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1

The nonlinear oil–water two-phase flow behavior for a horizontal well in triple media carbonate reservoir

Wang Y., Tao Z., Chen L., Ma X.

Acta Geophysica

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2017

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Vol. 65, no. 5

977--989

EN

Carbonate reservoir is one of the important reservoirs in the world. Because of the characteristics of carbonate reservoir, horizontal well has become a key technology for efficiently developing carbonate reservoir. Establishing corresponding mathematical models and analyzing transient pressure behaviors of this type of well-reservoir configuration can provide a better understanding of fluid flow patterns in formation as well as estimations of important parameters. A mathematical model for a oil-water two-phase flow horizontal well in triple media carbonate reservoir by conceptualizing vugs as spherical shapes are presented in this article. A semi-analytical solution is obtained in the Laplace domain using source function theory, Laplace transformation, and superposition principle. Analysis of transient pressure responses indicates that seven characteristic flow periods of horizontal well in triple media carbonate reservoir can be identified. Parametric analysis shows that water saturation of matrix, vug and fracture system, horizontal section length, and horizontal well position can significantly influence the transient pressure responses of horizontal well in triple media carbonate reservoir. The model presented in this article can be applied to obtain important parameters pertinent to reservoir by type curve matching.

2

Rough Approximation Operators in Group Mapping and Their Applications to Coding Theory

Xu J., Qiu R., Tao Z.

Fundamenta Informaticae

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2016

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Vol. 145, nr 1

93--109

EN

This paper focuses on rough approximation operators in group mapping. The relationships between rough set theory and group theory are considered from a novel perspective. The necessary and sufficient conditions for the upper approximation and lower approximation of a group to be groups are analyzed. In addition, the homomorphism and isomorphism between two groups which have related upper or lower approximations are investigated. Finally, the applications of rough approximation operators in group mapping to coding theory are developed.

3

New Approach for Dyeing and UV Protection Properties of Cotton Fabric Using Natural Dye Extracted from Henna Leaves

Omer K. A., Tao Z., Seedahmed A. I.

Fibres & Textiles in Eastern Europe

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2015

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Vol. 23, no. 5 (113)

60--65

EN

A new approach for the dyeing and UV protection of cotton fabric using Henna extract was investigated. In this study, 3-chloro-2-hydroxy propyl, trimethylammonium chloride was used to substitute metallic mordants (heavy-metal salts) in the pre-treatment of cotton fabric. This will eventually prevent heavy metal pollution as well as facilitate dyeing without the addition of salt. Cationised cotton fabrics were dyed with Henna extract at different dyeing temperatures for different dyeing times. Colour strength, fastness properties (washing, rubbing and light), UV-blocking and tensile strength were investigated. Cationised fabric dyed with Henna extract exhibited outstanding enhancement in UV protection with minimal impact on the tensile strength. Enhancement or decrement in UV protection and colour strength was found to be governed by the dyeing temperature and dyeing time.

PL

W prawadzonych badaniach zastosowano chlorek 3-chloro-2-hydroxypropylo-trimetylooamonowy dla zastąpienia metalicznych zapraw (soli metali ciężkich) do wstępnej obróbki materiałów bawełnianych. Powinno to zapobiec zanieczyszczeniu ciężkimi metalami, jak również ułatwić barwienie bez dodatku soli. Kationizowane materiały bawełniane były barwione ekstraktem henny przy rożnych temperaturach i czasach barwienia. Badano intensywność koloru, odporność na pranie, tarcie i światło, jak również lokowanie promieniowania UV i właściwości wytrzymałościowe. Kationizowane materiały barwione za pomocą ekstraktu henny wykazywały wybitne zwiększenie barierowości UV przy minimalnym wpływie na wytrzymałość mechaniczną. Na zwiększenie lub spadek właściwości zabezpieczających przed UV i intensywność koloru miały wpływ temperatura i czas barwienia.

4

Speech Enhancement Based on the Multi-Scales and Multi-Thresholds of the Auditory Perception Wavelet Transform

Tao Z., Zhao H. M., Zhang X-J., Wu D.

Archives of Acoustics

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2011

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Vol. 36, No. 3

519-532

EN

This paper proposes a speech enhancement method using the multi-scales and multi-thresholds of the auditory perception wavelet transform, which is suitable for a low SNR (signal to noise ratio) environment. This method achieves the goal of noise reduction according to the threshold processing of the human ear’s auditory masking effect on the auditory perception wavelet transform parameters of a speech signal. At the same time, in order to prevent high frequency loss during the process of noise suppression, we first make a voicing decision based on the speech signals. Afterwards, we process the unvoiced sound segment and the voiced sound segment according to the different thresholds and different judgments. Lastly, we perform objective and subjective tests on the enhanced speech. The results show that, compared to other spectral subtractions, our method keeps the components of unvoiced sound intact, while it suppresses the residual noise and the background noise. Thus, the enhanced speech has better clarity and intelligibility.

5

A Lifting Wavelet Domain Audio Watermarking Algorithm Based on the Statistical Characteristics of Sub-Band Coefficients

Tao Z., Zhao H., Wu J., Gu J., Xu Y., Wu D.

Archives of Acoustics

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2010

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Vol. 35, No. 4

481-491

EN

In this paper, a new lifting wavelet domain audio watermarking algorithm based on the statistical characteristics of sub-band coefficients is proposed. First of all, an original audio signal was segmented and each segment was divided into two sections. Then, the Barker code was used for synchronization, the LWT (lifting wavelet transform) was performed on each section, a synchronization code and a watermark were embedded into the first section and the second section, respectively, by modifying the statistical average value of the sub-band coefficients. The embed strength was determined adaptively according to the auditory masking property. Experiments show that the embedded watermark has better robustness against common signal processing attacks than present algorithms based on LWT and can resist random cropping in particular.