New voltage-mode universal filter and sinusoidal oscillator using only single DBTA

In this article, a new voltage-mode second-order universal frequency filter and sinusoidal oscillator using only single differential-input buffered and transconductance amplifier (DBTA) is presented. The proposed voltage-mode filter structure using single DBTA and four passive elements can provide all standard filter functions, i.e. low-, band-, high-pass, band-stop, and all-pass without changing the circuit topology and enables independent control of the quality factor Q using single passive element. The circuit requires the minimal number of active and passive elements with no conditions for component matching. By slight modification of the proposed filter structure, the new DBTA-based sinusoidal oscillator is easily obtained. The oscillation condition and the oscillation frequency are independently adjustable by different virtually grounded passive elements. The proposed sinusoidal oscillator employs only grounded capacitors. The passive and active sensitivities of all the proposed circuit configurations are low. PSPICE simulations using a BJT realisation of DBTA and experimental results based on commercially available amplifiers OPA860 and MAX436 are included, which prove the workability of the proposed circuits.     

An electronically tunable current-mode quadrature oscillator using PCAs

This article presents a new realisation of active RC sinusoidal oscillator with electronically tunable condition and frequency of oscillation (FO). As compared to the class of three resistors, two capacitors (3R-2C)-based canonic oscillators, the circuit proposed here uses only two resistors and two capacitors as the passive components and still provides non-interactive tuning laws for the condition of oscillation and the FO. The proposed circuit employs new bipolar programmable current amplifier as the active building block and is capable of simultaneously providing two explicit quadrature current outputs. SPICE simulation results have been included to verify the workability of the circuit as an oscillator and the tuning range of the FO.     

New resistorless and electronically tunable realization of dual-output VM all-pass filter using VDIBA

In this paper, a new active element called voltage differencing inverting buffered amplifier (VDIBA) is presented. Using single VDIBA and a capacitor, a new resistorless voltage-mode (VM) first-order all-pass filter (APF) is proposed, which provides both inverting and non-inverting outputs at the same configuration simultaneously. The pole frequency of the filter can be electronically controlled by means of bias current of the internal transconductance. No component-matching conditions are required and it has low sensitivity. In addition, the parasitic and loading effects are also investigated. By connecting two newly introduced APFs in open loop a novel second-order APF is proposed. As another application, the proposed VM APF is connected in cascade to a lossy integrator in a closed loop to design a four-phase quadrature oscillator. The theoretical results are verified by SPICE simulations using TSMC 0.18 μm level-7 CMOS process parameters with ±0.9 V supply voltages. Moreover, the behavior of the proposed VM APF was also experimentally measured using commercially available integrated circuit OPA860 by Texas Instruments.     

Some insights from recent applications of HRA methods in PSA effort and plant operation feedback in Czech Republic

The methods of human reliability analysis (HRA) form an integral part of probabilistic safety assessment. These methods are currently still under development and there is significant lack of data needed for applications. As a consequence, no unique formal approach for solution of many aspects related to plant staff human performance does exist.In this contribution, some examples of fruitful work are given, which reflect the needs and possibilities specific for HRA field. In the first two examples, methodology, course and results of analysis of concrete matters related to pre-accident errors and shutdown control room crew performance are described. The last example is oriented to one potential human performance related data source-observation of control room crew full-scope simulator exercise. Some conclusions of general validity are presented in the final part of the contribution.     

APPLICATION OF CHROMATIC MONITORING AS A PLASMA DIAGNOSTIC TECHNIQUE

This paper describes the application of chromatic monitoring of both laboratory and industrial plasmas. The light emitted from the nitrogen plasma generated in the different plasma sources was measured with an imaging spectrograph. The emission spectra were reduced to data points representing the chromatic coordinates of these spectra. The data compression makes this method attractive for monitoring plasma parameter changes. The aim of this work was to test the possibility of application of chromatic monitoring for plasma processing.     

Study of structure and properties of ZnO–Bi<Subscript>2</Subscript>O<Subscript>3</Subscript>–P<Subscript>2</Subscript>O<Subscript>5</Subscript> glasses

Glasses of the ternary system ZnO–Bi₂O₃–P₂O₅ were prepared and studied in two compositional series 50ZnO–xBi₂O₃–(50 − x)P₂O₅ and (50 − y)ZnO–yBi₂O₃–50P₂O₅. Two distinct glass-forming regions were found in the 50ZnO–xBi₂O₃–(50 − x)P₂O₅ glass series with x = 0–10 and 20–35 mol.% Bi₂O₃. All prepared Bi₂O₃-containing glasses reveal a high chemical durability. Small additions of Bi₂O₃ (∼5 mol.%) improve thermal stability of glasses. All glasses crystallize on heating within the temperature range of 505–583 °C. Structural studies by Raman and ³¹P MAS NMR spectroscopies showed the rapid depolymerisation of phosphate chains within the first region with x = 0–15 and the presence of isolated Q⁰ phosphate units within the second region with x = 20–35. Raman studies showed that bismuth is incorporated in the glass structure in BiO₆ units and their vibrational bands were observed within the spectral region of 350–700 cm⁻¹. The evolution of properties and the spectroscopic data are both in accordance with a network former effect of Bi₂O₃.     

Distributed algorithms for barrier coverage using relocatable sensors

We study the barrier coverage problem using relocatable sensor nodes. We assume each sensor can sense an intruder or event inside its sensing range. Sensors are initially located at arbitrary positions on the barrier and can move along the barrier. The goal is to find final positions for sensors so that the entire barrier is covered. In recent years, the problem has been studied extensively in the centralized setting. In this paper, we study a barrier coverage problem in the distributed and discrete setting. We assume that we have n identical sensors located at grid positions on the barrier, and that each sensor repeatedly executes a Look-Compute-Move cycle: based on what it sees in its vicinity, it makes a decision on where to move, and moves to its next position. We make two strong but realistic restrictions on the capabilities of sensors: they have a constant visibility range and can move only a constant distance in every cycle. In this model, we give the first two distributed algorithms that achieve barrier coverage for a line segment barrier when there are enough nodes in the network to cover the entire barrier. Our algorithms are synchronous, and local in the sense that sensors make their decisions independently based only on what they see within their constant visibility range. One of our algorithms is oblivious whereas the other uses two bits of memory at each sensor to store the type of move made in the previous step. We show that our oblivious algorithm terminates within \(\varTheta (n^2)\) steps with the barrier fully covered, while the constant-memory algorithm is shown to take \(\varTheta (n)\) steps to terminate in the worst case. Since any algorithm in which a sensor can only move a constant distance in one step requires \(\varOmega (n)\) steps on some inputs, our second algorithm is asymptotically optimal.     

Mechanochemical synthesis of ternary chalcogenide chalcostibite CuSbS2 and its characterization

Journal of Materials Science: Materials in Electronics - In this work, the very rapid one-step mechanochemical synthesis of nanocrystalline ternary chalcogenide chalcostibite CuSbS2 prepared from...