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排序方式: 共有9626条查询结果,搜索用时 31 毫秒
991.
Al7075 hybrid composites reinforced with varying weight percentage (0 wt.%, 5 wt.%, 10 wt.%, 15 wt.%) of each of garnet and fly ash were fabricated and characterized for their comparative wear assessment. The sliding wear test was conducted on a reciprocating tribometer in dry medium under the working conditions of applied normal load (2 N, 4 N, 6 N, 8 N), sliding velocities (0.04 m/s, 0.08 m/s, 0.12 m/s, 0.16 m/s), sliding distance (20 m, 40 m, 60 m, 80 m) and working temperature (25 °C, 50 °C, 75 °C, 100 °C). The experiments were performed as per steady‐state condition and Taguchi (L25) orthogonal array design to evaluate specific wear rate of the Al7075 hybrid composites. The finding of results indicated that the wear rate was decreased with the increase in the filler content in both the case of garnet and fly ash reinforced Al7075 hybrid composites. The results from Taguchi experiments suggested that the filler content and load were the most significant factors affecting wear behavior of composites while temperature and sliding distance are the least significant factors. Also, the garnet reinforced Al7075 hybrid composite indicated less specific wear rate as compared to that of fly ash reinforced Al7075 hybrid composite. 相似文献
992.
以铝灰渣和废盐酸为原料,通过酸溶法制备聚合氯化铝,考察了原料配比、反应温度、反应时间、熟化温度、熟化时间等因素对聚合氯化铝性能的影响,并对最佳工艺参数条件下制备的聚合氯化铝进行红外光谱分析。结果表明,铝灰渣和废盐酸制备聚合氯化铝的最佳工艺参数为:原料配比为m∶V1∶V2=20∶55∶80,反应温度为85℃,反应时间为3.5 h,熟化温度为80℃,熟化时间为42 h;在此条件下,制备的聚合氯化铝中氧化铝质量分数为8.15%,盐基度为35.6%;红外光谱分析表明合成的聚合氯化铝中存在聚合态铝和羟基结构。 相似文献
993.
《Advanced Powder Technology》2022,33(1):103385
The transient multiphase model with the Eulerian-Eulerian approach based on the Two-Fluid Model (TFM) was executed to simulate the bubbling regime’s hydrodynamics of bed material in the fluidized bed using three different drag models. Coal ash particles having three different sizes were taken in bed for fluidization under cold conditions. The bubbling regime's superficial velocities were acquired from experimentations and used as inlet velocities during Computational Fluid Dynamics (CFD) simulation of a 2-Dimensional fluidized bed. The Syamlal-O'Brien, Gidaspow and Wen-Yu drag models were considered in this study, and their effects on the bed hydrodynamics were discussed. The study emphasized the suitability of drag models for the coal ash particles. The drag force was not adequate and showed a negligible effect on particles irrespective of the high inlet velocity displayed by the Gidaspow model. The other two drag models predicted sufficient drag, but there was more intensity in Syamlal-O'Brien than in the Wen-Yu model. The Syamlal-O'Brien model resembled more physical fluidization occurrences for smaller and larger sized coal ash particles. This study also supports the hydrodynamics of the Geldart-D type particles. 相似文献
994.
T. Rajmohan 《Particulate Science and Technology》2019,37(1):21-30
Particle-filled polymer composites have become attractive because of their wide applications and low cost. Carbon fiber reinforced polymer (CFRP) is well known as a difficult-to-cut material, which has very strong physical and mechanical characteristics. Machining of carbon fiber reinforced composites is essential to have functional upshots, out of which drilling is the key operation needed for fabrication. In this paper Taguchi L27 experimental design is coupled with grey relational analysis (GRA) to optimize the multiple performance characteristics in the drilling of fly ash-filled carbon fiber reinforced composites. Experiments were conducted on a vertical machining center, and Taguchi L27 experimental design was chosen for the experiments. The drilling parameters, namely spindle speed, feed rate, drill diameter and wt% of fly ash, have been optimized based on the multiple performance characteristics including thrust force, surface roughness, and delamination. The GRA with multiple performance characteristics indicates that the wt% of fly ash and drill diameter are the most significant factors that affect the performance. Experimental results have shown that the performance in the drilling process can be improved effectively by using this approach. 相似文献
995.
Ting Yang Caiyun Han Hang Liu Liu Yang Dekun Liu Jie Tang Yongming Luo 《Advanced Powder Technology》2019,30(1):199-206
Na-X zeolite was successfully prepared from low aluminum coal fly ash (LACFA) via fusion-hydrothermal treatment. The influence of various synthesis parameters was investigated, including aluminum additives (AlCl3·6H2O, Al(NO3)3·9H2O, AlF3·3H2O and NaAlO2), dosages of NaAlO2, weight ratio of LACFA/NaOH, crystallization temperature and time. The results indicated that the addition of Al species played a key role in the synthesis process of purity Na-X zeolite, and the corresponding relative crystallinity of the obtained samples was in the order of Na-X zeolite(Al)???Na-X zeolite(Cl)?>?Na-X zeolite(N)?>?Na-X zeolite(F) (Here, “Al”, “Cl”, “N” and “F” represent NaAlO2, AlCl3·6H2O, Al(NO3)3·9H2O and AlF3·3H2O, respectively). And the optimal operating conditions were: the weight ratio of LACFA/NaOH?=?0.83, short crystallization time 360?min, low crystallization temperature 90?°C and 0.038?mol NaAlO2. Additionally, X-ray fluorescence (XRF), X-ray powder diffraction (XRD), Fourier Transforms Infrared (FT-IR) and Scanning Electron Microscopy (SEM) were employed to determine the resultant samples. Based on the results of As(V) adsorption experiment, the experimental data was suitable fitted by Freundlich adsorption isotherm model, and the theoretical maximum adsorption capacity was 27.79?mg/g at pH?=?2.14. The kinetics studies suggested that “surface reaction” was the rate-determining step of adsorption process, and the thermodynamics studies indicated that the adsorption process was spontaneous and endothermic. These results deemed that the LACFA was suitable for preparing Na-X zeolite(Al), and the obtained Na-X zeolite(Al) was served as a promising adsorbent to remove As(V) from acid wastewater. 相似文献
996.
Fly ash is milled for 0, 30 and 90?min and used to study the role of particle size on the kinetics of geopolymer formation. The increase in particle fineness is very prominent in the initial milling stage, and then slows down due to agglomeration effect of finer fraction. The fly ash geopolymerization kinetics and its mechanism is determined using heat of reaction data measured by isothermal conduction calorimeter. The improvement in reaction rate with milling is correlated with the median particle size of the fly ash. The apparent activation energy decreases with size reduction because finer fractions are more prone to alkali activation. Although the kinetics changes with particle fineness, but no alternation is detected in the reaction mechanism, governed by nucleation and growth. The apparent activation energy evaluated by rate method is showing three major steps of geopolymerization such as dissolution, gel formation and restructuring. 相似文献
997.
998.
用均匀设计方法对掺超细粉煤灰配制高强喷射混凝土进行研究,探索水灰比,灰砂比,粉煤灰细度三个因素对1d,3d,7d,28d强度四个考核指标的影响规律,优化组合后,配制成早期和后期强度都很高的粉煤灰高强喷射混凝土。 相似文献
999.
提出一种基于改进果蝇优化算法(Improved Fruit fly Optimization Algorithm,IFOA)的压电精密定位平台迟滞特性的Bouc-Wen模型参数辨识方法。通过引入交叉因子和自适应搜索步长,IFOA可有效实现全局搜索与局部优化的动态平衡,并通过一种新的搜索策略提高整体搜索效率和优化精度。将IFOA应用于压电精密定位平台迟滞Bouc-Wen模型的参数辨识。实验辨识结果验证了该方法的有效性和潜力。 相似文献
1000.
根据柔性作业车间调度问题的特点,针对不同生产效率的并行设备,以完工时间最小化为目标建立优化模型,提出了混合果蝇优化算法和遗传算法的两阶段组合算法(FOA-GA). 在嗅觉阶段,通过局部路径搜索技术进行生产路径寻优;在视觉阶段,结合遗传算法的交叉和竞争机制,进行个体间的信息交换,利用寻优变异算子和常规变异算子进行两部分变异,再引入自适应动态转移算子进行调整以加快收敛速度. 在生产实例中,将FOA-GA算法与果蝇优化算法和遗传算法的结果进行比较,证明了其可行性和有效性. 相似文献