Single production of fourth-family quarks at the LHC

We study the single production of fourth-family quarks through the process pp→Q′jX at the Large Hadron Collider (LHC). We have calculated the decay widths and branching ratios of the fourth-family quarks (b′ and t′) in the mass range 300–800 GeV. The cross sections for the signal and background processes have been calculated in a Monte Carlo framework. It is shown that the LHC can discover single t′ and b′ quarks if the CKM matrix elements |V _t′q |,|V _qb′|≳0.01.     

Théorie des processus stochastiques généraux applications aux surmartingales

Sans résuméCe nous est un très agréable devoir d'adresser ici nos plus vifs remerciements à Monsieur J. Paris qui a bien voulu, avec une bienveillance toute particulière, veiller au meilleur déroulement de ce travail, partie de notre thèse de doctorat défendue à l'Université Catholique de Louvain.Nous sommes également très reconnaissants à Monsieur P.A. Meyer, qui nous a signalé la seconde partie du théorème 12.     

Stability of Ritz procedure for nonlinear two-point boundary value problem

In this paper we establish the stability of Ritz procedure in sense of Michlin and Tucker for a class of nonlinear two-point boundary value problems which has been considered by Varga, Schultz and Ciarlet in [1].     

Analysis of fluorescence quenching of pyronin B and pyronin Y by molecular oxygen in aqueous solution

The fluorescence quenching of pyronin B and pyronin Y molecules by molecular oxygen in aqueous solution was studied by using steady-state and time-resolved fluorescence and UV-Vis absorption spectroscopy techniques. In order to understand the quenching mechanism, fluorescence decays, absorption and fluorescence spectra of the probes were recorded as a function of the oxygen concentration and temperature. The quenching was found to be appreciable and shows positive deviation in the Stern-Volmer representation obtained from the fluorescence intensity ratio. Fluorescence quenching constants (k_q) were calculated from the τ_o/τ vs. [Q] plots having linear correlation and compared with calculated diffusion-controlled rate constants (k_diff) values. Experimental results were in good agreement with the simultaneous dynamic and static quenching model.     

Synthesis,Characterization, and Antibacterial Activity of Novel Pyridones

Novel ethyl 2-oxo-4,6-diaryl-1,2,3,4-tetrahydropyridine-3-carboxylate and 4,6-diaryl-3,4-dihydropyridine-2(1H)-one derivatives have been synthesized from the cyclization of adducts of diethylmalonate to chalcones with ammonium acetate. The structures were established on the basis of extensive spectroscopic methods and further confirmed by X-ray crystallographic analysis. Antibacterial activity of obtained pyridones was investigated against four human pathogen microorganisms and the compounds showed poor activity.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Microstructural properties of sintered Al–Cu–Mg–Sn alloys

A non-commercial Al4Cu0.5Mg alloy has been used for investigating the effects of the elemental Sn additions. Uniaxial die compaction response of the alloys in terms of green density was examined, and the results showed that Sn addition has no effect when compacting conducted under high pressures. In total, 93–95% green density was achieved with an applied pressure of 400 MPa. Thermal events occurring during the sintering of the emerging alloys were studied by using differential scanning calorimetry (DSC). First thermal event on the DSC analysis of the Al4Cu0.5Mg1Sn alloy is the melting of elemental Sn, whereas for Al4Cu0.5Mg alloy, it is the formation of Al–Mg liquid nearly at 450 °C. Also it is clearly seen on the DSC analysis that Sn addition led to an increase in the formation enthalpy of Al–Mg liquid phase. High Sn content and high sintering temperature (620 °C), therefore high liquid-phase content, caused decrease on the mechanical properties due to thick intergranular phases and grain coarsening. Highest transverse rupture strength and hardness values were obtained from Al4Cu0.5Mg0.1Sn alloy sintered at 600 °C and measured as 390 MPa and 73 HB, respectively.     

Simulation and hybrid fuzzy-PID control for positioning of a hydraulic system

Accuracy and precision of position control of hydraulic systems are key parameters for engineering applications in order to set more economical and quality systems. In this context, this paper presents modeling and position control of a hydraulic actuation system consisting of an asymmetric hydraulic cylinder driven by a four way, three position proportional valve. In this system model, the bulk modulus is considered as a variable. In addition, the Hybrid Fuzzy-PID Controller with Coupled Rules (HFPIDCR) is proposed for position control of the hydraulic system and its performance is tested by simulation studies. The novel aspect of this controller is to combine fuzzy logic and PID controllers in terms of a switching condition. Simulation results of the HFPIDCR based controller are compared with the results of classical PID, Fuzzy Logic Controller (FLC), and Hybrid Fuzzy-PID controller (HFPID). As a result, it is demonstrated that Hybrid Fuzzy PID Controller with Coupled Rules is more effective than other controllers.     

Locally Optimal Risk-Sensitive Controllers for Strict-Feedback Nonlinear Systems1,2

For a class of risk-sensitive nonlinear stochastic control problems with dynamics in strict-feedback form, we obtain through a constructive derivation state-feedback controllers which (i) are locally optimal, (ii) are globally inverse optimal, and (iii) lead to closed-loop system trajectories that are bounded in probability. The first feature implies that a linearized version of these controllers solve a linear exponential-quadratic Gaussian (LEQG) problem, and the second feature says that there exists an appropriate cost function according to which these controllers are optimal.