High Frequency

The current-mode instrumentation amplifier based on second-generation current conveyors (CCII) offers many benefits over conventional instrumentation amplifier architectures. It does not need any matched components to achieve high CMRR and its bandwidth is not gain-bandwidth product limited. Therefore, the wideband CMOS current conveyor has been used in this structure. HSPICE simulations have shown that its performance is quite satisfactory for wideband current-mode signal processing. Furthermore, different CMRR enhancement techniques of current-mode instrumentation amplifiers are discussed. The new simulated instrumentation amplifier provides approximately 40 dB of improvement on the high-frequency CMRR up to the 3-dB corner frequency and even higher. In addition, composite conveyor techniques improving the instrumentation amplifier performance are presented

The impact of ultrasound (US) on membrane filtration and cleaning were studied and compared at various operating parameters of nominal pore sizes of 10 and 100 kDa membrane, trans-membrane pressure (TMP) of 100 and 140 kPa, and US frequencies of 20 kHz and 40 kHz. An average of 15%–20% increase of permeability was observed when US (20 kHz) was applied to assist membrane filtration on 10 kDa membrane and 100 kPa trans-membrane pressure (TMP). However, an insignificant improvement was observed in the case of larger pore size membrane at higher TMP (140 kPa). US also augmented the membrane cleaning process effectively. Lower frequency 20 kHz US exhibited a higher flux recovery (>90%) than the high frequency 40 kHz (59%) using the 10 kDa pore size membrane with US-assisted membrane cleaning. Important factors influencing optimization of US effectiveness lie heavily on its configuration and operation. The experimental results as supported with SEM images demonstrate that US-assisted filtration and cleaning are most effective when membrane pore size, US frequency, and TMP are lower.

We present an audio-visual Virtual Reality display system for simulated sound fields. This system combines the simulation of acoustics inside closed rooms, different approaches for visualizing the sound propagation as well as the auralization of the resulting signals. The room acoustic simulation is performed by use of a particle tracing algorithm, the Phonon Tracing, applied at middle and high frequency range, combined with a wave-based approach (FEM solver) utilized for low frequencies. For a realistic representation of the simulation results we use a stereoscopic back projection system for rendering as well as a professional sound system for audio reproduction. For auralization purposes we developed a soundfield synthesis approach for accurate control of the loudspeaker system.

We use an agent-based approach to model trading behaviour in high-frequency markets. This study focuses on the Foreign Exchange (FX) market. The initial part of this study is to observe the micro-behaviour of traders to define the stylized facts of their trading activities. This is performed using a high- frequency dataset of anonymised individual traders' historical transactions on an account

An equivalent diagram with localized constants has been created to represent the two winding transformer. The equivalent diagram with localized constants is practically independent of the transformer construction. Only the numeric constants change from one component to another. This circuit can be introduced into converter simulation software, and leads to very realistic forecasts even when working at high frequency. The

In the nondestructive inspection of aerospace materials and structures, water-coupled ultrasonic inspection is often not desirable due to contamination and property alteration concerns. Examples include composite and foam structures in space applications and honeycomb sandwiches that cannot tolerate water ingression. For practical and operational reasons, water-coupled ultrasound is also not preferred for on-aircraft inspection in maintenance hangars. Non-contact, air-coupled ultrasonic transducers are therefore an attractive alternative for such applications. This paper describes our experience of using piezoceramic air-coupled transducers for flaw detection and repair evaluation of composite parts. The paper first discusses the basic principles of air-coupled ultrasonic measurement and laboratory tests of various materials and structures, followed by a description of a portable, manual, air-coupled ultrasonic scan system that allowed the use of air-coupled ultrasound in the field ...

Current research in capsule endoscopy aims at endowing the capsules with some means of actively propelling themselves inside the gastrointestinal (GO tract, as opposed Advantages of these active capsules are the sipificant potential in the duration of the associated diagnostic procedures. as well as the oossihilitv to direct the line-of-sieht of the oh-hoard cameras towards interesting features of the GI tissue. One such means of active propulsion is by vibratory actuation, employing eccentric-mass micromotors, which is shown to reduce the friction of the capsule with the GI tract. The effect of vibrations on the quality of the acquired images is explored in the present study, which demonstrates that such vibrations do not affect adversely the diagnostic effectiveness of the endoscopic capsules. The parameters of vibratory actuation are evaluated as to the loss bf high-frequency information in the acquired images, due to the induced motion blur, and appropriate design guidelines for...

Climate variability and change are expected to influence the seasonal cycle in North Pacific sub-arctic marine ecosystems. The hypothesis that timing of nesting and productivity of piscivorous seabirds [kittiwakes (Rissa tridactyla and Rissa brevirostris) and murres (Uria aalge and Uria lomvia)] at the Pribilof Islands are related to variation in ocean climate as indexed by changes in sea-ice concentrations (SICs)

Abstract— This paper presents an adaptive control scheme for suppressing jitter in laser beams. The variable-order adaptive controller is based on an adaptive lattice filter that implicitly identifies the disturbance statistics from real-time sensor data. The multi-channel adaptive ...

In 1997 the Italian Space Agency (ASI) started the Science Small Missions (PMS, Piccole Missioni Scientifiche) program, fulfilling an explicit recommendation included in the Italian National Space Plan. On a competitive basis, at the end of 1998, ASI selected two missions for the first cycle of the program: AGILE, a light gamma-ray telescope, and DAVID, carrying two experiments for signal

Burkitt’s lymphoma (BL) in Turkish children is commonly associated with Epstein–Barr virus (EBV) infection. The C-terminus of the latent membrane protein 1 (LMP-1) of EBV is essential for transformation and the 30-bp deletion detected in this region has been implicated to be associated with a more aggressive malignant phenotype. To understand the molecular mechanisms underlying EBV pathogenesis in BL of

This paper comprises a comparison between the vegetation response in ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) multispectral optical imagery and possibly equivalent bedrock/regolith/soil response in airborne gamma-ray spectrometry grids, employing a tropical rainforest area in the Brazilian Amazon as a control. The applied technique comprised band ratios using a fixed near infrared band (numerator) divided by individual visible and shortwave infrared bands (denominator). These band ratios were subsequently submitted to principal component analysis, and the high frequency information is smoothed by low pass filtering. The colour compositions selected for interpretation were sharpened by the first principal component of the original ASTER bands through an IHS transform in order to add albedo/texture information lost through band rationing back to the imagery. The products show a plausible coherence with airborne gamma-ray data and field observations, provi...