Papers by Keyword: Particle

Abstract: An experimental study on the preparation of molybdenum disilicide (MoSi2) was conducted by self-propagating high-temperature synthesis (SHS) from elemental powder compacts with different pelletizing pressures (0, 50, 100 and 200MPa). The composition of test specimens is Mo:Si = 1:2. The results showed that the propagation time of the reaction front, the density of the combustion products, the particle size and the morphology of MoSi2 were significantly influenced by pelletizing pressure of the reactant compact. In addition, all the samples obtained with different pelletizing pressures were single-phase MoSi2.

Abstract: Present paper, introducing a new method of mechanical preparation of specific surfaces in a liquid medium by using unguided tools. All the presented work is originally approach based on the search of mechanics contact behaviour laws in a liquid medium. It promotes the operations of deburring and polishing, whilst causing a hardening, by varying the experimental conditions (material type, treatment time, presence or absence of chemical additions). This method was used for large dimensions pieces in order to treat the inner and outer surfaces.

Abstract: Industrial dust emission is one of the main sources of fine particle especially for PM2.5 in atmosphere. Filter media is the key component for baghouse. In the paper, several normal needle felt filters and membrane filter are studied through experiments. The performances of filter such as resistance, capture efficiency for total particle and number counting efficiency for fine particle are tested.The experimental results show that the resistance of filter increase after aging, the resisitance increasing rate of membrane filter is the smallest; The efficiencies for total particles of normal filter are above 99.9% at clean state, and 99.99% at stable state after aging; Although the filters have high efficiency for total particle, but the number counting efficiency for 10μm particle is 94%-99%, and 52%-92% for 2μm particles. New filters for fine particles are needed.

Abstract: Abstract. Objective: To explore the application of Coulter Multisizer in the experiment of medical equipment product particle detection through the Coulter method of particle content measurement. Methods: Analyze the particle content by Beckman Coulter Multisizer 3 produced by Beckman Company, and compare the particle content detection result of blank contrast solution and eluant. Conclusion: Coulter method and Coulter Multisizer have a great advantage on medical equipment product particle detection.

Abstract: Hysteresis effect of contact angle has an important impact on liquid bridges between sphere particles. This effect is not limited to increasing liquid volume of fixed particles. The hysteresis effect of contact angle is expressed by fixed liquid volume while the two sphere particles are in relative movement. The hysteresis effect of contact angle on the liquid bridge is also significant. In this paper, the hysteresis effect of contact angle on capillary forces of liquid bridges is analyzed when the two sphere particles are in relative movement. Results indicate that contact angle hysteresis effects on capillary force are significant.

Abstract: It tends to produce high-turbidity raw water during the initial period of typhoons or storms and affect the operation of the purifying system. In this research, the particles size (D98) in raw water was 100–125 μm; that in effluent water was <25 μm. When was under 8 ml/s, effluent water D98 was <10 μm. Flow ratio mitigation and the increase of overflow level can improve the particle removing ratio In aspect of particle size analysis, optimal operating conditions can be achieved setting an 8 ml/sec and 40cm overflow level and D98 grain size can be reduced to 6.25μm as well, particle size removal ratio will gradually climb with the increase of accumulated percentage so that it can reach 70 % for the respective effluent water under D50 and even becomes over 80 % under D98. When under D90, the removing ratio can even go beyond 90 % at an 8 ml/s of flow ratio. Therefore, the proposed pre-treatment reduces high turbidity due to the sudden increase of raw water to the barrier in front of the board.

Abstract: High-density circulating fluidized beds (CFB) differ in several respects from low-density CFB systems. In high-density CFB risers, solids move upward throughout the entire riser cross-section, and the net downflow of particles at the wall, a commonly observed feature of fast fluidized beds, is absent. Hence there exists a transition regime from the low density to high density CFB where the net particle motion in the vicinity of the wall is changing from downwards to upwards. This was confirmed by experiments carried in a dual-loop high-density CFB facility with concentric-tube heat exchanger installed in the riser. Local suspension-to-wall heat transfer coefficient and suspension temperature distribution below and above the heat exchange section were measured. Experimental results elucidated that particles move both upwards and downwards in the vicinity of the wall for the operation conditions studied. This alternation of direction leads to higher heat transfer coefficients at both ends of the heat exchange.

Abstract: In this research, the raw water presenting turbidity was sampled to simulate the change of the water quality. A barrier board was used to extend the flowing route and the level change of the overflow; carry out the pre-treatment of high-turbidity raw water. Particle detention time and the average flowing speed analyzed as well for comparing the removal effect with that in the physical field. The particle detention time is as follows: At 4-141 min, the operating time can be shortened; when this is less than 90 min, the effluent still can maintain a 50-88% turbidity removal rate and the water quality of the effluent can even drop to 530 NTU. During the test, most of the average flowing speed was within the operating scope of the rectangular Sedimentation Basin for which the removal rate was 61%-93% and the effluent turbidity was below 1,000 NTU and even up to the optimal 380 NTU. A total of 3 items meet the operating requirements of the Inclinometer Sedimentation Basin, presenting a 54%-72% removal rate and 1,000-1,650 NTU of effluent turbidity; and one item exceeds the operating requirements of the Inclinometer Sedimentation Basin, presenting a lowered 1,900 NTU of effluent turbidity from 3,800 NTU and a 50% removal rate. Large-size particles exist in the high-turbidity raw water, which tends to settle under the gravity effect during after a long-route flowing journey. For example, the turbidity of the influent is 4,300-5,300 NTU which was reduced to 920-750 NTU after the pre-treatment experiment presenting a 79-86% or higher removal rate.

Abstract: Gd_0.6BaB₉O₁₆: Eu³⁺_0.4 red phosphors were prepared by sol-gel technique. The different polyethylene glycols (PEGs) were added to control the particle size ofGd_0.6BaB₉O₁₆: Eu³⁺_0.4. The particle distribution and the relationship between the particle size and the luminescence properties of the phosphors were investigated. PEGs have no influence on the structure ofGd_0.6BaB₉O₁₆: Eu³⁺_0.4, but the particle size is changed with different molecular weight of PEGs. And the relative intensity of excitation peak and emission peak ofGd_0.6BaB₉O₁₆: Eu³⁺_0.4phosphor are reduced by adding PEG, due to the particle size effects.

Abstract: Hydraulic focusing technology is an important method in many researches about particles. But there is no reported direct real-time detection method to survey its stability. A novel and high resolution method is put forward, which is based on digital image processing technology to detect hydraulic focusing stability. And five parameters are designed to assess its stable performance. A set of experiments is implemented with different sample and buffer hydraulic focusing forming velocities, and the results and experimental error are discussed seriously. The conclusion can be drawn by the final experimental error analysis which is less than during all the detection course. It can be proved that this hydraulic focusing stability detection method based on digital image process technology has the advantages of the excellent precision, the fast processing speed and the good reliability.