Wyniki wyszukiwania - BazTech

1

Effect of ultrasonic pre-treatment on coal slime flotation

Lv Wenbao, Chen Jun, Min Fanfei, Hou Baohong, Liu Chunfu

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 1

173--183

EN

Combined with the characteristics of flotation feed originating from China’s Panyidong Coal Preparation Plant, the ash, zeta potential, X-ray fluorescence spectroscopy and contact angle test were used to study changes in the surface properties of flotation feed under ultrasonic pre-treatment, and its effect on flotation of coal slime. Results show that Preferred pre-treatment process is ultrasonic secondary treatment, ultrasonic secondary pre-treatment can remove most of the high-ash fine mud for instance kaolinite, montmorillonite and quartz in the coal slurry, reduce the surface electronegativity of coal particles, and increase the contact angle of coal particles. Thus, the concentrate ash content decreases to 13%, the recovery rate, yield of flotation concentrate and combustible matter recovery reach 92.6%, 90.9% and 97.6%, respectively.

2

Effect of grinding media on the flotation of copper-activated marmatite

Long Tao, Chen Yao, Shi Juanjuan, Chen Wei, Zhu Yangge, Zhang Chonghui, Bu Xianzhong

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 2

229--237

EN

How to avoid the shortage of floatability and non-purpose flotation in marmatite flotation is a big problem. This paper innovatively studies how to reduce these two negative phenomena from the perspective of grinding media. The effects of steel and stainless-steel balls on the flotation performance of copper-activated marmatite were investigated mainly through flotation tests, redox potential measurements, ion concentration tests, and XPS and FT-IR spectrum studies. The flotation results showed that the floatability of copper-activated marmatite remarkably decreased by using the steel ball in the grinding process, but it had a mere influence when stainless-steel medium was used. Redox potential measurements showed that the grinding environment of stainless-steel medium could exhibit a higher oxidizing potential than the steel grinding environment. Results from FTIR, XPS, and ion concentration measurements demonstrated that more ferric ions existed on the copper activated marmatite surface in the steel grinding environment than that in the stainless-steel environment. Ferric ions could further hinder the activation effect of copper ions on marmatite and result in decreased marmatite flotation. This research could potentially explain the mechanism of ferric ions in the grinding process, and it can be utilized to improve the flotation performance of marmatite ore through selecting suitable grinding media in ball mill operations.

3

A survey of subpixel edge detection methods for images of heat-emitting metal specimens

Fabijańska A.

International Journal of Applied Mathematics and Computer Science

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2012

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Vol. 22, no. 3

695-710

EN

In this paper the problem of accurate edge detection in images of heat-emitting specimens of metals is discussed. The images are provided by the computerized system for high temperature measurements of surface properties of metals and alloys. Subpixel edge detection is applied in the system considered in order to improve the accuracy of surface tension determination. A reconstructive method for subpixel edge detection is introduced. The method uses a Gaussian function in order to reconstruct the gradient function in the neighborhood of a coarse edge and to determine its subpixel position. Results of applying the proposed method in the measurement system considered are presented and compared with those obtained using different methods for subpixel edge detection.

4

Fabric mechanical-surface properties of compression hosiery and their effects on skin pressure magnitudes when worn

Liu R., Kwok Y.-L., Li Y., Lao T. T.

Fibres & Textiles in Eastern Europe

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2010

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Vol. 18, no. 2 (79)

91--97

EN

Compression hosiery (CH) is one kind of mechanical therapeutic approach for the prophylaxis and treatment of venous disorders in the lower limbs. Their compression functional performance and comfort sensations are largely related to their material properties. The objective of this study was to comprehensively investigate the mechanical and surface properties of CH fabrics and their effects on corresponding skin pressure magnitudes in practical application. The mechanical testing of the material and skin pressure objective measurements applied to different kinds of CHs with four pressure levels were carried out using the Kawabata Standard Evaluation System and Multichannel skin pressure measuring system. This study shows that significant differences in material properties existed in CH fabrics with different pressure levels. Tensile energy (WT), tensile strain (EM), shearing stiffness (G) and bending rigidity (B) are key mechanical material indices, significantly correlative to skin pressure magnitudes; CHs fabrics with higher levels of pressure were rougher, stiffer and had less extensibility, but they had better dimensional stability. Significant differences in tensile, compression and surface properties existed between CHs fabrics in series A and those in B. The hosieries in series A produced more linear correlations between the key material indices and skin pressure magnitudes, which can be attributed to their fabrics having a smoother surface, greater elasticity, resilience and better dimensional stability. Moreover, proper surface properties of the material and hose design may enhance the pressure functional performance of compression hosiery products.

PL

Pończochy uciskowe są jednym z rodzajów mechanicznej terapeutyki stosowanej w profilaktyce i leczeniu chorób żylnych kończyn dolnych. Działanie ich zależy w dużej mierze od zastosowanego materiału. Celem badania było określenie właściwości mechanicznych i powierzchniowych pończoch i wpływu wywieranego ciśnienia w praktyce. Badania wykonano dla czterech poziomów ciśnienia przy użyciu systemu Kawabata i wielokanałowego układu mierzenia ciśnienia. Wykazano, że występują istotne różnice przy stosowaniu rożnych materiałów przy różnych poziomach ciśnienia. Ważnymi czynnikami wpływającymi na wielkości ucisku skóry są energia i odkształcenie przy naprężaniu oraz sztywność ścinania i zginania. Stwierdzono, że pończochy uciskowe o wyższym poziomie wywieranego ciśnienia były mniej delikatne, sztywne i wykazywały mniejszą rozciągliwość ale miały lepszą stabilność wymiaru. Przebadano różne serię wyrobów pończoszniczych i określone różnice pomiędzy nimi.