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Diffusion tensor imaging-derived measures of fractional anisotropy across the pyramidal tract are influenced by the cerebral hemisphere but not by gender in young healthy volunteers： a split-plot factorial analysis of variance

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Chinese Medical Journal 2012年第12期125卷 2180-2187页

作者： Ernesto Roldan-Valadez Edgar Rios-Piedra Rafael Favila Sarael Alcauter Camilo Rios Magnetic Resonance Unit Medica Sur Clinical FoundationMexico CityMexico Tecnologico de Monterrey Health Sciences DivisionMexico City CampusMexico GE Healthcare Mexico CityMexico Imagenes Cerebrales Instituto Nacional de Psiquiatria Ramon dela Fuente Ciudad de MexicoMexico Department of Neurochemistry National Institute of Neurologyand NeurosurgeryMexico CityMexico

Background Diffusion tensor imaging （DTI） permits quantitative examination within the pyramidal tract （PT） by measuring fractional anisotropy （FA）. To the best of our knowledge, the inter-variability measures of FA along the PT remain unexplained. A clear understanding of these reference values would help radiologists and neuroscientists to understand normality as well as to detect early pathophysiologic changes of brain diseases. The aim of our study was to calculate the variability of the FA at eleven anatomical landmarks along the PT and the influences of gender and cerebral hemisphere in these measurements in a sample of young, healthy volunteers. Methods A retrospective, cross-sectional study was performed in twenty-three right-handed healthy volunteers who underwent magnetic resonance evaluation of the brain. Mean FA values from eleven anatomical landmarks across the PT （at centrum semiovale, corona radiata, posterior limb of internal capsule （PLIC）, mesencephalon, pons, and medulla oblongata） were evaluated using split-plot factorial analysis of variance （ANOVA）. Results We found a significant interaction effect between anatomical landmark and cerebral hemisphere （F （10, 32）=4.516, P=0.001; Wilks＇ Lambda 0.415, with a large effect size （partial η2=0.585））. The influence of gender and age was non-significant. On average, the midbrain and PLIC FA values were higher than pons and medulla oblongata values; centrum semiovale measurements were higher than those of the corona radiata but lower than PLIC. Conclusions There is a normal variability of FA measurements along PT in healthy individuals, which is influenced by regions of interest location （anatomical landmarks） and cerebral hemisphere. FA measurements should be reported for comparing same-side and same-landmark PT to help avoid comparisons with the contralateral PT; ideally, normative values should exist for a clinically significant age group. A standardized package of selected DTI processing tools would al

关键词： anisotropy diffusion tensor imaging magnetic resonance imaging multivariate analysis analysis of variance

ONE-WAY MULTIVARIATE REPEATED MEASUREMENTS analysis of variance MODEL

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Applied Mathematics(A Journal of Chinese Universities) 2004年第4期19卷 435-448页

作者： Abdul-Hussein Saber AL-MOUEL Dept. of Statist. East China Normal Univ. Shanghai 200062China

The one-way multivariate repeated measurements analysis of variance (1-way MRM ANOVA) model for complete data and the sphericity test are studied.

关键词： one-way multivariate repeated measurements analysis of variance likelihood ratio criterion sphericity test asymptotic expansion.

Mold Wear During Die Forging Based on variance analysis and Prediction of Die Life

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Transactions of Nanjing University of Aeronautics and Astronautics 2020年第6期37卷 872-883页

作者： CAI Ligang LIU Haidong PAN Junjie CHENG Qiang CHU Hongyan Beijing Key Laboratory of Advanced Manufacturing Technology Beijing University of TechnologyBeijing 100124P.R.China Guizhou Anda Aviation Forging Co Ltd Anshun 561005P.R.China

A process parameter optimization method for mold wear during die forging process is proposed and a mold life prediction method based on polynomial fitting is presented,by combining the variance analysis method in the orthogonal test with the finite element simulation test in the forging *** process parameters with the greatest influence on the mold wear during the die forging process and the optimal solution of the process parameters to minimize the wear depth of the mold are *** hot die forging process is taken as an example,and a mold wear correction model for hot forging processes is derived based on the Archard wear *** element simulation analysis of die wear process in hot die forging based on deform software is performed to study the relationship between the wear depth of the mold working surface and the die forging process parameters during hot forging *** optimized process parameters suitable for hot forging are derived by orthogonal experimental design and analysis of *** average wear amount of the mold during the die forging process is derived by calculating the wear depth of a plurality of key nodes on the mold *** life for the entire production process is predicted based on average mold wear depth and polynomial fitting.

关键词： die forging process Deform analysis of variance mold wear die life prediction

Modeling and analysis of pelletization process based on a multi-hole pelletizing device

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International Journal of Agricultural and Biological Engineering 2019年第1期12卷 17-23页

作者： Qinghai Jiang Kai Wu Yu Sun School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China

A multi-hole pelletizing device(MPD)was proposed to simulate the granular extrusion process of animal feed due to its cheap,fast,and controllable *** compression mechanism was analyzed and discussed according to the compression force-time *** study applied response surface methodology(RSM)with a central composite design(CCD)to develop predictive models for the compression force Fout and the pellet properties which includes pellet densityρp,pellet moisture content Mcp,and pellet tensile strength Dp based on the *** effects of feedstock moisture content Mcf(10%-18%w.b.),feedstock particle size Sf(8 meshes-24 meshes),die temperature Td(70°C-110°C)and compression speed Vc(5 mm/min to 25 mm/min)were *** surface models developed for the compression force and pellet properties have adequately described the pelleting process(R^(2)>0.95).The results showed the significant effects of all factors and most of the squared and interaction terms on the compression force and pellet physical *** can be concluded from the present study that moisture content and die temperature,followed by compression speed and feedstock particle size are the interacting process factors influencing compression force and pellet properties.

关键词： animal feed pelletization modeling compression force response surface methodology analysis of variance

AN　analysis　OF　AMULTIVARIATE　TWO－WAY　MODEL　WITH　INTERACTION　AND　NO　REPLICATION

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Acta Mathematicae Applicatae Sinica 1994年第4期10卷 387-400页

作者：郭大伟 Anhui Normal University

In this paper, we consider the problem of testing the hypothesis of no interaction in the multivariate two-way classification model with one observation per cell. If the error covariance matrix is unknown, we suggest pseudo-maximum likelihood estimation (PMLE) of the parameters and give the invariant test for the hypothesis of no interaction. Further, we develop also some tests for the case of an unknown diagonal positive definite error covariance matrix.

关键词： analysis of variance interaction pseudo-maximum likelihood estimate maximal invariant, invariant test

Establishing empirical relationships to predict grain size and tensile strength of friction stir welded AA 6061-T6 aluminium alloy joints

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Transactions of Nonferrous Metals Society of China 2010年第10期20卷 1863-1872页

作者： S.RAJAKUMAR C.MURALIDHA RAN V.BALASUBRAMANIAN Department of Manufacturing Engineering Annamalai University

AA 6061-T6 aluminium alloy(Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high specific strength and good corrosion *** with the fusion welding processes that are routinely used for joining structural aluminium alloys,friction stir welding(FSW) process is an emerging solid state joining process in which the material welded does not melt and *** strength is influenced by the grain size and tensile strength of the weld nugget ***,an attempt was made to develop empirical relationships to predict grain size and tensile strength of friction stir welded AA 6061-T6 aluminium alloy *** empirical relationships are developed by response surface methodology(RSM) incorporating FSW tool and process parameters.A linear regression relationship was also established between grain size and tensile strength of the weld nugget of FSW joints.

关键词： AA 6061-T6 alloy friction stir welding analysis of variance regression analysis grain size tensile strength

Optimization of tribological parameters over WC-12%Co laser alloyedpearlitic ductile iron using Taguchi based Grey relational analysis

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Journal of Central South University 2020年第3期27卷 736-751页

作者： N.JEYAPRAKASH YANG Che-hua TSENG Sheng-po Centre of Mass Customization Additive Manufacture National Taipei University of TechnologyTaiwanChina Institute of Manufacturing Technology National Taipei University of TechnologyTaiwanChina

Pearlitic ductile irons(PDIs)are used in transportation and nuclear energy *** heavy loading situation,the service life of PDI is affected by numerous tribo *** this study,surface of the PDI is alloyed with WC-12%Co powder using a high power fibre *** wear properties of the base material and laser alloying samples were investigated by tribometer with various parameters,i.e.,temperature,load and sliding *** on experimental test,the load has maximum percentage of contribution and followed by sliding speed and working *** optimized tribological parameters by Grey relational analysis(GRA)were established and those values are closely matched with predicted ***,base material and laser alloying surfaces were examined through Vickers hardness machine,scanning electron microscopy(SEM)and roughness *** laser altered specimen shows no defects and improves the wear properties than *** identified optimal tribological parameters are load of 30 N,speed of 0.5 m/s and working temperature of 300℃,and load of 30 N,speed of 0.5 m/s and working temperature of 200℃ for base metal and laser alloying samples,respectively.

关键词： WC-12%Co laser alloying microstructure wear resistance Grey technique analysis of variance optimization roughness

A novel optimal design for an application-oriented synthetic jet actuator

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Chinese Journal of Aeronautics 2014年第3期27卷 514-520页

作者： Deng Xiong Xia Zhixun Luo Zhenbing Wang Lin Science and Technology on Scramjet Laboratory National University of Defense Technology

The evaluation indicator for the performance of a synthetic jet actuator （SJA） is well-defined because of its various applications, which require optimal design to improve its performance and extend its field of application. This paper presents a novel approach to the optimal design of an SJA applied to enhance fuel/air mixture. It optimizes the combination of an actuator＇s geometric parameters by selecting the strength of vortex pairs as the evaluation indicator, coupled with orthogonal experiments and analysis of variance （AOV）. The results indicate that slot width is the most notable factor influencing the strength of vortex pairs, followed by cavity height and slot depth. The optimal value of the strength of vortex pairs increases by 32.5%over the experimental data of the base case, and more than 8.4%compared with the simulation results of the orthogonal experiments. It is concluded that the optimal method can effectively improve the performance of an SJA applied in mixing enhancement, reducing the test numbers and the associated design cycle and cost.

关键词： analysis of variance Evaluation indicator Orthogonal experiment Strength of vortex pairs Synthetic jet

Wear Studies on Metal Matrix Composites: a Taguchi Approach

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Journal of Materials Science & Technology 2005年第6期21卷 845-850页

作者： S.Basavarajappa G.Chandramohan Department of Mechanical Engineering PSG College of Technology 641 004 Coimbatore India

An attempt has been made to study the influence of wear parameters like applied load, sliding speed, sliding distance and percentage of reinforcement on the dry sliding wear of the metal matrix composites. A plan of experiments, based on techniques of Taguchi, was performed to acquire data in controlled way. An orthogonal array and the analysis of variance were employed to investigate the influence of process parameters on the wear of composites. The objective is to establish a correlation between dry sliding wear of composites and wear parameters. These correlations were obtained by multiple regressions. Finally, confirmation tests were conducted to verify the experimental results foreseen from the mentioned correlations.

关键词： Metal matrix composites Wear Orthogonal array analysis of variance Taguchi method