Nanoscale Reciprocating Sliding Contacts of Textured Surfaces:Influence of Structure Parameters and Indentation Depth

Textured surfaces are widely used in engineering components as they can improve tribological properties of sliding contacts, while the detailed behaviors of nanoscale reciprocating sliding contacts of textured surfaces are still lack of study. By using multiscale method, two dimensional nanoscale reciprocating sliding contacts of textured surfaces are investigated. The influence of indentation depth, texture shape, texture spacing, and tip radius on the average friction forces and the running-in stages is studied. The results show that the lowest indentation depth can make all the four textured surfaces reach steady state. Surfaces with right-angled trapezoid textures on the right side are better for reducing the running-in stage, and surfaces with right-angled trapezoid textures on the left side are better to reduce wear. Compared with other textured surfaces, the total average friction forces can be reduced by 82.94%–91.49% for the case of the contact between the tip with radius R = 60rand the isosceles trapezoid textured surface. Besides,the total average friction forces increase with the tip radii due to that bigger tip will induce higher contact areas. This research proposes a detailed study on nanoscale reciprocating sliding contacts of textured surfaces, to contribute to design textured surfaces, reduce friction and wear.

Impact of Zener-Hollomon parameter on substructure and texture evolution during thermomechanical treatment of iron-containing wrought aluminium alloys

The objective of the investigation is to evaluate the influence of the Zener-Hollomon parameter on substructure and texture evolution in iron-containing wrought aluminium alloys (type AA8011). Methods applied are X-ray texture analysis, electron backscatter diffraction (EBSD) and optical microscopy. The results show a serious impact of the Zener-Hollomon parameter on cube texture evolution during the thermomechanical treatment in iron-containing aluminium alloys. An increase in the Zener-Hollomon parameter reduces the survivability of cube texture during hot deformation and reinforces particle-stimulated nucleation (PSN) during the annealing process. However, thermomechanical treatment at low temperatures leads to active precipitation and as a result fine-dispersed participles tend to block all nuclei except for those producing large cube-oriented grains. It is concluded that in iron-containing wrought aluminium alloys, the general correlation between the Zener-Hollomon parameter and subgrain size is similar to that observed in 3xxx series alloys and can be described by the specific set of equations derived.

Correlation of image textures of a polarization feature parameter and the microstructures of liver fibrosis tissues

Mueller matrix imaging is emerging for the quantitative characterization of pathological microstructures and is especially sensitive to fibrous structures.Liver fibrosis is a characteristic of many types of chronic liver diseases.The clinical diagnosis of liver fibrosis requires time-consuming multiple staining processes that specifically target on fibrous structures.The staining proficiency of technicians and the subjective visualization of pathologists may bring inconsistency to clinical diagnosis.Mueller matrix imaging can reduce the multiple staining processes and provide quantitative diagnostic indicators to characterize liver fibrosis tissues.In this study,a fibersensitive polarization feature parameter(PFP)was derived through the forward sequential feature selection(SFS)and linear discriminant analysis(LDA)to target on the identification of fibrous structures.Then,the Pearson correlation coeffcients and the statistical T-tests between the fiber-sensitive PFP image textures and the liver fibrosis tissues were calculated.The results show the gray level run length matrix(GLRLM)-based run entropy that measures the heterogeneity of the PFP image was most correlated to the changes of liver fibrosis tissues at four stages with a Pearson correlation of 0.6919.The results also indicate the highest Pearson correlation of 0.9996 was achieved through the linear regression predictions of the combination of the PFP image textures.This study demonstrates the potential of deriving a fiber-sensitive PFP to reduce the multiple staining process and provide textures-based quantitative diagnostic indicators for the staging of liver fibrosis.

Classification of wood surface texture based on Gauss-MRF Model

The basal theory of Gauss-MRF is expounded and 2-5 order Gauss MRF models are established. Parameters of the 2-5 order Gauss-MRF models for 300 wood samples＇ surface texture are also estimated by using LMS. The data analysis shows that： 1） different rexture parameters have a clear scattered distribution, 2） the main direction of texture is the direction represented by the maximum parameter of Gauss-MRF parameters, and 3） for those samples having the same main direction, the finer the texture is, the greater the corresponding parameter is, and the smaller the other parameters are; and the higher the order of Gauss-MRF is, the more clearly the texture is described. On the condition of the second order Gauss MRF model, parameter B1, B2 of tangential texture are smaller than that of radial texture, while B3 and B4 of tangential texture are greater than that of radial texture. According to the value of separated criterion, the parameter of the fifth order Gauss-MRF is used as feature vector for Hamming neural network classification. As a result, the ratio of correctness reaches 88%.

Gabor Filter Optimization Design for Iris Texture Analysis

This paper deals with an optimization design method for the Gabor filters based on the analysis of an iris texture model. By means of analyzing the properties of an iris texture image, the energy distribution regularity of the iris texture image measured by the average power spectrum density is exploited, and the theoretical ranges of the efficient valued frequency and orientation parameters can also be deduced. The analysis shows that the energy distribution of the iris texture is generally centralized around lower frequencies in the spatial frequency domain. Accordingly, an iterative algorithm is designed to optimize the Gabor parameter field. The experimental results indicate the validity of the theory and efficiency of the algorithm.

Optimization of Texture Determination of ‘Yali' by Texture Analyzer

[Objectives] This study was carried out to determine texture parameters for texture profile analysis （TPA）, and optimize the texture determination of ‘Yali’ by texture analyzer.[Methods] The traditional varieties of ‘Yali’ were taken as the materials, and texture parameters were determined at different compression rates and deformations at target.[Results] In the process of the TPA, the deformation at target had an extremely significant influence on 8 TPA texture parameters, namely, the hardness, cohesiveness, springiness, adhesiveness, gumminess, resilience, fracturability, and chewiness （ P ≤0.01）, while the compression rate had significant influence on the hardness and gumminess （ P ≤0.05）, had an extremely significant influence on fracturability （ P ≤0.01）, and had no significant influence on other 5 TPA parameters.[Conclusions] Taking the compression rate of 1 mm/s and 20% deformation at target as the experimental conditions for TPA could avoid the impact load of high speed on the tissue and objectively reflect the textural characteristics of ‘Yali’ pulp tissue.

Morphological parameters of both surfaces of coupled joint

Twenty one joints were made with Brazilian tests and each surface was scanned by the Talysurf CLI 2000. Morphological characteristics of joint surface were quantified by statistical and textural parameters. By the contrast of these parameters between both sides of each coupled joint, the following conclusions are drawn. The upper and lower surfaces of coupled joints have approximately equal values of Sp（maximum height of joint surface）, Sa（arithmetic mean height of joint surface） and Sq（root mean square height of joint surface）, but the Ssk（skewness of the height distribution of joint surface） values of the two surfaces of a coupled joint are different, one is positive while the other is negative. The Saj（auto-correlation length） parameter values of both surfaces of each coupled joint are quite close, and the S^（texture aspect ratio） values have the same situation to the Sal parameter, but the same parameters of different surfaces have big differences which illustrates its own characteristics of each joint. The two surfaces of each coupled joint have similar values of θp （mean profile angle） which can be used to deduce the value of θp each other.

The effects of grain texture and phenotypic traits on the thin-layer drying rate in maize(Zea mays L.) inbred lines

To explore the relation of maize grain texture and phenotypic traits with grain thin-layer drying rate,we observed the ultra-structure of maize grain,and tested three traits about the maize grain texture and four phenotypic traits.The vitreous part percentage was different（P〈0.05） among different maize inbred lines.There was a significant relationship between the drying rate with grain texture and phenotypic traits.Main factors that influenced the drying rate were different during different drying stages.New results observed that empirical constants（k and N） in drying equation were different for seed of the 30 inbred lines of maize.The k of simplified diffusion equation and N of page equation were significantly influenced by both grain texture and phenotypic traits.These results could be used as guideline parameters for drying maize seeds having different grain characteristics during different drying stages.

THE DECISION OF THE OPTIMAL PARAMETERS IN MARKOV RANDOM FIELDS OF IMAGES BY GENETIC ALGORITHM

This paper introduces the principle of genetic algorithm and the basic method of solving Markov random field parameters.Focusing on the shortcomings in present methods,a new method based on genetic algorithms is proposed to solve the parameters in the Markov random field.The detailed procedure is discussed.On the basis of the parameters solved by genetic algorithms,some experiments on classification of aerial images are given.Experimental results show that the proposed method is effective and the classification results are satisfactory.

A New Texture Analysis Approach

A new texture analysis approach by using Gibbs random field model is discussed. A parameter vector is defined in order to compute potentials of textures. It is found that texture features can be provided by its corresponding parameter vector, and the vector can be estimated in terms of maximum potential. Conclusions can be inferred that this new method based on the maximum potential is valid.

Effects of melt spinning process parameters and wheel surface quality on production of 6060 aluminum alloy powders and ribbons

The aim of this study is to investigate the surface quality of the melt spinning wheel, which was changed from smooth type to textured structure, to atomize liquid metal to form powders. The effects of melt spinning process parameters like wheel speed, gas ejection pressure, molten metal temperature, nozzle–wheel gap and wheel surface quality on the morphological and microstructural features of 6060 aluminum alloy powders and ribbons were investigated. It was observed that ribbon type material was obtained with the smooth wheel and the powder was produced with textured type. The sizes of produced ribbons with smooth surface wheel varied in the range of 30-170 μm in thickness, 4-8 mm in width, and 0.5-1 m in length. The average powder size of the powders manufactured using the textured wheel was in the range of 161-274 μm, depending on the process parameters.Increasing the wheel speed, melt temperature and decreasing gas ejection pressure, nozzle-wheel gap resulted in the decrease of both ribbon thickness and powder size. The microstructures of the powders and ribbons were the equiaxed cellular type, and the average grain sizes diminished with decreasing the ribbon thickness and powder size. The maximum cooling rates were 2.00×10^5 and 1.26×10^4 K/s for the ribbon with thickness of 30 μm and for the powder with size of 87 μm, respectively.

Temperature Calculation of Pellet Rotary Kiln Based on Texture

In order to improve the quality of clinker produced by pellet rotary kiln, flame temperature that it is a very important factor of affecting on the quality of clinker is studied. The flame images collected from pellet rotary kiln are decomposed into three gray images by the method of RGB, so we can get more information of flame. Taking advantage of gray level co-occurrence matrix, the monitoring model for flame temperature based on image texture is established with RGB channels. In order to test the universality of the algorithm, candle flame temperature is detected by this method. The maximum error of the model is less than 3%.

Analysis of synergistic influence of multi-scale design parameters on nearly-zero energy office blocks performance based on architectural morphological classification and parametric modeling

Design parameters at different scales in the pre-design phase could significantly impact both building energy consumption and photovoltaic(PV)power generation potential.However,existing studies often overlook the synergistic effects of design parameters across multiple scales(block-building-facade scales)when evaluating these aspects.This paper aims to propose a workflow for the assessing building energy consumption and PV power generation potential of office blocks applicable in the pre-schematic design phase considering the synergistic influence of multi-scale design parameters,using building typology and parametric modelling approach.The study proposed a multi-scale design parameter classification system combined with parametric modelling.The study investigated 80 office blocks in Wuhan as the study case,which were classified into array type and enclosed type.Correlation analysis and multiple regression equations were used to quantify the single versus synergistic effects of different scale design parameters.Results suggest that focusing solely on a single scale during the pre-design stage is typically inadequate for understanding building energy potential.In contrast,multi-scale synergistic analysis boosts energy use intensity(EUI)by 7.56%and net energy use intensity(NEUI)by 33.96%.Under multi-scale synergistic conditions,the EUI of array type is more influenced by the building design parameters,while the NEUI is effected by the balance of multi-scales design parameters.While the EUI of enclosed types exhibit balanced effects across multi-scale design parameters,with NEUI results aligning closely with PV power generation potential.Multiple regression equations highlight building density and shape factor as key influencers for both array and enclosure layouts.This study offers designers a flexible and scalable workflow for evaluating building energy consumption and PV power generation potential in the pre-design phase.The findings can guide nearly-zero energy urban block planning to achieve a balance between energy supply and demand.

Quantitative Analysis of Relationships between Masseter Activity during Chewing and Textural Properties of Foods

The aim of this study was to quantify the relationships between four physiological parameters of masseter activity during chewing and properties related to the sizes and textures of the six representative test foods. The physiological parameters analyzed were the number of chewing cycles, chewing time, masseter amplitude, and cycle duration, which were obtained from masseter surface electromyography recorded in ten (seven male and three female) healthy, young participants. The six test foods differed in size dimensions (length, width, and height) and in textural properties (hardness, fracturability, and adhesiveness). The quantitative relationships were examined using linear regression. Nine statistically significant regression coefficients were found between the four physiological parameters and the textural properties, but not the height, of the test foods. From the regression coefficients, contributions of the food properties to the physiological parameters were estimated. Individual relationships between the physiological parameters and textural properties of the test foods are discussed in relation to their physiological implications.

织构化盘式摩擦副性能及优化设计研究

为探索提高盘式摩擦副抗摩擦磨损性能的有效途径,以斜盘柱塞泵配流副为研究对象,综合运用仿真分析及试验研究方法对比分析了面积织构率和截深形状相同条件下,椭圆开口和圆形开口离散凹坑微织构及沟槽形微织构配流副的摩擦因数随织构形貌、转速和压力的变化规律。研究结果表明:摩擦因数随转速的增大而显著降低,随压力的增大而降低,椭圆开口离散凹坑微织构为三种微织构中提高配流副性能最优者。对椭圆开口离散凹坑微织构进行多目标参数优化,得出的最优参数为:椭圆开口长轴半径为452μm、短半轴为187μm、径向中心距为0.7 mm。试验结果表明,优化后的织构在不同工况下较优化前摩擦因数和磨损量均有不同程度的降低。

凹坑织构对GCr15贫油滑动摩擦磨损性能影响

为研究在较大载荷和较高转速下,凹坑织构参数对GCr15贫油滑动摩擦磨损性能的影响,这里采用PL100-30W型激光打标机,在高碳铬轴承钢GCr15表面加工出规则排列的圆形凹坑阵列,然后利用MMW-1A型立式万能摩擦磨损试验机,对织构试样和光滑试样进行了贫油润滑条件下的摩擦磨损性能试验。最后,使用三维形貌仪对试样的磨损表面进行了表征。结果表明:凹坑织构表面对GCr15钢贫油润滑条件下的滑动摩擦磨损性能影响显著;存在最优的凹坑面积率和深径比,当其值为14.9%和1:12时,其摩擦系数和磨损量相比光滑试样分别降低了26%和64%;随着载荷的增大,织构试样与光滑试样的摩擦系数均呈上升趋势,但光滑试样的摩擦系数增长速率大于织构试样。

基于响应面法的Ni60/WC涂层表面织构皮秒分束工艺参数预测研究

目的实现六分束激光在Ni60/WC涂层表面烧蚀目标织构激光加工工艺参数的精确选择。方法基于CCD响应面法,设计在不同的激光工艺参数下对Ni60/WC涂层表面进行织构烧蚀试验,以激光频率、扫描次数、扫描速度为影响因素,以圆凹坑织构直径、深度及由其直径和深度综合加权所得的综合目标为响应目标,建立目标织构所需激光工艺参数的预测模型,以织构直径、深度及综合目标作为优化条件,对预测模型进行实验验证。结果扫描次数对织构直径的影响最显著,单个脉冲光斑上所聚集的能量大小是影响织构直径误差的关键因素。对织构深度影响最显著为扫描次数和频率,织构深度与扫描次数、频率呈正相关,不同因素间的交互作用是影响织构加工结果的关键。通过对预测模型所优选的参数进行实验验证发现,以织构直径和深度、综合目标建立的预测模型优选工艺参数所加工圆凹坑织构的质量评价指标与其预测指标的误差率分别为19.37%、3.57%。功率为6 W时,六分束激光加工最优工艺参数为速度5500 mm/s、频率400 kHz、扫描2次。结论通过综合目标建立的Ni60/WC涂层表面圆凹坑织构六分束激光加工参数优选预测模型精确程度较高,能够实现Ni60/WC涂层表面加工所需织构激光参数的准确预测,为涂层表面织构加工激光参数精确选择提供了理论依据。

微造型形状对滑动轴承摩擦特性的影响

利用激光微造型技术在滑动轴承轴颈表面加工出三角形、圆形和正方形微造型,分析不同形状微造型化滑动轴承的摩擦特性,并表征表面形貌,研究表征参数和摩擦特性的关系。结果表明:与未造型的滑动轴承相比,随着载荷增加,微造型后滑动轴承的摩擦系数逐渐减小,三角形微造型的滑动轴承摩擦系数最小,其次是圆形,最后是正方形。当表面偏态增加,摩擦系数升高,而表面峰态增加时,摩擦系数变化正好相反;当表面谷处和中心处平均空体体积增加时,摩擦系数先降低后升高,表面谷处及中心处平均空体体积分别为6.148×10^(-4)mm^(3)和5.418×10^(-3)mm^(3)时,摩擦系数最低;当表面峰和谷平均体积增加时,摩擦系数降低。在载荷3200 N及600 r/min时,微造型后滑动轴承的摩擦系数随着连通性系数的增加而降低。

织构几何参数对超疏水钛合金表面润湿性的影响

目的研究表面织构几何参数对超疏水钛合金表面润湿性的影响规律。方法利用纳秒激光在钛合金表面构筑不同织构间距、边长和形状的微织构,通过氟硅烷改善钛合金表面的润湿性;借助电子扫描显微镜(SEM)观察钛合金表面织构,利用接触角测量仪表征织构表面接触角;通过多元线性回归方法研究织构参数对钛合金表面润湿性的影响规律。结果氟硅烷改性试样表面静态接触角达到150°,满足超疏水要求,各织构表面滚动角基本稳定在4°~11°,满足疏水要求。当钛合金表面织构间距在0~0.6 mm变化时,织构相对试样表面的占比从80%至20%发生不等变化,随织构占比的减小,织构表面静态接触角明显下降,滚动角呈上升趋势。当织构边长在0~0.6 mm变化时,液滴在不同织构图案上的接触角变化并不一致,正方形钛合金表面接触角从164.6°增加到170°,而圆形、三角形钛合金表面接触角减小,分别从166.9°降低到162.1°、从169.6°降低到160.2°,滚动角呈先增后减的趋势。结论织构几何参数变化对试样表面润湿性有显著影响。织构间距不同会改变织构占比,织构图案几何特征的不同会影响表面润湿性,并且表面润湿性随织构面积的改变而显著变化。通过研究典型织构几何参数对表面润湿性的影响有利于进一步深入理解织构特征对表面润湿性的影响,为未来设计具有多元功能化的表面结构具有重要意义。

冠状动脉CT血管成像斑块纹理参数对初诊冠心病患者主要不良心血管事件的预测价值分析

目的:分析冠状动脉CT血管成像(CCTA)斑块纹理参数对初诊冠心病患者主要不良心血管事件(MACE)的预测价值。方法:选择2022年2月—2023年8月中国人民解放军联勤保障部队庐山康复疗养中心收治的116例初诊冠心病患者,以是否发生MACE为依据,将患者分为MACE发生组(n=37)和MACE非发生组(n=79)。依次为患者进行CCTA,比较两组的斑块纹理参数及既往用药史。进行多因素logistic回归分析,绘制通受试者操作特征(ROC)曲线,分析斑块纹理参数预测初诊冠心病患者MACE的准确性。结果:在本次116例初诊冠心病患者中共有37例患者发生MACE,其中有17例为血运重建的不稳定性心绞痛,占比为45.95%。两组对比度、峰度、偏度及既往用药史比较,差异均无统计学意义(P>0.05);MACE发生组熵、方差高于MACE非发生组,而角二阶矩、平均值低于MACE非发生组,差异均有统计学意义(P<0.05)。logistic回归分析显示,熵、方差为初诊冠心病患者发生MACE的危险因素,而角二阶矩为初诊冠心病患者发生MACE的保护因素(P<0.05)。ROC曲线分析显示,方差和熵预测初诊冠心病患者发生MACE的AUC分为0.882、0.789,角二阶矩预测初诊冠心病患者发生MACE的AUC为0.287。结论:CCTA斑块纹理参数在初诊冠心病患者MACE的预测中具有较高的诊断效能。