The influence of mineral admixtures on the short and long-term performance of concrete

This paper presents a laboratory study on the performance of concrete by adding mineral admixtures, silica fumes (SF) or/and fly ash (FA). Performance of the concrete mixes was determined with short and long-term tests, which include compressive strength, porosity, capillary absorption, wet–dry cycle and accelerated carbonation. The test results, in general, showed that mineral admixtures improved the performance of concretes. SF contributed to both short and long-term properties of concrete, whereas FA shows its beneficial effect in a relatively longer time. As far as the compressive strength is concerned, adding of both SF and FA slightly increased compressive strength, but contributed more to the improvement of transport properties of concretes.     

Studies on Extraction of Protein Isolates from Turkish sunflowerseed and Cottonseed Extraction Cakes and on their Functional Properties

In this study trials have been made to produce protein isolates from sunflowerseed and cottonseed cakes which are two of the three major edible oil sources of Turkey, besides olive. Our experiments yielded the best solvent systems for extraction, the optimum H values for protein precipitation for each seed cake. Using these optimum parameters, we could succeed in extracting about 55% of the proteins contained in the cakes, and preparing isolates which contained more than 90% protein. The functional properties of the obtained isolates, such as protein dispersibility index, water and oil adsorption capacities and emulsion activity were determined. the amino acid compositions of the oilseed cakes as well as of the respective protein isolates were also determined and compared to the FAO protein reference model.     

Modeling and Estimation of the Dynamics of Planar Algebraic Curves via Riccati Equations

Motivated by problems in vision and robotics, in this paper we are interested in describing the dynamics of planar algebraic curves in rigid and affine motion. A new method is presented for modeling the dynamics of such curves in terms of Riccati equations. It is shown that rigid or affine motion of an algebraic curve can be described using the dynamics of line factors obtained from a unique decomposition of the curve, and each individual line dynamics can be described by a Riccati equation. An estimation algorithm is proposed to estimate rigid or affine motion using line parameters. Importance of data normalization is also investigated in the context of motion estimation. Experiments with simulated data and real images demonstrate that the proposed method can provide satisfactory motion estimation results from perturbed data.     

A 60 μW 60 nV/√Hz Readout Front-End for Portable Biopotential Acquisition Systems

There is a growing demand for low-power, small-size and ambulatory biopotential acquisition systems. A crucial and important block of this acquisition system is the analog readout front-end. We have implemented a low-power and low-noise readout front-end with configurable characteristics for Electroencephalogram (EEG), Electrocardiogram (ECG), and Electromyogram (EMG) signals. Key to its performance is the new AC-coupled chopped instrumentation amplifier (ACCIA), which uses a low power current feedback instrumentation amplifier (IA). Thus, while chopping filters the 1/f noise of CMOS transistors and increases the CMRR, AC coupling is capable of rejecting differential electrode offset (DEO) up to plusmn50 mV from conventional Ag/AgCl electrodes. The ACCIA achieves 120 dB CMRR and 57 nV/radicHz input-referred voltage noise density, while consuming 11.1 muA from a 3 V supply. The chopping spike filter (CSF) stage filters the chopping spikes generated by the input chopper of ACCIA and the digitally controllable variable gain stage is used to set the gain and the bandwidth of the front-end. The front-end is implemented in a 0.5 mum CMOS process. Total current consumption is 20 muA from 3V     

用模糊逻辑控制(ABS)系统改善制动性能和方向稳定性

ABS系统设计了一简单有效的模糊逻辑控制,可改善汽车制动时的制动性能,以及在均匀和不均匀(μ-分离表面)的摩擦表面上的转向制动的机动性。该系统由前后两工作控制器组成。第一控制器工作于纵向滑动,第二控制器负责车辆侧向滑动控制。在非线性轮胎特性的四轮非线性车辆模型上实行模糊逻辑控制。同时与没有模糊逻辑控制ABS系统的车辆模型比较,评估控制器性能。     

Integrated low-power 24-channel EEG front-end

The first integrated CMOS multichannel electroencephalogram (EEG) readout front-end, capable of extracting EEG signals from conventional AgCl electrodes without the use of any trimmed components, is presented. Each channel of the ASIC achieves better than 90 dB common-mode rejection ratio (CMRR) at 50 Hz with 50 mV DC offset between EEG electrodes. This is consistent with the presented formula describing the CMRR behaviour of the preamplifier under DC electrode offset. The front-end includes 24 channels and consumes 10.5 mW from a 3 V supply.     

Technologies for highly miniaturized autonomous sensor networks

Recent results of the autonomous sensor research program HUMAN++ will be summarized in this paper. The research program aims to achieve highly miniaturized and (nearly) autonomous sensor systems that assist our health and comfort. Although the application examples are dedicated to human monitoring/assistance, the necessary technology development for this program is generic and can serve many wireless sensor applications. This multi-disciplinary program combines research on wireless ultra-low-power communications, research on 2D/3D integration and packaging platforms, energy scavenging techniques, as well as low-power and ultra-low-power sensor circuit design. An example sensor system is the wearable wireless EEG system.     

Fluid flow in microtubes with axial conduction including rarefaction and viscous dissipation

Graetz problem inside the microtube is revisited considering rarefaction effect, viscous dissipation term and axial conduction in the fluid for uniform wall temperature boundary condition in the slip flow regime. The flow is assumed to be hydrodynamically fully developed, thermally developing, and the velocity profile is solved analytically. The temperature field is determined by the numerical solution of the energy equation. The rarefaction effect is imposed to the problem via velocity-slip and temperature jump boundary conditions. The local and fully developed Nu numbers are obtained in terms of dimensionless parameters; Pe, Kn, Br, κ. Fully developed Nu numbers and the thermal entrance length are found to increase by the presence of the finite axial conduction.     

A design methodology for power‐efficient reconfigurable SC ΔΣ modulators

This paper presents a methodology to design reconfigurable switched‐capacitor delta‐sigma modulators (ΔΣMs) capable of keeping their corresponding power efficiency figures constant and optimal for a set of resolutions and signal bandwidths. This method is especially suitable for low‐bandwidth, medium‐to‐high‐resolution specifications, which are common in biomedical application range. The presented methodology is based on an analytic model of all different contributions to the power dissipation of the ΔΣM. In particular, a novel way to predict the static power dissipated by integrators based on class A and class AB operational transconductance amplifier is presented. The power‐optimal solution is found in terms of filter order, quantizer resolution, oversampling ratio, and capacitor dimensions for a targeted resolution and bandwidth. As the size of the sampling capacitors is crucial to determine power consumption, three approaches to achieve reconfigurability are compared: sizing the sampling capacitors to achieve the highest resolution and keep them constant, change only the first sampling capacitor according to the targeted resolution, or program all sampling capacitors to the required resolution. The second approach results in the best trade‐off between power efficiency and simplicity. A reconfigurable ΔΣM for biomedical applications is designed at transistor level in a 0.18‐µm complementary metal–oxide–semiconductor process following the methodology discussed. A comparison between the power estimated by the proposed analytic model and the transistor implementation shows a maximum difference of 17%, validating thus the proposed approach. Copyright © 2014 John Wiley & Sons, Ltd.