H<Subscript>∞</Subscript> control of multiple model subject to actuator saturation: application to quarter-car suspension system

This paper deals with the H_∞ control of nonlinear systems in multiple model representation subject to actuator saturation. An application to Quarter-Car suspension system under actuator saturation is then given using the multiple model approach. The concept of so-called parallel distributed compensation (PDC) is employed for designing control system. The idea of this controller consists in designing a linear feedback control for each local linear model. To address the input saturation problem in this paper, both constrained and saturated controls input cases are proposed. In the two cases, H_∞ stabilization conditions in the sense of Lyapunov method are derived. Moreover, a controller design with larger attraction domain is formulated and solved as a linear matrix inequality (LMI) optimization problem. Our simulation results show that both the saturated and constrained controls can stabilize the resulting closed-loop suspension system and eliminate the effect of external disturbances. Indeed, the main roles of car suspension systems, which consist on improving ride comfort of passengers and the road holding capacity of the vehicle, are achieved.     

Graphene oxide a promising formaldehyde scavenger of phenolic resin-bonded plywood: From elaboration to evaluation

A long-standing manufactured and most frequently used resin is phenol-formaldehyde resin, which has currently reached new horizons by incorporating nano reinforcements, even at lower loadings. Nanostructured materials, particularly graphene, have gained considerable interest in recent years because of their fascinating characteristics. Herein, this study explores for the first time the potential of prepared graphene oxide (GnO) as an effective formaldehyde scavenger in the development of plywood panels containing PF resins. The addition of 1% of GnO to the system resulted in a significant improvements in the mechanical properties by more than 45% in the shear strength (SS), 35% in modulus of elasticity, and 25% in modulus of rupture when compared with the reference panel. While the moisture resistance of panels were found to remarkably enhanced showing an increase in SS by 25% and 37% After 24 h in cold water (20°C) and 12 h of immersion in boiling water, respectively. The results also demonstrated that GnO exhibited exceptional formaldehyde capture efficiency, surpassing 60% reduction compared with the control. This innovative research not only unveils the novel potential of GnO in improving the performance of PF resins but also ushers in a new way of developing eco-friendly wood-based materials.     

Synthesis and Biological Evaluation of 2-Aminobenzamide Derivatives as Antimicrobial Agents: Opening/Closing Pharmacophore Site

A series of new 2-aminobenzamide derivatives (1–10) has been synthesized in good to excellent yields by adopting both conventional and/or a time-efficient microwave assisted methodologies starting from isatoic anhydride (ISA) and characterized on the basis of their physical, spectral and microanalytical data. Selected compounds of this series were then tested against various bacterial (Bacillus subtilis (RCMB 000107) and Staphylococcus aureus (RCMB 000106). Pseudomonas aeruginosa (RCMB 000102) and Escherichia coli (RCMB 000103) and fungal strains (Saccharomyces cerevisiae (RCMB 006002), Aspergillus fumigatus (RCMB 002003) and Candida albicans (RCMB 005002) to explore their potential as antimicrobial agents. Compound 5 was found to be the most active compound among those tested, which showed excellent antifungal activity against Aspergillus fumigatus (RCMB 002003) more potent than standard Clotrimazole, and moderate to good antibacterial and antifungal activity against most of the other strains of bacteria and fungi. Furthermore, potential pharmacophore sites were identified and their activity was related with the structures in the solution.     

New 3-((2′:2″,5″:2-terthiophene)-3″-yl) acrylic acid as active layer for organic field-effect transistor

Most functionalized thiophenes are difficult to electropolymerize due to nucleophilicity that will attack the radical cation inhibiting polymerization. However, we have successfully electrodeposited a newly synthesized functionalized terthiophene monomer 3-((2′:2″,5″:2-terthiophene)-3″-yl) acrylic acid (TAA) as an active layer of a organic field-effect transistor (OFET). The polymer was then oxidized in order to increase its conductivity. Various oxidizing potentials were experimented and their effect on the OFET's charge mobility was examined. A mobility of 0.25 cm² (V s)⁻¹ is achieved with an oxidizing potential of 0.9 V after vacuum drying.     

Vibrating interventional device detection using real-time 3-D color Doppler

Ultrasound image guidance of interventional devices during minimally invasive surgery provides the clinician with improved soft tissue contrast while reducing ionizing radiation exposure. One problem with ultrasound image guidance is poor visualization of the device tip during the clinical procedure. We have described previously guidance of several interventional devices using a real-time 3-D (RT3-D) ultrasound system with 3-D color Doppler combined with the ColorMark technology. We then developed an analytical model for a vibrating needle to maximize the tip vibrations and improve the reliability and sensitivity of our technique. In this paper, we use the analytical model and improved radiofrequency (RF) and color Doppler filters to detect two different vibrating devices in water tank experiments as well as in an in vivo canine experiment. We performed water tank experiments with four different 3- D transducers: a 5 MHz transesophageal (TEE) probe, a 5 MHz transthoracic (TTE) probe, a 5 MHz intracardiac catheter (ICE) transducer, and a 2.5 MHz commercial TTE probe. Each transducer was used to scan an aortic graft suspended in the water tank. An atrial septal puncture needle and an endomyocardial biopsy forceps, each vibrating at 1.3 kHz, were inserted into the vascular graft and were tracked using 3-D color Doppler. Improved RF and wall filters increased the detected color Doppler sensitivity by 14 dB. In three simultaneous planes from the in vivo 3-D scan, we identified both the septal puncture needle and the biopsy forceps within the right atrium using the 2.5 MHz probe. A new display filter was used to suppress the unwanted flash artifact associated with physiological motion.     

Lowering plasma homocysteine with vitamins B6, B12, and folic acid. Effect on lipids concentration in patients with secondary hyperlipoproteinemia type IV, with and without Lovastatina treatment

The concentration of plasma homocysteine was diminished by the oral use of vitamins B6 (300 mg/day), B12 (250 microg/day) and folic acid (10 mg/day), and the effect was studied in the lipids of patient with hiperlipoproteinemia secondary type IV, during 120 days, in 30 patients, 45 to 70 years old, with myocardial heart attack. They were divided in group A (n=15) without treatment with Lovastatin and group B (n=15) with Lovastatin. Basal homocysteine concentration was 17.4 +/- 1.0 micromol/L and 16.7 +/- 1.0 micromol/L for the groups A and B respectively, diminishing 24% at the end of the experimental time, in both groups. Total cholesterol decreased below 220 mg/dl, while the triglycerides diminished 25.4 mg/dl and 27.0 mg/dl in groups A and B respectively, by each micromol/L of homocysteine catabolissed. Low density lipoproteins (LDL) and very low density (VLDL) diminished significantly (p < 0.005), while the high-density (HDL) increased 1.0 mg/dl in group A and 1.15 mg/dl in group B, for each micromol/L of homocysteine metabolized, lowering the coronary risk factor in 28.5% group A and 35.9% group B. We concluded that these vitamins decreased plasma homocysteine concentration, promoting the lowering of lipids and lipoprotein concentratation in this type of patients; while Lovastatin doesn't reduce homocysteine, but it had a synergic effect with the vitamins, dicreasing the lipid concentration, in group B.     

Modification of Langmuir model for simulating initial pH and temperature effects on sorption process

ABSTRACT

The present study modifies the sorption isotherm for simulating the influences of initial pH and temperature variations on the cadmium sorption from contaminated water using waste foundry sand based on Langmuir, Freundlich, and Temkin models. Results proved that the Langmuir expression is able to adopt these effects by relating sorption capacity and affinity constants with pH and temperature of aqueous solution through exponential relationships (determination coefficient = 0.9375). The present model is assumed that the sorption process occurs through acidic functional groups and this is consistent with FTIR outputs. Interaction of cadmium/WFS is found to be exothermic by thermodynamic analysis.     

Authentication of Commercial Extra Virgin Olive Oils

The goal of the current contribution is to determine the geographical origins of olive oil samples obtained from eight different countries during the harvest seasons of 2013 and 2014. First, the contents of olive oil samples were quantified by integrating the peaks of ¹H‐NMR spectra and using linear mathematical equations. The results were analyzed by analysis of variance (ANOVA), a statistical method examining whether there is a significant difference between the groups mean. The origins of the majority of the olive oil samples were discriminated by ANOVA and the minor constituents of the olive oils. Tocopherol and cycloartenol were the most discriminative minor constituents of the olive oil samples.     

Differential modulation for asynchronous two‐way relay systems over frequency‐selective fading channels

We propose two schemes for asynchronous multi‐relay two‐way relay (MR‐TWR) systems in which neither the users nor the relays know the channel state information. In an MR‐TWR system, two users exchange their messages with the help of N_R relays. Most of the existing works on MR‐TWR systems based on differential modulation assume perfect symbol‐level synchronization between all communicating nodes. However, this assumption is not valid in many practical systems, which makes the design of differentially modulated schemes more challenging. Therefore, we design differential modulation schemes that can tolerate timing misalignment under frequency‐selective fading. We investigate the performance of the proposed schemes in terms of either probability of bit error or pairwise error probability. Through numerical examples, we show that the proposed schemes outperform existing competing solutions in the literature, especially for high signal‐to‐noise ratio values. Copyright © 2016 John Wiley & Sons, Ltd.