19 research outputs found

    Numerical simulation of fluid-structure interaction between fishing wobbler and water

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    This paper deals with modeling, discretization, and numerical analysis of the two-way fluid-structure interaction between a fishing wobbler and a water stream. The structural domain is an assembly of several bodies that have multiple mutual structure-to-structure interactions. These interactions are mostly nonlinear contacts that significantly influence the time step used in simulations. As a result of these nonlinearities, the numerical solving of such a model requires significant computer resources and a long computational time. The paper also presents the creation and numerical simplifications of the model. However, the model remains very realistic. It is concluded that solving the structural domain in a model that retains the interaction between solid bodies is more computationally sensitive and more demanding than solving the fluid domain

    Thermal stability of film forming amines-based corrosion inhibitors in high temperature power plant water solutions

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    Film forming amines (FFA) are corrosion inhibitors added to power plant water. The major concern associated with their application is the thermal stability in the high temperature power plant water medium, along with the risk of decomposition into low molecular weight organic acids that can cause corrosive damages in the water/steam cycle. However, there is still a lack of sufficient data on the thermal stability of FFA corrosion inhibitors. This paper presents a comprehensive critical review and state-of-the-art assessment of the results obtained from studying the thermolysis of FFA corrosion inhibitors in power plant water/steam cycle conditions, highlighting the relevance for practical application and research needs. Temperature, exposure time, initial concentration, and alkalizing agents were identified as key factors influencing the thermal stability of FFA in high temperature power plant water. Organic acids are found in concentrations harmless to metal tubes. Advanced scientific background information and additional research are required on this topic.Laboratory Water Managemen

    A 500uW 5MBps ULP super-regenerative RF front-end

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    This paper presents an ultra low power superregenerative RF front-end for wireless body area network (WBAN) applications. The RF front-end operates in the 2.36-2.4 GHz medical BAN and 2.4-2.485 GHz ISM bands, and consumes 500 µW. It supports OOK modulation at high data rates ranging from 1-5 Mbps. It achieves a sensitivity of -67 dBm at a BER of 10-3. The combination of digital and analog quench generation and RF front-end optimization provides ultra-low power consumption at high data rates. The RF front end is implemented in a 90 nm CMOS technology and is packaged in a QFN56 package

    A reconfigurable low-noise amplifier using a tunable active inductor for multistandard receivers

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    A reconfigurable low-noise amplifier (LNA) based on a high-value active inductor (AI) is presented in this paper. Instead of using a passive on-chip inductor, a high-value on-chip inductor with a wide tuning range is used in this circuit and results in a decrease in the physical silicon area when compared to a passive inductor-based implementation. The LNA is a common source cascade amplifier with RC feedback. A tunable active inductor is used as the amplifier output load, and for input and output impedance matching, a source follower with an RC network is used to provide a 50 Ω impedance. The amplifier circuit has been designed in 0.18 µm CMOS process and simulated using the Cadence Spectra circuit simulator. The simulation results show a reconfigurable frequency from 0.8 to 2.5 GHz, and tuning of the frequency band is achieved by using a CMOS voltage controlled variable resistor. For a selected 1.5 GHz frequency band, simulation results show S 21 (Gain) of 22 dB, S 11 of −18 dB, S 22 of −16 dB, NF of 3.02 dB, and a minimum NF (NFmin) of 1.7 dB. Power dissipation is 19.6 mW using a 1.8 V dc power supply. The total LNA physical silicon area is (200×150) µm2

    A 500μW 5Mbps ULP super-regenerative RF front-end

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    This paper presents an ultra low power super-regenerative RF front-end for wireless body area network (WBAN) applications. The RF front-end operates in the 2.36-2.4 GHz medical BAN and 2.4-2.485 GHz ISM bands, and consumes 500 μW. It supports OOK modulation at high data rates ranging from 1-5 Mbps. It achieves a sensitivity of -67 dBm at a BER of 10-3. The combination of digital and analog quench generation and RF front-end optimization provides ultra-low power consumption at high data rates. The RF front end is implemented in a 90 nm CMOS technology and is packaged in a QFN56 package. ©2010 IEEE

    A Precise and High Speed Charge-Pump PLL Model Based on SystemC/SystemC-AMS

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    The Phase Locked Loop (PLL) has become an important part of electrical systems. When designing a PLL, an efficient and reliable simulation platform for system evaluation is needed. However, the closed loop simulation of a PLL is time consuming. To address this problem, in this paper, a new PLL model containing both digital and analog parts based on SystemC/SystemC-AMS (BETA version) is presented. Many imperfections such as Voltage Control Oscillator (VCO) noise or reference jitter are included in this model. By comparing with the Matlab model, the SystemC/SystemC-AMS model can dramatically reduce simulation time. Also, by comparing with Analog Devices ADI SimPLL simulation results, Cadence simulation results and real measurement results, the accuracy of the SystemC/SystemC-AMS model is demonstrated. The paper shows the feasibility of a unified design environment for mixed-signal modelling based on SystemC/SystemC-AMS in order to reduce the cost and design time of electrical systems

    Overexpression of PTK6 (breast tumor kinase) protein - a prognostic factor for long-term breast cancer survival - is not due to gene amplification.

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    In a previous retrospective study, we demonstrated the prognostic value of protein tyrosine kinase 6 (PTK6) protein expression in breast carcinomas. Here, we analyzed PTK6 gene amplification using fluorescence in situ hybridization technique in a cohort of 426 invasive breast carcinomas and compared it with PTK6 expression level as well as with the clinical outcome of patients. Forty-five percent of tumors show increased PTK6 gene copy numbers when compared to normal tissue. Most of these, however, were related to chromosome 20 polysomy (30%), while gene amplification accounted for only 15%. Only "low level" amplification of the PTK6 gene, with up to eight signals per nucleus, was found. The PTK6 cytogenetic status (normal, gene amplification, polysomy 20) was not associated with histopathological parameters or with the protein expression of HER receptors. No statistical association was identified between PTK6 gene status and expression level. Further, the PTK6 gene status does not influence the disease-free survival of patients at a parts per thousand yen240 months. Based on these results, we state that the PTK6 overexpression is not essentially attributed to gene amplification, and the PTK6 protein expression-but not gene status-is of prognostic value in breast carcinomas. PTK6 protein overexpression may result from polysomy 20 in a minority of the tumors. In a marked proportion of tumors, however, the overexpression is likely to be caused by posttranscriptional regulation mechanisms

    Performance evaluation of an ultra-low power receiver for body area networks (BAN)

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    The main bottleneck to achieve energy autonomy in body area networks (BAN) is the design of an ultra low power yet reliable wireless system. In this paper, we first demonstrate the feasibility of an ultra low power receiver by presenting our implemented receiver chip that could operate on a total power of 479.5 uW, which is more than one order of magnitude lower than commercially available low power transceivers working at 2.4 GHz. We then show the reliability of this chip, which can achieve a receiver sensitivity of -72 dBm for a data rate of 1 Mbps. We further demonstrate that this receiver sensitivity is sufficient to guarantee reliability by evaluating this chip in different to-body communication in BAN environments. By using typical BAN channels, simulation results show that our system can provide a reliable link in both the standing and walking situations. With the measured data, we show that a transmit power of -15 dBm is sufficient for our receiver to achieve reliable communication link in different BAN environments. This transmit power requirement is 15 dB lower than the widely known low power Zigbee system. It could thus significantly facilitate the ultra low power transmitter design, and minimize the human exposure to radio frequency electromagnetic fields. The design and evaluation of our receiver presented in this paper therefore provides a way to move towards the energy autonomy of BAN, and opens access to many new applications in BAN
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