Differential orthogonal frequency division multiplexing communication in water pipeline channels.

The problem of information transmission through water pipelines is addressed and a class of methods based on differentially encoded orthogonal frequency division multiplexing (OFDM) is proposed. Specifically, two methods are investigated; one based on conventional differential encoding with an estimation of the average time of arrival and another based on double encoding. Results show that the first approach improves performance in the low signal to noise ratio (SNR) region, while the second is better suited at high SNR.

Estimating acoustic wave dispersion in water pipelines using a single spatial measurement.

Estimating acoustic wave dispersion in pipelines filled with water is studied using theoretical analysis and laboratory experiments. Previous methods for experimentally estimating the dispersion of the propagating modes require multiple spatial measurements, making it difficult to measure. In this work the authors propose a method that utilizes only one spatial measurement using a singular value decomposition based approach.

The influence of pipeline thickness and radius on guided wave attenuation in water-filled steel pipelines: Theoretical analysis and experimental measurement.

The influence of pipeline thickness and radius on the attenuation of guided waves in water-filled steel pipelines is investigated using theoretical analysis and experimental measurement. Attenuations of individual axisymmetric modes in unburied water-filled steel pipelines are predicted by an analytical model under different pipeline radius-thickness ratios. Model predictions indicate that attenuation of the fundamental mode increases as the ratio rises.

A straightforward method for estimating the size of leaks in water pipelines using acoustic transients.

A straightforward explicit expression is derived for estimating the size and position of leaks in a water pipeline using the acoustic transient response. Experimental results are provided for a water pipeline with multiple leaks to demonstrate the usefulness and performance of the proposed approach. The form of the leak estimation expression can be further combined with an existing explicit expression derived for blockage detection.

Guided acoustic wave interaction with flanged junctions in water-filled steel pipelines.

The interactions of guided acoustic waves with pipelines and associated components has become a topic of interest due to their application in water pipeline condition assessment. In this paper, guided acoustic wave interactions with flanged junctions in a water-filled pipeline are investigated by an analytical model and experimental measurements. In the model, axial wavenumbers, displacement, and stress profiles of the main pipeline and flange junction components are calculated by an existing cylindrical waveguide analytical model.

An approximate inverse scattering technique for reconstructing blockage profiles in water pipelines using acoustic transients.

An approximate inverse scattering technique is proposed for reconstructing cross-sectional area variation along water pipelines to deduce the size and position of blockages. The technique allows the reconstructed blockage profile to be written explicitly in terms of the measured acoustic reflectivity. It is based upon the Born approximation and provides good accuracy, low computational complexity, and insight into the reconstruction process.

Propagation of monopole source excited acoustic waves in a cylindrical high-density polyethylene pipeline.

Acoustic wave propagation (up to 50 kHz) within a water-filled high-density polyethylene (HDPE) pipeline is studied using laboratory experiments and theoretical analysis. Experiments were carried out in a 15 m length of cylindrical HDPE pipeline using acoustic transducers to acquire signals uniformly spaced along the axis of the pipe. By proposing the use of the iterative quadratic maximum likelihood algorithm to this experimental configuration, wavenumbers, attenuations, and mode amplitudes could be accurately extracted from the measurement data.

Modeling Contrast-Imaging-Assisted Optimal Targeted Drug Delivery: A Touchable Communication Channel Estimation and Waveform Design Perspective.

To maximize the effect of treatment and minimize the adverse effect on patients, we propose to optimize nanorobots-assisted targeted drug delivery (TDD) for locoregional treatment of tumor from the perspective of touchable communication channel estimation and waveform design. The drug particles are the information molecules; the loading/injection and unloading of the drug correspond to the transmitting and receiving processes; the concentration-time profile of the drug particles administered corresponds to the signaling pulse. Given this analogy, we first propose to use contrast-enhanced microwave imaging (CMI) as a pretherapeutic evaluation technique to determine the pharmacokinetic model of nanorobots-assisted TDD.