A versatile access to new halogenated 7-azidocoumarins for photoaffinity labeling: Synthesis and photophysical properties

A versatile methodology for the synthesis of 6/8-halogenated 7-aminocoumarins from the corresponding 7-hydroxy analogs using Pd-catalyzed amination reaction as the key step is presented. Further readily conversion into 7-azidocoumarins was performed and the resulting aryl azides proved higher stability and reactivity than the corresponding non-halogenated parent compound. These new compounds may thus constitute attractive scaffolds for designing novel photoaffinity reagents for various challenging bio-labeling applications.     

Wind turbulence used as searching signal for MPPT in variable-speed wind energy conversion systems

The control problem associated to a class of horizontal-axis fixed-pitch variable-speed low-power wind energy conversion systems, working in the partial load region, consisting in the energy conversion maximization, is approached here under the assumption that the wind turbine model and its parameters are poorly known. Using a new approach derived from the optimum seeking methods category, generically called Maximum Power Point Tracking (MPPT), the proposed control solution aims at driving the average position of the operating point near to optimality. Instead of inducing sinusoidal search signals, the wind turbulence is here used as search disturbance. The high-speed shaft's average rotational speed is slowly adjusted using the Fast Fourier Transform processing of some available measures from the system as an estimate of the operating point's position/distance to optimality. Numerical simulations are used for preliminary checking the control law based on this estimation.     

A study of rolling bearing fatigue life with mineral oil lubrication

Tests on mineral oil lubricated deep groove ball bearings show that there is an optimum lubricant viscosity to ensure maximum rolling contact fatigue life. The results are explained by lubricant film thickness measurements and the application of E.H.L. theory. The optimum lubricant viscosity increases with increase of load and decreases with reduction of speed.     

Multilevel optimization algorithms in computer aided production control in process industry

The use of optimization techniques in production control is discussed. Two optimization problems in relation to typical process industry complexes are formulated. A modified version of Tamura's algorithm is reviewed. The promising performance of the computerised algorithms is illustrated by numerical results. DISPATCHER, a practical operative decision support system, is described.     

New super-orthogonal space-time trellis codes using differential M-PSK for noncoherent mobile communication systems with two transmit antennas

In this paper, we develop super-orthogonal space-time trellis codes (SOSTTCs) using differential binary phase-shift keying, quadriphase-shift keying and eight-phase shift keying for noncoherent communication systems with two transmit antennas without channel state information at the receiver. Based on a differential encoding scheme proposed by Tarokh and Jafarkhani, we propose a new decoding algorithm with reduced decoding complexity. To evaluate the performance of the SOSTTCs by way of computer simulations, a geometric two-ring channel model is employed throughout. The simulation results show that the new decoding algorithm has the same decoding performance compared with the traditional decoding strategy, while it reduces significantly the overall computing complexity. As expected the system performance depends greatly on the antenna spacing and on the angular spread of the incoming waves. For fair comparison, we also design SOSTTCs for coherent detection of the same complexity as those demonstrated for the noncoherent case. As in the case of classical single antenna transmission systems, the coherent scheme outperforms the differential one by approximately 3 dB for SOSTTCs as well.     

Bifurcations in the mechanics of hypoelastic composite materials

This paper analyses the modification of a hypoelastic material behavior at the small variations of the material parameters, using elements of the bifurcation theory. The considered material is obtained by the combination of two granular hypoelastic materials, which have the memory of the initial stress state, and their stress work depends on stress history. Its constitutive equation is deduced by means of the constitutive equations of the component materials. In consequence, mechanical properties of those two materials are interpenetrated, generating, for the new material, domains of stability, as well as surfaces in stress space, surfaces on which the strain–stress system is not invertible. It results that it is necessary to choose correctly the component materials, their share and the process of forming the new material, so that the imposed solicitation by the operation conditions should be accessible to a composite material. When we are modelling, the choice of the component materials means the choice of their constitutive equations—the share of the component materials will fix the stability domain of the composite material—the forming process chosen correctly will determine that the initial stress state (from which the loading path will start) should be in the stability domain of the material.     

Subquadratic Algorithms for 3SUM

We obtain subquadratic algorithms for 3SUM on integers and rationals in several models. On a standard word RAM with w-bit words, we obtain a running time of . In the circuit RAM with one nonstandard AC ⁰ operation, we obtain . In external memory, we achieve O(n ²/(MB)), even under the standard assumption of data indivisibility. Cache-obliviously, we obtain a running time of . In all cases, our speedup is almost quadratic in the “parallelism” the model can afford, which may be the best possible. Our algorithms are Las Vegas randomized; time bounds hold in expectation, and in most cases, with high probability.