Comprehensive analysis of minimum grain size in pure aluminum using friction stir processing

A friction stir processing (FSP) technique has been developed for use with aluminum and magnesium alloys, with the goal of high-strain-rate processing. In this study, we treat the microstructures of aluminum samples, of three levels of purity, manipulating their grain sizes, making them finer, using FSP. Grain sizes decreased with an increase in the Zener-Hollomon parameter, at all purity levels. However, the recrystallized grain of FSP-ed ultra-high-purity (99.999%) aluminum was particularly large, compared to the grain sizes of lower-purity (99% and 99.99%) aluminum, when subjected to the same processing conditions. The grain size reached a certain minimum value at high-strain-rates of processing, which we report for each purity level herein.     

Decision tree approach for classification and dimensionality reduction of electronic nose data

This paper presents a decision tree approach using two different tree models, C4.5 and CART, for use in the classification and dimensionality reduction of electronic nose (EN) data. The decision tree is a tree structure consisting of internal and terminal nodes which process the data to ultimately yield a classification. The decision tree is proficient at both maintaining the role of dimensionality reduction and at organizing optimally sized classification trees, and therefore it could be a promising approach to analyze EN data. In the experiments conducted, six sensor response parameters were extracted from the dynamic sensor responses of each of the four metal oxide gas sensors. The six parameters observed were the rising time (T_r), falling time (T_f), total response time (T_t), normalized peak voltage change (y_p,n), normalized curve integral (C_I), and triangle area (T_A). One sensor parameter from each metal oxide sensor was used for the classification trees, and the best classification accuracy of 97.78% was achieved by CART using the C_I parameter. However, the accuracy of CART was improved using all of the sensor parameters as inputs to the classification tree. The improved results of CART, having an accuracy of 98.89%, was comparable to that of two popular classifiers, the multilayer perceptron (MLP) neural network and the fuzzy ARTMAP network (accuracy of 98.89%, and 100%, respectively). Furthermore, as a dimensionality reduction method the decision tree has shown a better discrimination accuracy of 100% for the MLP classifier and 98.89% for the fuzzy ARTMAP classifier as compared to those achieved with principle component analysis (PCA) giving 81.11% and 97.78%, and a variable selection method giving 92.22% and 93.33% (for the same MLP and fuzzy ARTMAP classifiers). Therefore, a decision tree could be a promising technique for a pattern recognition system for EN data in terms of two functions; as classifier which is an optimally organized classification tree, and as dimensionality reduction method for other pattern recognition techniques.     

创新光源环球型灯芯节能灯

专利技术环球形灯芯电光源(专利号:ZL 2010 2 0628559.6),本发明其环形阴极居于其环形阳极内腔的中央,阴极起动损伤极小。本发明其环形阴极涂覆有稀土纳米电子陶瓷。本发明比白炽灯泡寿命提高60倍,比节能灯提高10倍。且制造成本大幅度降低。     

HPS3016型混凝土喷射机械手

随着国内隧道和高速公路的建设加快,对于混凝土喷射设备的需求也日益增加,国外进口设备价格昂贵,增加了投资成本.HPS3016型混凝土喷射机械手采用模块化设计,性能稳定,操作简单,应用广泛.详细介绍该机的功能、相关技术参数、主要组成部件等.该机在使用性能上完全达到或超过同类产品,节约了工程投资,具有良好的经济效益和社会效益...     

西门子交流伺服驱动器性能的调试与优化

伺服系统是数控机床最重要的组成部分之一,其动态特性直接影响到数控机床的加工精度.Simocom_U伺服调试软件能够根据伺服电机实际拖动的机械部件,对伺服驱动器的参数进行自动调整与优化,从而优化其动态特性.     

An adaptive observer for joint estimation of states and parameters in both state and output equations

An adaptive observer is a recursive algorithm for joint state–parameter estimation of parameterized state‐space systems. Previous works on globally convergent adaptive observers consider unknown parameters either in state equations or in output equations, but not in both of them. In this paper, a new adaptive observer is designed for linear time‐varying systems with unknown parameters in both state and output equations. Its global convergence for simultaneous estimation of states and parameters is formally established under appropriate assumptions. A numerical example is presented to illustrate the performance of this adaptive observer. Copyright © 2011 John Wiley & Sons, Ltd.     

SLUG试验及其水文地质参数的研究

Slug试验是通过记录地下水位瞬间变化来评价水文地质参数的现场测试方法。本文是在国外该试验发展的基础上,通过利用高精度测试,尝试对中、高渗透率含水层各参数进行测定。基于现场测试和已有的抽水资料,初步探讨了各种理论模型的不同,并以经典Cooper模型分析计算长春某场地的水文地质参数;通过对比抽水试验,验证了该试验的准确性...     

Assisted history matching in the presence of frequent well intervention using generalize travel time inversion

In this paper we propose an efficient and novel technique that handles production discontinuities through a resampling of the production data, eliminating high frequency production details in a transformed domain. The technique also reduces non-monotonic behavior and results in a response more suitable for the GTTI based misfit calculations. Our proposed approach has been applied to an offshore turbidite reservoir with extensive well intervention resulting in highly detailed production responses. The static model contains more than three-hundred-thousand cells, complex sand depositional distribution combined with fault structures, four pairs of injector-producers, deviated producing wells and more than 8 years of production history. Previous history matching attempts using traditional approaches had difficulties matching production response at the individual well level. With our proposed modifications to the GTTI approach, a significant improvement was obtained on the well level match quality. Most importantly, by visualizing the streamlines and the dynamic adjustment of flow paths during history matching, we could easily identify the areas of inconsistency between the geologic model and the production data. The calibrated geologic model and streamline trajectories provided important insight about communication within sand channels, differences in flow paths and barriers that have not been included in the previous geologic and seismic interpretation.     

Characterization of gelatinized corn starch suspensions and resulting drop size distributions after effervescent atomization

Effervescent atomization is a promising method for economical atomization of high viscous liquids like gelatinized corn starch suspensions. The gelatinization of starch has strong influence on the viscosity of starch suspensions. It was characterized adapting a method for determination of the gelatinization degree. Rheological properties of gelatinized corn starch suspensions with concentrations ranging from 5 to 7 wt.-% were investigated. Effervescent atomization proved to be largely invariant to variations of liquid viscosity in this range. Relative gas injection pressure proved to be of highest influence on the resulting drop size distribution when varying only atomizer geometry. Applying Abel inversion to drop size measurement results depicted the opposite trend of drop sizes depending on radial position in the spray than observed by other researchers working with aqueous glass bead suspensions. Compared to conventional external mixing pneumatic atomization a reduction of atomization gas quantity of up to four times could be achieved.