Correspondence analysis and establishment of evaluation model of classification performance indices for a turbo air classifier

The operational parameters of a turbo air classifier including feeding speed, rotor cage's rotary speed and air inlet velocity affect its classification performance directly, such as cut size, classification precision, classification efficiency, fine powder yield, particle fineness and degree of dispersion. Current methods of optimizing operational parameters and improving the classification performance of a turbo air classifier are almost single objective decision only for one of the classification performance indices. In this paper, the multi‐objective programming (MOP) model on classification performance for a turbo air classifier is established to evaluate these performance indices comprehensively and achieve optimal classification performance. To minimize the effect of repeatability within these classification performance indices, correspondence analysis is applied to determine the evaluation indices of this MOP model. According to correspondence analysis on the fine talc classification experimental data as well as the calcium carbonate classification experimental data, there is a very strong correlation between cut size and D90; there is also a very strong correlation between cut size and fine powder yield. Thus D90 and fine powder yield are filtered out and they aren't discussed in the evaluation model. The variation coefficient method is introduced to calculate weights of the evaluation function, and the dimensionless transformation method is used to eliminate the effects of different dimension. Thus, the optimal solution among the experimental data is obtained through solving the evaluation function. For the talc classification experiments, the optimal operational parameter combinations are: the feeding speed is 40 kg · h^–1, the air inlet velocity is 5 m · s^–1 and the rotor cage's rotary speed is 1200 ? min^–1. The classification performance indices are: cut size is 16.5 μm, classification precision index is 0.59, Newton classification efficiency is 57% and degree of dispersion is 2.13. For the calcium carbonate classification experiments, the optimal operational parameter combinations are: the feeding speed is 92 kg · h^–1, the air inlet velocity is 12 m · s^–1 and the rotor cage's rotary speed is 1200 ? min^–1. The classification performance indices are: cut size is 31.4 μm, classification precision index is 0.74, Newton classification efficiency is 74% and degree of dispersion is 1.27. This evaluation model avoids the limitation of evaluation for the single classification performance index and incomplete information got by the means of single factor experiment of operational parameters. It also provides the quantitative evaluating criteria for classification performance of a turbo air classifier, which offers a theoretical basis for effective production. This multi‐objective programming optimizing method and evaluation model on classification performance can be applied to other dynamic air classifiers as well.     

水轮机调速系统暂态响应性能指标的计算

本文提供一套水轮机调速系统暂态响应性能指标的计算公式,可以分别对频率扰动和负载扰动时的工作情况进行计算。     

Optimisation of cobalt-based hardfacing in carbon steel using the fuzzy analysis for the robust design

In this paper, we present the application of the fuzzy logic analysis to a Taguchi orthogonal experiment for developing a robust model with high efficiency in multiple performance characteristics (MPCs) of the plasma transfer arc welding (PTAW) hardfacing process. It eliminates uncertain information and is a simple, effective, and efficient approach. A fuzzy logic system is used to simultaneously investigate relationships between various MPCs and to determine the efficiency of each trial of the Taguchi experiments. From the fuzzy inference process, we are able to determine the optimal setting of factor-levels for the MPCs. In addition, we also use the analysis of variance (ANOVA) to identify the significant factors, which coincide with findings from the fuzzy logic analysis and are found to account for about 79% of the total variance. Furthermore, a confirmation experiment of the optimal process is conducted, and it verifies that both individual performance characteristics and MPCs are successfully optimized and satisfy our desired levels of MPCs.     

3D Characterization of super-smooth surfaces of diamond turned OFHC copper mirrors

In this study, super-smooth surfaces of oxygen-free high-conductivity copper mirrors obtained by single point diamond turning were characterized with an atomic force microscope from the three-dimensional (3D) point of view. The machining conditions were also studied. A program developed in this study for a unified approach to 3D surface finish assessment proposed by the Commission of European Community was used to obtain the 3D parameters. The feed rate was changed from 0.2 to 2.0 μm per revolution and 0.3-3.0 μm per revolution, respectively, in two experiments. By 3D roughness characterization of these surfaces, the optimal feed rate was found to be 1.4 μm per revolution when cutting depth was 1 μm or 0.9-1.2 μm per revolution at a cutting depth of 2 μm, where an S_q of 2.6 and 2.3 nm could be obtained, respectively. The suggested 3D roughness characterization parameters may include S_q, S_sk, S_ku, S_tr, S_al, S_Δq, and one functional parameter, such as S_bi.     

Effects of high temperature and combustion on fluidized material attrition in a fluidized bed

This study investigated the effects of high temperature and combustion conditions on the attrition of fluidized material in a fluidized bed. Silica sand was fluidized in air at an atmospheric pressure between 873 K and 1,073 K. The operating parameters evaluated in investigating the attrition rate of fluidized material included particle size, temperature and both combustion and non-combustion conditions. Experimental results indicated that the total weight of attrition increased with increasing temperature and decreased with increasing particle size. The attrition was higher during the initial fluidization period than the later period, due to the loss of sharp corners and edges of the attrition particles. The initial and final attrition rates during combustion were higher than those in the non-combustion condition, because the heat and thermal shock were produced to increase attrition rate during incineration. Comparing the experimental data with previous correlations, that reveals a significant level of error in the prediction results from existing correlations. This error may occur because the experimental equations neglected the operating temperature and particle size.     

Spectral sensing of foliar water conditions in two co-occurring conifer species: Pinus edulis and Juniperus monosperma

Many fundamental ecosystem properties and dynamics are determined by plant water stress, particularly in dryland ecosystems where water is usually limiting. Indeed, under severe drought, plant water stress and associated insect infestations can produce landscape-scale mortality. Despite the fundamental importance of plant water stress in determining properties and dynamics at ecosystem and landscape scales, approaches for remotely sensing plant water stress are largely lacking, particularly for conifers. We evaluated the remotely sensed detection of foliar drought stress in two conifer species, Pinus edulis and Juniperus monosperma, which are co-dominants of extensive-juniper woodlands in North America, the first of which experienced extensive mortality in association with a recent drought. Needle spectra were made on these species in the field using an integrating sphere and portable spectrometer. Two indices of foliar water condition, plant water content (% of dry mass) and plant water potential, were compared to five spectral analyses: continuum removal of the 970 and 1200 nm water absorption features, the Normalized Difference Water Index (NDWI), the Normalized Difference Vegetation Index (NDVI), and the red edge wavelength position. For P. edulis, plant water content was significantly correlated with four of the five indices: NDVI (R²=0.71) and NDWI (R²=0.68) which exhibited stronger relationships than 970 nm continuum removal (R²=0.57) or red edge position (R²=0.45). All five indices were significantly correlated with P. edulis water content when trees undergoing mortality were included in analyses (R²=0.60-0.93). Although the correlations were weaker than for plant water content, plant water potential was significantly correlated with NDWI (R²=0.49), 970 nm (R²=0.44), NDVI (R²=0.35), and red edge (R²=0.34); again all five indices had significant relationships when trees undergoing mortality were included (R²=0.51-0.86). The relationships were weaker for J. monosperma: water content was significantly related to 970 nm (R²=0.50) and 1200 nm (R²=0.37) continuums and NDVI (R²=0.33), while water potential was related only to 1200 nm (R²=0.40). Our results demonstrate a critical link between plant physiological characteristics tied to water stress and associated spectral signatures for two extensive co-occurring conifer species.     

利用缓冲质子源制作LiNbO3光波导:光学特性及稳定性研究

利用缓冲质子源(苯甲酸中掺入一定量的苯甲酸锂)在Z切LiNbO3基底上制作了质子交换平面光波导，得到了不同掺杂摩尔分数(0．5％，1．0％和1．5％)的缓冲质子源质子交换波导的有效扩散系数及折射率分布。随着质子源中苯甲酸锂的摩尔含量逐渐增加，质子交换的有效扩散系数呈指数衰减，同时波导表面折射率增量线性递减。研究了有效折射率的稳定性特征，并与用纯苯甲酸制作的光波导进行了比较，发现利用缓冲质子源制作的LiNbO3光波导的稳定性明显优于纯苯甲酸制作的光波导。     

烧结燃料二次分加优化试验研究

为进一步探明燃料种类及其搭配，燃料粒度等对燃料二次分加效果的影响，就二次分加时，无烟煤与焦粉的搭配顺序，焦粉粒度对钒钛磁铁精矿烧结指标的影响进行了研究。找出了适宜的燃料种类（焦粉）及其适应的粒度范围。为燃料二次分加工艺优化工业性试验提供了依据。     

国际石油勘探开发项目经济评价指标体系与综合评价

从项目现金流分析、合同者(合作公司)现金流分析和参股者现金流分析的角度，考察了现有的国际石油勘探开发项目的经济评价指标，归纳总结出建立国际石油合作经济评价指标体系的7条原则，并在此基础上独立构建了一个新的指标体系。新的指标体系由15个指标构成，能够全面反映不同地区、不同财务制度下油田勘探开发项目的综合经济效益。最后结合一则实例，展示了在该指标体系的基础上进行多方案综合评价和优选的方法和步骤。