator upgrading to 5-phase with combined star-pentagon winding

This paper investigates the performance of 3-phase synchronous reluctance machines (SynRMs) when upgrading their stator to 5-phase, keeping the same rotor. The design of the 5-phase stator has been optimized to select the optimal dimensions of the slots and teeth. Moreover, a combined star-pentagon winding is employed to further improve the machine performance. Different winding configurations have been studied and compared using 2D Ansys Maxwell transient simulations. It is observed that at optimal current angle and rated current, the average torque is increased by 17.41% when changing the 3-phase stator with the proposed 5-phase one. In addition, the efficiency of the 5-phase SynRM is increased by about 0.8% compared to 3-phase SynRM. At 3 times the rated speed, the torque and efficiency are significantly increased by around 33% and 3.5% respectively. Moreover, the 5-phase SynRM shows a superior performance in the faulty case with one phase opened. It works at 98.84% of the rated torque of the healthy 3-phase machine, whereas the 3-phase machine works at only 43.35% with huge torque ripple (228%). Finally, an experimental validation using the reference 3-phase machine has been done

Time-Resolved Reflection High-Energy Electron Diffraction Study of the Ge(111)-c(2×8)-(1×1) Phase Transition

The dynamics of the Ge(111)-c(2×8)-(1×1) phase transition is investigated by 100-ps time-resolved reflection high-energy electron diffraction. A laser pulse heats the surface while a synchronized electron pulse is used to obtain the surface diffraction pattern. Slow heating shows that the adatoms in Ge(111)-c(2×8) start to disorder at ∼510 K and are converted to a disordered adatom arrangement at 573 K. For heating with 100-ps laser pulses, the Ge(111)-c(2×8) reconstructed adatom arrangement starts to disorder at 584±16K, well above the onset temperature of ∼510 K for the disordering of Ge(111)-c(2×8) observed for slow heating. © 1999 The American Physical Society

A Modified Open Loop Control of a Matrix Converter Connected to Wind Energy System

Wind energy conversion system (WECS) is bit by bit gaining interest as a suitable source of renewable energy. In this paper a direct AC-AC matrix converter is utilized to interface an isolated static load fed from WECS. A self-excited induction generator is utilized as it has many advantages in terms of ease of maintenance, self-protection against short circuits. This paper proposes a modified open loop control of matrix converter with indirect space vector modulation. The modified open loop provides constant output voltage and constant frequency even if the wind speed changed. Matrix converter (MC) is used rather than AC-DC-AC converter as it eliminates the bulky capacitors. Finally, simulation results for different operating points are displayed which are consistent with the expected results. </p

Effect of vitamin B17 on experimentally induced colon cancer in adult male albino rat

Background: Colon cancer is considered to be the third most common cancer worldwide. At diagnosis of colon cancer, 3.7–11% developed bone metastasis. Diet based strategies are important for prevention and treatment of colon cancer. This study investigated the effect of vitamin B17 on a DMH induced rat model of colon cancer. Materials and methods: Eighty young adult male albino rats were divided into five groups: group I (control group), group II (vitamin B17), group III (colon cancer), group IV (protected) and group V (treated). Distal colon sections were prepared for light and scanning electron microscopic examination. Lumbar vertebrae specimens were prepared for light microscopic study. Morphometric and statistical analysis were done. Results: In comparison with the control, both colon cancer and treated groups showed invasion of the colonic tissue by pleomorphic branching colonic glands of variable shapes and sizes lined with dysplastic elongated hyperchromatic nuclei with frequent mitotic figures or stratified multi-layered crowded nuclei with an extremely significant (p &lt; 0.0001) reduction of goblet cell number when compared to the control together with major pathological bone changes were observed in colon cancer and the treated groups. Conclusions: While the protected group showed impressive improvement of all previously mentioned diameters

Investigating the Response of Human Neutrophils to Hydrophilic and Hydrophobic Micro-Rough Titanium Surfaces.

Various treatments have been used to change both the topography and chemistry of titanium surfaces, aiming to enhance tissue response and reduce healing times of endosseous implants. Most studies to date focused on bone healing around dental implants occurring later during the healing cascade. However, the impact of the initial inflammatory response in the surgical wound site on the success and healing time of dental implants is crucial for implant integration and success, yet it is still poorly understood. The purpose of this study was to investigate the effect of titanium surface hydrophilicity on the response of human neutrophils by monitoring oxygen radical production, which was measured as chemiluminescence activity. Materials and Methods: Neutrophils were isolated from human donors' blood buffy coats using the double sucrose gradient method. Neutrophils were exposed to both hydrophilic and hydrophobic titanium surfaces with identical topographies in the presence and absence of human serum. This resulted in six experimental groups including two different implant surfaces, with and without exposure to human serum, and two control groups including an active control with cells alone and a passive control with no cells. Two samples from each group were fixed and analyzed by SEM. Comparisons between surface treatments for differences in chemiluminescence values were performed using analysis of variance ANOVA. Results and Conclusion: In the absence of exposure to serum, there was no significant difference noted between the reaction of neutrophils to hydrophilic and hydrophobic surfaces. However, there was a significant reduction in the mean and active chemiluminescence activity of neutrophils to serum-coated hydrophilic titanium surfaces than to serum-coated hydrophobic titanium surfaces. This suggests that surface hydrophilicity promotes enhanced adsorption of serum proteins, which leads to decreased provocation of initial immune cells and reduction of local oxygen radical production during wound healing. This can help explain the faster osseointegration demonstrated by hydrophilic titanium implants

Vitamin C attenuates the toxic effect of nutmeg on primary visual occipital cortex in rats

Background: Nutmeg is neurotoxic in rats and possibly neurotoxic also in hu- mans. The aim of this study is to investigate the effect of nutmeg on the primary visual occipital cortex of adult male rat and to evaluate the possible protective role of vitamin C.  Materials and methods: Fifty Sprague-Dawley adults male rats were randomly divided into three main groups; control, nutmeg-treated (500 and 1000 mg/kg/ /day) and protected groups (nutmeg + vitamin C [500 mg/kg/day]). All rats were treated orally by gavage for 5 days per week for 6 weeks. At the end of the experiment, primary visual occipital cerebral cortex was subjected to histological, immunohistochemical and genetic analyses.  Results: Our results revealed toxic effects of nutmeg on the primary visual occipital cerebral cortex in adult male albino rat. This was indicated by histopathological alterations, including pyknotic nuclei surrounded with vacuolations by light micro- scopic studies and degenerations of organelles by electron microscopic studies. In addition, we detected an increase in immunoreactivity for GFAP and caspase-3 by immunohistochemical assessments. Apoptotic bands appeared in genetic studies. Co-administration of vitamin C ameliorated nutmeg-induced toxic alterations on the primary visual occipital cerebral cortex.  Conclusions: Nutmeg administration caused histopathological and genetic changes in the primary visual occipital cerebral cortex in adult male albino rats. These changes were improved by co-administration of vitamin C.