The role of channel height and actuation method on particle manipulation in surface acoustic wave (SAW)-driven microfluidic devices

Surface acoustic wave (SAW) micromanipulation offers modularity, easy integration into microfluidic devices and a high degree of flexibility. A major challenge for acoustic manipulation, however, is the existence of a lower limit on the minimum particle size that can be manipulated. As particle size reduces, the drag force resulting from acoustic streaming dominates over acoustic radiation forces; reducing this threshold is key to manipulating smaller specimens. To address this, we investigate a novel excitation configuration based on diffractive-acoustic SAW (DASAW) actuation and demonstrate a reduction in the critical minimum particle size which can be manipulated. DASAW exploits the inherent diffractive effects arising from a limited transducer area in a microchannel, requiring only a travelling SAW (TSAW) to generate time-averaged pressure gradients. We show that these acoustic fields focus particles at the channel walls, and further compare this excitation mode with more typical standing SAW (SSAW) actuation. Compared to SSAW, DASAW reduces acoustic streaming effects whilst generating a comparable pressure field. The result of these factors is a critical particle size with DASAW (1 $$\upmu$$ μ m) that is significantly smaller than that for SSAW actuation (1.85 $$\upmu$$ μ m), for polystyrene particles and a given $$\lambda _{\text {SAW}}$$ λ SAW = 200 $$\upmu$$ μ m. We further find that streaming magnitude can be tuned in a DASAW system by changing the channel height, noting optimum channel heights for particle collection as a function of the fluid wavelength at which streaming velocities are minimised in both DASAW and SSAW devices.

Assessment of artificial intelligence models for calculating optimum properties of lined channels

Lined channels with trapezoidal, rectangular and triangular sections are the most common manmade canals in practice. Since the construction cost plays a key role in water conveyance projects, it has been considered as the prominent factor in optimum channel designs. In this study, artificial neural networks (ANN) and genetic programming (GP) are used to determine optimum channel geometries for trapezoidal-family cross sections. For this purpose, the problem statement is treated as an optimization problem whose objective function and constraint are earthwork and lining costs and Manning's equation, respectively. The comparison remarkably demonstrates that the applied artificial intelligence (AI) models achieved much closer results to the numerical benchmark solutions than the available explicit equations for optimum design of lined channels with trapezoidal, rectangular and triangular sections. Also, investigating the average of absolute relative errors obtained for determination of dimensionless geometries of trapezoidal-family channels using AI models shows that this criterion will not be more than 0.0013 for the worst case, which indicates the high accuracy of AI models in optimum design of trapezoidal channels.

Timing Offset Correction and Channel Tap Estimation of OFDM Systems Over Frequency Selective Fading Channels

In OFDM systems we need to perfectly time synchronize the receiver to the transmitter to maximize its BER performance. In the absence of timing synchronization the channel estimation can never be optimum. Both timing synchronization and optimum channel estimation are the essential requirements to maximize the performance. We present an algorithm that uses the cyclic prefix to determine the timing offset of the system. The same algorithm can be used to determine the number of channel taps and their variances also. Determination of number of channel taps helps us in minimizing the length of the cyclic prefix to be added and also in the channel estimation, to minimize the variance of the estimation error. The knowledge of the variances of the channel taps helps us in further reducing the estimation error. We present in this paper the timing offset corrected MMSE channel estimation and show by simulations the effectiveness of the method presented.

Enhancing Throughput of Optimum Channel in of Dm Based Full Duplex Communication

The efficient use of radio facilities in cellular networks is essential and being widely studied. This letter sees a cellular relay system where various user couples perform trans-directional interaction via various relays relying on Orthogonal Frequency-Division Multiplexing (OFDM) communication.. Joint implementation of route and transmit allocation, along with subcarrier coupling, subcarrier distribution as well as relay choice, for complete output redistribution is identified as a combination estimation issue.. Using a graph conceptual strategy, we can efficiently fix the problem in exponential time by converting it into a Optimum Adjusted Bipartite Tracking (MWBM) issue. Simulation experiments are conducted to assess the complete throughput of the network versus transmitting energy per node and the number of relay nodes. Carrier frequency offset causes a number of impairments including attenuation and rotation of each of the subcarriers and intercarrier interference (ICI) between carrier frequency offset causes a number of impairments including attenuation and rotation of each of the subcarriers and intercarrier interference (ICI) between subcarriers. In the mobile radio environment, the relative movement between transmitter and receiver causes doppler frequency shifts, in addition, the carriers can never be perfectly synchronized. These random frequency errors in OFDM system distort orthogonality between subcarriers and thus intercarrier interference (ICI) occurs. A Number of methods have been developed to reduce this sensitivity to frequency offset

Adaptive Coherent Receiver Settings for Optimum Channel Spacing in Gridless Optical Networks

In this paper, we propose a novel circuit and system to optimize the spacing between optical channels in gridless (also called flexible-grid or elastic) networking. The method will exploit the beginning-of-life link margin by enabling the channel to operate in super-Nyquist dense wavelength division multiplexing mode. We present the work in the context of software-defined networking and high-speed optical flexible-rate transponders. The clock recovery scheme allows the mitigation of jitter by decoupling the contribution of high-jitter noise sources from the clock recovery loop. The method and associated algorithm are experimentally verified where a spectrum gain of up to 2 GHz in spacing between two channels in the Media Channel (MC) is obtained compared to conventional clocking strategies. We showed that the improvement is equivalent to increasing throughput, in a data-center interconnect scenario, by up to 300 giga-bits per second per route.