Semi-globally Exponential Tracking Observer/Controller for Robots with Joint Hysteresis and Without Velocity Measurement

In this work, we consider a multiple degree of freedom robotic plant with joint hysteresis and without velocity measurement. We show, by construction, how a semi-globally exponential hysteresis observer/controller that assumes velocity measurement, a number of which we point out from the literature, can be combined/modified with a velocity observer to yield a combined semi-globally exponential tracking observer/controller. The resulting observer/controller estimates both the hysteresis state and the joint velocity. We prove that the combined estimation error and tracking error converges to zero semi-globally exponentially. One deemed contribution as compared to previous work for this same type of plant is that the usual requirement of velocity measurement has been removed; another is the proved semi-globally exponential result.     

Photoresponsive measurements on InAs0·3Sb0·7 infrared detector

This paper presents a study of responsivity of InAs_0·3Sb_0·7 infrared detector. Thin films of InAs_0·3Sb_0·7 semiconducting compound were prepared by vacuum evaporation on glass and mica substrates held at 473° K under a pressure of 10⁻⁶ torr with deposition rate of 20 A°/sec. The isothermal annealing process was employed to improve the quality of the films. The responsivity variation with blackbody temperature (333° K to 673° K), detector temperature (80° K to 303° K) and frequency (10 Hz to 10 kHz) was measured. The experimental set-up and the results are presented and discussed.     

Structure-composition-property dependence in reactive magnetron sputtered ZnO thin films

Thin films of zinc oxide (ZnO) were prepared by dc reactive magnetron sputtering on glass substrates at various oxygen partial pressures in the range 1×10⁻⁴–6×10⁻³ mbar and substrate temperatures in the range 548–723 K. The variation of cathode potential of zinc target on the oxygen partial pressure was explained in terms of target poisoning effects. The stoichiometry of the films has improved with the increase in the oxygen partial pressure. The films were polycrystalline with wurtzite structure. The films formed at higher substrate temperatures were (0 0 2) oriented. The temperature dependence of Hall mobility of the films formed at various substrate temperatures indicated that the grain boundary scattering of charge carriers was predominant electrical conduction mechanism in these films. The optical band gap of the films increased with the increase of substrate temperature. The ZnO films formed under optimized oxygen partial pressure of 1×10⁻³ mbar and substrate temperature of 663 K exhibited low electrical resistivity of 6.9×10⁻² Ω cm, high visible optical transmittance of 83%, optical band gap of 3.28 eV and a figure of merit of 78 Ω⁻¹ cm⁻¹.     

Synthesis and Biological Evaluation of Benzo[b]furans as Inhibitors of Tubulin Polymerization and Inducers of Apoptosis

A series of benzo[b]furans was synthesized with modification at the 5‐position of the benzene ring by introducing C‐linked substituents (aryl, alkenyl, alkynyl, etc.). These compounds were evaluated for their antiproliferative activities, inhibition of tubulin polymerization, and cell‐cycle effects. Some compounds in this series displayed excellent activity in the nanomolar range against lung cancer (A549) and renal cell carcinoma (ACHN) cancer cell lines. (6‐Methoxy‐5‐((4‐methoxyphenyl)ethynyl)‐3‐methylbenzofuran‐2‐yl)(3,4,5‐trimethoxyphenyl)methanone ( 26 ) and (E)‐3‐(6‐methoxy‐3‐methyl‐2‐(1‐(3,4,5‐trimethoxyphenyl)vinyl)benzofuran‐5‐yl)prop‐2‐en‐1‐ol ( 36 ) showed significant activity in the A549 cell line, with IC₅₀ values of 0.08 and 0.06 μM , respectively. G₂/M cell‐cycle arrest and subsequent apoptosis was observed in the A549 cell line after treatment with these compounds. The most active compound in this series, 36 , also inhibited tubulin polymerization with a value similar to that of combretastatin A‐4 (1.95 and 1.86 μM , respectively). Furthermore, detailed biological studies such as Hoechst 33258 staining, DNA fragmentation and caspase‐3 assays, and western blot analyses with the pro‐apoptotic protein Bax and the anti‐apoptotic protein Bcl‐2 also suggested that these compounds induce cell death by apoptosis. Molecular docking studies indicated that compound 36 interacts and binds efficiently with the tubulin protein.     

Optimal Groundwater Management in Deltaic Regions using Simulated Annealing and Neural Networks

This study deals with the optimal management of groundwater in deltaic aquifer systems with some reference to east coastal hydro-geo-climatic conditions of India. A system of cooperative wells is proposed to supplement surface water sources to meet the demand during the non-monsoon season, without inducing excessive saltwater intrusion. The management models are solved as nonlinear, non-convex, combinatorial problems. The management models are solved by interfacing simulated annealing (SA) algorithm with an existing SHARP interface flow model to determine an optimal policy for location and pumpages of cooperative wells. Computational burden arising from SA algorithm is managed within practical timeframes by replacing the simulator with an artificial neural network (ANN).     

Dielectric properties of Al V2O5 Al thin film sandwich structures

Vanadium pentoxide thin films were prepared by the electron beam evaporation technique onto Corning 7059 glass substrates kept at a temperature of T_s=423 K. The dielectric properties of Al V₂O₅ Al thin film sandwich structures were studied in the frequency range 0.1–100 kHz and in the temperature range 125–450 K. Both the dielectric constant and the dielectric loss factor were found to depend on frequency and temperature. The activation energy obtained for the dielectric relaxation process was about 0.36 eV.     

Three novel single-stage full swing 3-input XOR

In this paper, three novel designs for single-stage, 3-input XOR logic cells are proposed. The design uses either Transmission Gate (TG) or Pass Transistor (PT) on similar topologies. The proposed circuits are area and power efficient because minimum-sized transistors are used in ratioless realisations. At the output, the designs give strong logic-levels. The topologies have minimised delay because the critical path consists of only three minimum-sized transistors. The delay estimation is presented. The circuits are simple and layouts are easy to build. Further, rail-to-rail voltage-swing at the output ensures good driving capability even at low voltages and at high frequencies ranging up to 10 GHz with minimum transistor count. The proposed designs and other existing candidate designs are simulated in a pragmatic condition on Cadence 90 nm CMOS technology at various supply voltages ranging from +0.8 V to +1.2 V. The simulation results illustrate that the proposed designs have comparable delay time to most candidate designs while it outperform all of them on total power consumption and PDP. As expected, the TG-based design reports best performance while the PT-based design follow as closed second with better component economy and control input overload. An application of the proposed XORs in ripple carry adders confirms the functionality of the cells in circuit implementation.     

A high gain low noise amplifier for implantable cardio technologies

Microsystem Technologies - Increase in large number of neurological and cardiovascular illness that cannot be treated by medicine alone have brought about a critical development in the quantity of...