Papers by Keyword: Removal Rate

Abstract: Test by establishing different embankment flowing systems studied the combination of different substrates and different plants purification efficiency and the effect on the stability of the efficiency of the flowing system. Results show that, the mixed matrix(loess, sand and brown loam) is more efficiency than the single matrix, especially for suspended solid (SS), ammonia (NH₃-N), total phosphorus (TP) removal, the removal rate is over 60%. Tall fescue (Festuca elata Keng ex E. Alexeev) is more suitable for the flowing system than perennial ryegrass (Lolium perenne L.). And, long running of the system is possible.

Abstract: Chemical mechanical polishing/ planarization (CMP) is a key technology for fabricating high-efficient semiconductor devices, and the CMP characteristics (removal rate and accuracy, etc.) is depended on the various consumables represented by slurry, polishing pad and dresser used in the CMP process. Currently, in the pad, there are many studies that have pointed the evaluation methodology and the correlation between the pad surface asperity and the CMP characteristics. On the other hand, the dresser is one of the most important consumables because the dresser can control the pad surface asperity, and the diamond grains electrodeposited dresser (diamond dresser) is frequently used. One drawback point of the diamond dresser is that the dressing performance declines owing to the deterioration of the diamond grains. Previously, we have developed a novel flexible fiber dresser that would ensure high performance and longer life of tools, and we have reported the fundamental characteristics by the flexible fiber dresser compared with that of the diamond dresser. In this paper, we will show the results of tool life evaluation of the flexible fiber dresser using a contact image analysis method. As a result, the flexible fiber dresser can be continuously used over 35 hours. Furthermore, the result of having examined the stability of the removal rate of a silicon wafer is reported. Therefore, we found that the flexible fiber dresser is one of the most effective dressing methods for the polishing pad.

Abstract: As a cost-effective technology, using biological treatment technology to treat tail water has been gradually promoted in and abroad. Biological treatment technology uses the organic combination of water ecosystem to remove the organic pollutants and pollutants such as N and P which cause water eutrophication. This paper takes Jiangyin City Xinqiao Town Sewage Treatment Plant as example to construct bio-ecological combined constructed wetlands system near natural river course to treat tail water from sewage treatment plant and investigates the removal efficiency of combination process for COD, ammonia, TN and TP in tail water. The research indicates that bio-ecological combined constructed wetlands system has good removal efficiency for pollutants in tail water. And the average removal rate of COD, ammonia, TN and TP are 29%, 31%, 18%, and 8%; the average effluent concentration of them are 35.54mg/L, 0.97mg/L, 10.77 mg/L, and 0.11 mg/L. The result exactly matches the first grade A standard of Urban Sewage Treatment Plant Pollutant Discharge Standard (GB18918-2002). It has great potential for tail water treatment and is suitable for rural regions. The research result provides both the data and theoretical basis for improvement of biological treatment technology of tail water from sewage treatment plant, and also provides direct theoretical basis and practical experience for promotion and research of wetlands ecosystem.

Abstract: Products such as parts of die sets and cutting tool inserts are normally produced with complex shapes in materials of high hardness and wear resistance such as ceramics. Electro discharge machining (EDM) can be used to manufacture complex shapes in high hardness materials, but the material should be conductive. Being conductive, Aluminum oxide (Al₂O₃) based ceramics represent a good alternative for manufacturing hard complex shape parts. However, the integrity of the produced surfaces and the material removal rate need to be investigated. A full factorial experimental design was used to investigate the effect of some selected process variables, namely; pulse-on time, pulse-off time, and pulse current on specific EDM performance measures. The considered performance measures are; crater diameter (D), material removal rate (MRR), and average roughness value (Ra). An analysis of variance (ANOVA) test was carried out to evaluate the experimental results. Empirical models have been developed using DESIGN EXPERT V.8 to predict the average crater diameter (D), material removal rate (MMR), and average roughness value (Ra). Machining conditions that should result in optimum process performance measures have also been considered.

Abstract: This paper deals with experimental investigations related to removal of manganese (II) from electrolytic manganese residues by using ozone as oxidant. Ozone was used in this study to oxidize manganese converting bivalent manganese to high valence states, the oxidized salts will precipitate as manganese oxides, that to reach the concentration of the pollutant under its limit values in water. Effects of reaction temperature, reaction contact time and initial pH value on the manganese (II) removal were investigated. The results indicated that the removal rate exceeded 99.9 percent, and the manganese (II) in solution was lower than 0.1 mg·L^-1 under the conditions of reaction temperature 45 °C, reaction contact time 40 min and initial pH 12.

Abstract: this article through the analysis and application of special-shaped thin-wall aluminum alloy parts, discusses the parts processing technology, in order to solve the problem of deformation and low machining efficiency, provide a reference for machining similar parts.

Abstract: Based on the equipment of integrated constructed wetlands (ICWs) with independent intellectual property rights. Plant biological membrane system (PBMS) was constructed to purify nitrogen of sanitary sewage. PBMS includes palm silk, non-woven and floating plant (Trifolium repens L.). Total nitrogen (TN), ammonia nitrogen (NH₃-N) was investigated to evaluate the effects of the layered purification and resistance to the outside impact. The results showed that layered purification occurred along the flowing vertical direction. The average removal rate of TN, NH₃-N and total dissolved solids was 65.6%, 60.7% and 38.7%, respectively. The TN and NH₃-N removal load of the lower, middle and upper layer were 1.0, 0.8, 0.7g/ (m².d) and 0.8, 0.8, 0.3g/ (m².d), respectively. The higher concentration of inflow the stronger resists impact load capability. The TN and NH₃-N average removal load of the lower, middle and upper layer were 4.1, 1.88, 1.57 times and 3.13, 1.25, 1 time than those of the stable phase, respectively.

Abstract: In the plain-lake area of south China, aquaculture and plantation of aquatic commercial crop are very common. In order to realize water quality improvement for aquaculture pond and reuse of the nutrients, it is essential to establish an integrated system that constitute aquaculture pond and plant purifying pond which are linked by necessary farmland works. In the study, the connection between fishpond and lotus pond was established mainly by water pipe and water suction pump. When lotus pond is used for purifying fishpond water, using water pump draw water from fishpond into lotus pond, then experiments of water retention and subsurface flow on the lotus pond were done in the several growth stages of lotus root. During the experiments taking water samplings at the inlet and outlet which were installed at lotus pond to determine the relevant water quality indicators, analysis showed that: TP, TN, NH₄⁺-N, NO₃^――N, NO₂^――N and COD_Mn contained in aquaculture water may effectively remove as the water stay at lotus pond for a certain time, the removal rate of the above-mentioned substances increases with the increase of retention period of the aquaculture water standing in lotus pond; there are some regularity when fishpond water is purified by surface flow in lotus pond, the removal rate for TP and TN in dormant stage of lotus root is more than that in adult-plant stage and the effect in adult-plant stage is more than that in rooting stage, and for NH₄⁺-N, NO₃^――N, NO₂^――N and COD_Mn the removal rate in adult-plant stage is more than that in dormant stage and the effect in dormant stage is more than that in rooting stage; the more of the TP, TN, NO₃^――N and NH₄⁺-N is removed with the increase of the running time when fishpond water processed by surface flow in lotus pond, the removal rate of them arrives to 13.89%, 11.43%, 11.02% and 5.73% separately after the system running for 6 hours; compared with the contrast fishpond, the water quality of the fishpond combining with lotus pond is good obviously, where water quality indicators such as TP, NO₃^--N, TURB(turbidity) and SD(water transparency) arrive to significant improvement, meanwhile TN, NH₄⁺-N and COD_Mn get a marked improvement. On average, such a conclusion can be drawn that aquaculture in fishpond and plantation in lotus pond may be integrate, fishpond water may get an improvement by ex-situ purification of lotus pond, and meanwhile the combination makes it possible that the nutrients contained in fishpond water are recycled.

Abstract: Metoprolol (MET) is a common kind of Pharmaceuticals and personal care products (PPCPs), which belongs to a new type of organic micropollutants. And conventional water and wastewater treatment technology cannot remove the MET effectively, so it is necessary to adopt nanofiltration technology for advanced treatment. The influence factors on removal of Metoprolol (MET) in water by nanofiltration are mainly investigated in the study. According to the results, the removal rate of MET by nanofiltration all can reach more than 99% with the initial concentration increasing. Then the removal rate of MET by nanofiltration at different pressure values, pH, salt ionic strength conditions are also studied. The results have shown that the removal rate is increasing from 90.0% to about 99.0% while pressure goes up. When pH=5, the removal rate of MET by nanofiltration is slightly increasing. And the removal rate is decreasing from more than 98.0% to more than 92.0% with salt ionic strength increasing.

Abstract: Sapphire (α-Al₂O₃) single crystal combines many good mechanical and optical properties that make it become the material of choice in a variety of modern Hi-Tech applications The use of CMP technique can produce high quality surface finishes at low cost and with fast material removal rates. In CMP process, nanoabrasive is very important parameters in determining the removal rate. In this paper, the influence mechanism of nanoabrasive on sapphire substrate CMP was analyzed deeply. The main kinetics processing was discussed in detail. According to sapphire substrate properties, alkali slurry was chosen and the mix of SiO₂ and Al₂O₃ sol was selected as nanoabrasive, and the particle size was 20~30nm. The results show that adding nanoalumina with the concentration of 20ml / L in the main abrasive can make the chemical action balance with the mechanical action in the CMP process, so that the substrate removal rate is well improved, and the surface roughness can be reduced to 0.236nm by adjusting the process parameters and slurry ratio. Such data meets the super smooth requirement and the optimal sapphire surface can be gotten. So such slurry with mixed abrasive can be as rough polishing slurry and can improve the polishing efficiency.