A new simple method for analysing of thermal noise in switched-capacitor filters

Thermal noise is one of the most important challenges in analogue integrated circuits design. This problem is more crucial in switched-capacitor (SC) filters due to the aliasing effect of wide-band thermal noise. In this article, a new simple method is proposed for estimating the power spectrum density of output thermal noise in SC filters, which have acceptable accuracy and short running time. In the proposed method, first using HSPICE simulator, accurate value of accumulated sampled noise on sampler capacitors in each clock state is achieved. Next, using difference equations of the SC filter, frequency response of the SC filter is shaped by time domain analysis. Based on the proposed method, a SC low-pass filter and a second-order SC band-pass filter are analysed. The results are validated by comparing to the previously measured data.     

Exfoliated Graphitic Carbon Nitride for the Fast Adsorption of Metal Ions from Acid Mine Drainage: A Case Study from the Sungun Copper Mine

Mine Water and the Environment - Graphitic carbon nitride (g-C3N4) was easily synthesized from melamine and subsequently sonicated to create exfoliated g-C3N4. Samples were characterized with...     

STABILITY PREDICTION OF TITANIUM MILLING WITH DATA DRIVEN RECONSTRUCTION OF PHASE-SPACE

Significant research effort has been carried out in the detection of chatter, which is one of the main barriers against titanium milling. State-of-the-art techniques are unable to satisfy requirements of industry in terms of in-process chatter detection. The present study reports the use of sensor-signal driven reconstructed phase space attractors combined with image correlation as a solution of chatter prediction during milling of titanium in industry. The method uses Poincaré sections of reconstructed phase space attractor as patterns to identify the onset of chatter in the apparently random behavior of vibrations in the milling process. Image correlation of Poincaré sections indicates the onset of chatter in the milling process.     

Provably correct control flow graphs from Java bytecode programs with exceptions

We present an algorithm for extracting control flow graphs from Java bytecode that captures normal as well as exceptional control flow. We prove its correctness, in the sense that the behaviour of the extracted control flow graph is a sound over-approximation of the behaviour of the original program. This makes control flow graphs suitable for performing various static analyses, such as model checking of temporal safety properties. Analysing exceptional control flow for Java bytecode is difficult because of the stack-based nature of the language. We therefore develop the extraction in two stages. In the first, we abstract away from the complications arising from exceptional flows, and relativize the extraction on an oracle that is able to look into the stack and predict the exceptions that can be raised at each instruction. This idealized algorithm provides a specification for concrete extraction algorithms, which have to provide a suitable implementation for the oracle. We prove correctness of the idealized algorithm by means of behavioural simulation. In the second stage, we develop a concrete extraction algorithm that consists of two phases. In the first phase, the program is transformed into a BIR program, a stack-less intermediate representation of Java bytecode, from which the control flow graph is extracted in the second phase. We use this intermediate format because it provides the information needed to implement the oracle, and since it gives rise to more compact graphs. We show that the behaviour of the control flow graph extracted via the intermediate representation is a sound over-approximation of the behaviour of the graph extracted by the direct, idealized algorithm, and thus of the original program. The concrete extraction algorithm is implemented as the ConFlEx tool. A number of test cases are performed to evaluate the efficiency of the algorithm.     

Assessing the effectiveness of disease awareness programs: Evidence from Google Trends data for the world awareness dates

Objectives

The process of disease awareness distribution on the web was studied. The contribution of WHO world awareness days to the total awareness process over the internet was investigated.

Investigation of inter‐relationship between tensile behavior and photocatalytic activity of an acrylic‐based composite upon UVA exposure

The aim of this work is to produce a photocatalytic pseudo‐paint for benzene removal from air and find the role of TiO₂ nanoparticles, TiO₂ pigment, and CaCO₃ extender on photocatalytic performance of this paint along with their role on stress–strain behavior after ultraviolet (UV) exposure. For this purpose, TiO₂ nanoparticles were dispersed into an indoor paint resin (i.e., copolymer acrylic–styrene). The impact of main components of the paint on photocatalytic oxidation (PCO) rate of benzene was studied. It was found that dispersion of nanoparticles had the most dramatic effect on photo activity of nanocomposite. TiO₂ pigment generally increased PCO rate and also made the paint more stable under tensile stress. CaCO₃ may increase and/or decrease PCO of benzene, whether there is pigment in the formulation or not. However, it does not generally contribute to making the formulation resistant to UV exposure. Nanoparticles bring PCO and mechanical strength into the paint, but fail to strengthen the composite against UV deterioration. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44447.     

Analysis and suppression of spurious modes of the ring shape anchored RF MEMS contour mode disk resonator

One of the most encumbering issues in RF MEMS resonators is spurious modes. The problem of spurious modes becomes more critical, when the ring type resonators are used. In the ring shape anchored contour mode disk resonator, for achieving a low serial resistance, the inner radius of the disk must be increased. This causes the spurious modes to become too close to the desired mode and degrade the operation of the resonator. In this work, spurious modes of before-mentioned device are introduced and their characteristics are evaluated by exact analytical approach. Based on those analytical approaches, we introduce two techniques for spurious mode suppression. The first technique is based on exciting the desired mode by proper electrode engineering and hence is an electrical approach. The second technique is reconfiguring of the anchor from a continuous ring to crossed ring segments and locating the segments on the phase discriminating lines to increase the insertion loss for spurious modes and decrease the losses for the fundamental mode. The final harmonic analysis verifies that the proposed techniques result a resonator with a pure frequency spectrum and spurious modes excluded over a very wide frequency range.

     

Precise analytical evaluation of the ring shape anchored contour mode disk resonator for constructing a low noise UHF Pierce oscillator

This paper presents an analytical evaluation of the previously demonstrated Ring Shape Anchored Contour Mode Disk (RSACMD) resonator and extracts its equivalent electrical circuit. In the next step, a series resonant Pierce oscillator is designed and parameterized based on the calculated MEMS characteristics. Due to the inherent 180° of phase shift in the RSACMD resonator equivalent circuit, a modified version of a Pierce sustaining circuit is introduced with two inverters (instead of one inverter in conventional Pierce oscillators) to compensate that extra phase shift and satisfy Barkhausen criteria. The designed circuit presents excellent phase noise performance because of a special design which results in small frequency pulling and enable the circuit oscillate close to natural frequency of the high Q resonator. The overall circuit consumes less than 257 μW from a 1.8 V power supply.