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1

Mechanical performances of rock-like disc containing circular inclusion subjected to diametral compression

Chang X., Tang J., Wang G., Tang C.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 2

356--370

EN

This paper presents a numerical investigation of cracking behaviour of rock-like disc containing one circular inclusion subjected to diametral compression, which is validated by physical tests in terms of the crack patterns and stress–strain responses. The numerical results indicate that if the inclusion strength is higher or close to the matrix strength, one dominated crack can form to split the disc into two parts. Otherwise, the crack branches can be observed besides the dominated crack. The inclusion eccentricity has important influences on the crack pattern of the rock disc. If the inclusion strength is lower than the matrix strength, the horizontal eccentricity can induce to a horizontal crack. The length of the horizontal crack is close related to the eccentricity that a higher eccentricity can lead to a longer horizontal crack. The vertical eccentricity can result in crack branch, which becomes shorter as the eccentricity increases. If the inclusion strength is higher than the matrix, the horizontal and vertical eccentricity cannot lead to crack branches and only one dominated crack can be observed. The disc nominal strength increases by increasing the horizontal or vertical eccentricity both for cases of the inclusion strength lower and greater than the matrix.

2

Experimental and optimization design of offshore drilling seal

Zhang Y., Zhang X., Chang X., Wu Q.

Polish Maritime Research

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2017

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S 3

72--78

EN

Three-cone bit is the key equipment in the exploration of the oil in offshore drilling and exploration, the bearing system and the seal system are the critical components for the bit. Especially in the offshore drilling environment, the seal design need to be carefully considered. A multi-objective optimization design including orthogonal design method and F-test with finite element analysis for a three-cone bit seal is proposed. Firstly, the calculation method of optimization targets are given, including the minimization of maximum contact pressure and leakage rate analyzed by ANSYS and MATLAB respectively, to maximize seal life and reliability. Then, an orthogonal experiment approach is used to investigate the effects of the eleven parameters on the seal performance, and the influence degrees of the seal factors on the optimization targets have been confirmed by F-test, and the reasonable factors can be determined by the trend of the targets. Finally, in order to validate the analysis results, a new seal was designed and tested on a seal tester compared to the previous seal. In this test, the seal maximum interface temperature that reflects the position of maximum contact pressure can be obtained by using three high precision thermocouples. Both the experiment results and the numerical analyses proved that the maximum contact pressure and leakage rate of the improved seal have been reduced compared to the previous.

3

Combining Multiple Sound Sources Localization Hybrid Algorithm and Fuzzy Rule Based Classification for Real-time Speaker Tracking Application

Ibala C, Astapov S, Bettens F, Escobar F, Chang X, Valderrama C, Riid A

International Journal of Microelectronics and Computer Science

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2013

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Vol. 4, nr 1

12--25

EN

This work present a novel approach to track a specific speaker among multiple using the Minimum Variance Distortionless Response (MVDR) beamforming and fuzzy logic ruled based classification for speaker recognition. The Sound sources localization is performed with an improve delay and sum beamforming (DSB) computation methodology. Our proposed hybrid algorithm computes first the Generalized Cross Correlation (GCC) to create a reduced search spectrum for the DSB algorithm. This methodology reduces by more than 70% the DSB localization computation burden. Moreover for high frequencies Sound sources beamforming, the DSB will be preferred to the MVDR for logic and power consumption reduction.

4

In-situ automatic observations of ice thickness of seas

Dou Y., Chang X.

Metrology and Measurement Systems

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2012

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Vol. 19, nr 3

583-592

EN

Ice thickness is one of the most critical physical indicators in the ice science and engineering. It is therefore very necessary to develop in-situ automatic observation technologies of ice thickness. This paper proposes the principle of three new technologies of in-situ automatic observations of sea ice thickness and provides the findings of laboratory applications. The results show that the in-situ observation accuracy of the monitor apparatus based on the Magnetostrictive Delay Line (MDL) principle can reach š2 mm, which has solved the "bottleneck" problem of restricting the fine development of a sea ice thermodynamic model, and the resistance accuracy of monitor apparatus with temperature gradient can reach the centimeter level and research the ice and snow substance balance by automatically measuring the glacier surface ice and snow change. The measurement accuracy of the capacitive sensor for ice thickness can also reach š4 mm and the capacitive sensor is of the potential for automatic monitoring the water level under the ice and the ice formation and development process in water. Such three new technologies can meet different needs of fixed-point ice thickness observation and realize the simultaneous measurement in order to accurately judge the ice thickness.

5

Preconcentration and separation of Zn2+ using surface zinc(II) imprinted functionalized silica gel sorbent

He Q., Chang X., Zheng H., Jiang N., Hu Z., Zhai Y.

Chemia Analityczna

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2006

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Vol. 51, No. 5

715-725

EN

Zinc(II) imprinted amino-functionalized silica gel sorbent was synthesized applying surface-imprinting technique in order to preconcentrate and separate Zn2+ prior to its determination by inductively coupled plasma optical emission speclrometry (1CP-OES). Compared to traditional solid sorbents and non-imprinted sorbent, zinc(U)-irnprinted sorbent has higher selectivity and adsorption capacity towards Zn2+. Maximum static adsorption capa cities of ion-imprinted and non-imprinted sorbent towards Zn2+ were 12.98 mg g-1 and 4.36 mg g -1, respectively. The largest separation factor for zinc(II) imprinted sorbent towards Zn+2 in the presence of Hg+2 was higher than 188. Relative selectivity coefficient (&alfa;r) values for Zn+2 Hg+2 pair were 15.5 and 13.8-both greater than 1. Distribution coefficient (D) valuesofzinc(II) imprinted polymers to wards Zn2+ were greatly larger than those for Hg+2 . Detection limit (3 σ) of the method was 0.29 μg L-1 and relative standard deviation equalled 2.6% for eight replicate determination of 10 μg of Zn+2 in 200 mL-in-volume water sample. The proposed method was applied to the determination of trace zinc in biological and water samples with satisfactory results.

PL

Zsynletyzowano sorbent krzemionkowy do którego wprowadzono grupy aminowe z dopasowanym molekularnie Zn(II) stosując technikę dopasowania powierzchniowego. Sorbent . został zastosowany do wstępnego zatężenia i oddzielania Zn2+ przed jego oznaczaniem za pomocą spektometrii emisyjnej z plazmą sprzężoną indukcyjnie (ICP-OES). W porównaniu do tradycyjnych sorbentów oraz tego samego sorbentu „bez dopasowania molekularnego'', sorbent „z dopasowaniem molekularnym względem Zn(tl)" wykazuje lepszą selektywność i wyższą zdolność sorpcyjną względem 72+. Maksymalne zdolności sorpcyjne względem cynku sorbentu „z dopasowaniem" i „bez dopasowania molekularnego" wynosiły odpowiednio: 12.98 mg g-1 oraz 4.36 mg g-1. Największy współczynnik rozdzielenia jonów Zn+2 i Hg+2 w przypadku jonitu „z dopasowaniem molekularnym względem Zn(II)'' przewyższał 188. Względny współczynnik selektywności określający na ile współczynnik rozdzielenia pary Zn+2/Hg+2 w przypadku sorbentu ,.z dopasowaniem względem Zn(II)" jest lepszy niż w przypadku sorbentu ,,bez dopasowania został wyznaczony jako 15.5 lub 13.8 a więc był znacznie większy niż 1. Współczynniki podziału (D) dla jonitu z dopasowaniem Zn(II)były znacznie wyższe dla Zn+2 niż dla Hg+2. Granica wykrywalności (3σ) metody wyniosła 0.29 μ.g L-1 a względne odchylenie standardowe obliczone z ośmiu kolejnych oznaczeń 10 μg Zn+2 w 200 mL próbce wody wynosiło 2.6%. Zaproponowaną metodę zastosowano z powodzeniem do oznaczania śladów cynku w materiałach biologicznych i próbkach wody.