TG-DSC技术在水泥研究中的应用

采用热重分析(TG)和差示扫描量热分析(DSC)研究了水泥生料转变成的热效应特征和水泥水化产物含量变化规律,重点研究了Al坩埚封装方式(高压密闭、低压密闭和传统加盖扎孔)对TG-DSC方法分析水泥中石膏结晶水含量的影响。发现Al坩埚密闭时石膏脱水的两个热效应峰完全分开,可大大提高热焓法定量分析二水石膏中不同性质结晶水含量的精度。     

双锥粉料罐系统静力学有限元分析

建立了双雏粉料罐系统的ANSYS模型，计算出了粉料罐系统静力状况下以及风载荷作用下的应力数值，通过计算得出，双雏粉料罐系统部分设计强度不足，此信论为该产品前期设计提供了重要参考。     

热导式等温量热仪在水泥水化研究中的应用

介绍了等温量热法测量的原理、典型的仪器以及在水泥水化研究中应用所具有的特点.通过它可以获得完整的水泥水化过程产热曲线;可以研究水泥在不同条件下的水化反应规律.     

喷墨式水泥3D打印喷头泥浆流动规律分析

基于熔融沉积成型3D打印工艺,介绍了喷头直接挤出水泥浆的喷墨式水泥3D打印工艺,并通过进料口压力、喷口直径、螺杆转速和螺杆几何尺寸对喷头出料率影响的实验,研究了喷头内水泥浆的流动规律,指出了影响喷头出料的关键因素.     

Tridimensional quantitative porosity characterization of three set calcium silicate‐based repair cements for endodontic use

The aim of the this study was to quantitatively evaluate in three‐dimensional (3D), the porosity degree of three improved silicate‐based endodontic repair cements (iRoot BP Plus^®, Biodentine^®, and Ceramicrete) compared to a gold‐standard calcium silicate bioactive cement (Pro Root^® MTA). From each tested cement, four samples were prepared by a single operator following the manufacturer's instructions in terms of proportion, time, and mixing method, using cylindrical plastic split‐ring moulds. The moulds were lubricated and the mixed cements were inserted with the aid of a cement spatula. The samples were scanned using a compact micro‐CT device (Skyscan 1174, Bruker micro‐CT, Kontich, Belgium) and the projection images were reconstructed into cross‐sectional slices (NRecon v.1.6.9, Bruker micro‐CT). From the stack of images, 3D models were rendered and the porosity parameters of each tested material were obtained after threshold definition by comparison with standard porosity values of Biodentine^®. No statistically significant differences in the porosity parameters among the different materials were seen. Regarding total porosity, iRoot BP Plus^® showed a higher percentage of total porosity (9.58%), followed by Biodentine^® (7.09%), Pro Root^® MTA (6.63%), and Ceramicrete (5.91%). Regarding closed porosity, Biodentine^® presented a slight increase in these numbers compared to the other sealers. No significant difference in porosity between iRoot BP Plus^®, Biodentine^®, and Ceramicrete were seen. In addition, no significant difference in porosity between the new calcium silicate‐containing repair cements and the gold‐standard MTA were found. Microsc. Res. Tech., 76:1093–1098, 2013. © 2013 Wiley Periodicals, Inc.     

A comparison of single particle tracking and temporal image correlation spectroscopy for quantitative analysis of endosome motility

Single particle tracking (SPT) is becoming a standard method to extract transport parameters from time‐lapse image sequences of fluorescent vesicles in living cells. Another method to obtain these data is temporal image correlation spectroscopy (TICS), but this method is less often used for measurement of intracellular vesicle transport. Here, we present an extensive comparison of SPT and TICS. First we examine the effect of photobleaching, shading and noise on SPT and TICS analysis using simulated image sequences. To this end, we developed a simple photophysical model, which relates spatially varying illumination intensity to the bleaching propensity and fluorescence intensity of the moving particles. We found that neither SPT nor TICS are affected by photobleaching per se, but the transport parameters obtained by both methods are sensitive to the signal‐to‐noise ratio. In addition, the number of obtained trajectories in SPT is affected by noise. Diffusion constants determined by TICS are significantly overestimated when large immobile fluorescent structures are present in the image sequences, while the opposite is true for SPT. To improve the performance of both techniques, we compare three different methods for image denoising. Appropriate denoising significantly reduced the effect of noise and of immobile structures on both methods. Shape fluctuations of simulated particles had a more pronounced effect on TICS than on SPT analysis. In denoised images of fluorescent beads or cytosolic vesicles containing fluorescent protein NPC2 in human skin fibroblast cells, the transport parameters acquired by SPT and TICS were comparable emphasizing the value of both analysis methods.     

水泥设备主动维修策略的探讨

在概述水泥行业设备维修现状的基础上,探讨了主动维修策略的内涵,构建了主动维修策略维修方式的决策模型,最后对主动维修策略应用于水泥设备做了简要说明.     

Development of advanced quantitative analysis methods for wear particle characterization and classification to aid tribological system diagnosis

Classification of wear particles is performed in two steps, i.e. first a particle to be classified is characterized by surface feature parameters such as roughness, directionality, homogeneity, periodicity, etc. and then, the particle is assigned to a specific class using these parameters. However, a significant limitation of this approach is that surface parameters are often not unique to a specific surface topography and their values may change significantly with scale, orientation angle and position at which the particle data was acquired. Various attempts were made to overcome this limitation by selecting a core set of parameters which ensures that wear particles are accurately classified. However, the parameter selection is usually cumbersome and requires lengthy computation. Furthermore, there is no guarantee that parameters selected are sensitive enough to separate particles belonging to different classes. Thus, a new classification technique based entirely on dissimilarity measures (e.g. Euclidean, Baddeley's distances), calculated between surface images of an unclassified particle and classified particles, was developed. The classification process is based on assigning a particle to a class of particles with the smallest dissimilarity measure. This idea arises naturally from the two facts: (i) compactness, similar objects are in close proximity to each other in their representation space, while different objects are far apart, and (ii) true representation, if objects are close to each other in their representation space they belong to the same class. In this paper, an overview of recent advances and developments in the area of particle classification based on dissimilarity measures is presented with a particular emphasis on constructing a simple and accurate classifier.     

链板式配料秤在水泥行业中的应用

本文主要介绍了链板式配料秤近几年在水泥厂的应用,分析了配料秤的工作原理和运行特点,比较了模拟传感器和数字传感器的各自特点,并对影响配料秤稳定性和精度的因素进行分析。     

Single particle raster image analysis of diffusion for particle mixtures

Recently we complemented the raster image correlation spectroscopy (RICS) method of analysing raster images via estimation of the image correlation function with the method single particle raster image analysis (SPRIA). In SPRIA, individual particles are identified and the diffusion coefficient of each particle is estimated by a maximum likelihood method. In this paper, we extend the SPRIA method to analyse mixtures of particles with a finite set of diffusion coefficients in a homogeneous medium. In examples with simulated and experimental data with two and three different diffusion coefficients, we show that SPRIA gives accurate estimates of the diffusion coefficients and their proportions. A simple technique for finding the number of different diffusion coefficients is also suggested. Further, we study the use of RICS for mixtures with two different diffusion coefficents and investigate, by plotting level curves of the correlation function, how large the quotient between diffusion coefficients needs to be in order to allow discrimination between models with one and two diffusion coefficients. We also describe a minor correction (compared to published papers) of the RICS autocorrelation function.     

Wear particle analysis—utilization of quantitative computer image analysis: A review

This paper provides a general overview of developments and progress in quantitative computer image analysis as applied to wear particle identification/classification technology, over the last two decades. Since many technical disciplines are involved in this ‘infant-stage’ technical area, an attempt is made to put into perspective mechanical failure prediction/diagnosis and prevention through quantitative wear particle morphological analysis. The problems experienced with applying conventional wear particle analysis methods in machinery condition monitoring, notably the employment of wear debris morphological diagnostic systems, revealed that it is not prudent to rely solely on human interpretation in the analysis of ‘filtergram’ slides. This has highlighted the need for improving the provision of ‘intelligent’ objective methods for performing this type of analysis. In this paper, some of the developments reported in the literature relating to progress made with wear particle image analysis are reported and examined as a basis for establishing improved methods of diagnostic analysis.     

Quantitative microstructure analysis of polymer-modified mortars

Digital light, fluorescence and electron microscopy in combination with wavelength‐dispersive spectroscopy were used to visualize individual polymers, air voids, cement phases and filler minerals in a polymer‐modified cementitious tile adhesive. In order to investigate the evolution and processes involved in formation of the mortar microstructure, quantifications of the phase distribution in the mortar were performed including phase‐specific imaging and digital image analysis. The required sample preparation techniques and imaging related topics are discussed. As a form of case study, the different techniques were applied to obtain a quantitative characterization of a specific mortar mixture. The results indicate that the mortar fractionates during different stages ranging from the early fresh mortar until the final hardened mortar stage. This induces process‐dependent enrichments of the phases at specific locations in the mortar. The approach presented provides important information for a comprehensive understanding of the functionality of polymer‐modified mortars.     

Inter‐ and intragranular delta phase quantitative characterization in Inconel 718 by means of image analysis

This paper describes an image processing method for discriminating the inter‐ and intragranular delta phase precipitates in Inconel 718 (IN 718). The successive practical operations and the motivations of their choices are presented in detail. The method was applied to IN 718 specimens heat treated with different parameters to produce microstructures containing various amounts of both types of precipitates. They were characterized by electron microscopy in backscattered electron imaging. The main difficulty arose from the fact that the brightness distributions of inter‐ and intragranular precipitates partially overlap. Additional information on their morphology and their spatial distribution had to be exploited in order to differentiate them. The shape and the orientation of the precipitates were evaluated using the structure tensor, an operator that quantifies the directionality of the intensity distribution in an image. The distance between parallel precipitates was also used as an additional property to identify clusters of intragranular precipitates.     

超细颗粒悬浊液超声衰减谱与声速谱测量研究

将短时傅里叶变换应用于超细颗粒两相介质中超声脉冲信号处理和时频谱联合分析,采用变声程方式,提出了一种对超细颗粒两相介质声衰减谱与声速谱同时测量的方法,并对平均粒径281nm的ZnO-H2O悬浊液超声衰减谱与声速谱进行实验研究。     

Focussed ion beam nanotomography reveals the 3D morphology of different solid phases in hardened cement pastes

Due to the development of integrated low-keV back-scattered electron detectors, it has become possible in focussed ion beam nanotomography to segment not only solid matter and porosity of hardened cement paste, but also to distinguish different phases within the solid matter. This paper illustrates a method that combines two different approaches for improving the contrast between different phases in the solid matrix of a cement paste. The first approach is based on the application of a specially developed 3D diffusion filter. The second approach is based on a modified data-acquisition procedure during focussed ion beam nanotomography. A pair of electron images is acquired for each slice in the focussed ion beam nanotomography dataset. The first image is captured immediately after ion beam milling; the second image is taken after a prolonged exposure to electron beam scanning. The acquisition of complementary focussed ion beam nanotomography datasets and processing the images with a 3D anisotropic diffusion filter allows distinguishing different phases within the hydration products.     

关于散装水泥料罐秤计量检定方法的探讨

水泥生产企业用于对散装水泥专用运输船舶进行计量的散装水泥料罐秤,由于罐体直径和高度均达数十米、最大储存一般在数百吨,无法放置大质量砝码,因此,计量检定十分困难;加之有些水泥生产企业,计量法律、法规意识薄弱,计量检定登记受检率相当低,其计量性能无法确保准确,水泥生产企业和消费企业由此引起的经济纠纷时有发生。为改变这一状况,本人所在的计量技术机构对此进行了探索,运用替代法,进行散装水泥料罐秤的静态计量检定,取得了一定的经验,在此抛砖引玉,旨在对计量检定同行和有关企业有所启迪。     

水泥混凝土路面刻槽磨损程度三维检测方法

为了实现水泥混凝土路面刻槽磨损程度的自动检测,基于激光三角法实现了路面三维信息的采集与处理。结合刻槽三维数据的特点,通过数据插值技术和曲面拟合获取了刻槽区域的并行曲面,并建立了刻槽的三维空间模型,采用双重均值的方法实现了刻槽区域平均构造深度的计算。设计试验对三维检测方法和铺砂法进行了对比分析,试验结果表明,本文提出的三维检测方法比铺砂法有更好的稳定性;两种方法的检测结果绝对误差大部分集中在0.1 mm以内,且相关性高,从而证明了三维检测方法有一定的准确性和可靠性,可用于刻槽区域磨损程度的自动检测。     

Issues in confocal microscopy for quantitative FRET analysis

Previously, we have carried out extensive quantitative analysis of F?rster (or fluorescence) resonance energy transfer (FRET) data to show that polymeric IgA receptors and their ligands cluster in endocytic membranes in the process of sorting and trafficking in polarized cells. Here, we use a similar technique to assay the organization and distribution of another membrane-bound receptor: transferrin receptor (TFR) and its ligand, holo-transferrin (Tfn), while explaining the step-by-step measures to be taken for successful quantitative analysis of the FRET data. In particular, methodological issues in FRET quantitative imaging, such as spectral bleed-through and background correction, optimal selection of regions of interest, how to deal with outliers and pooling data and statistical analysis of FRET data, are addressed. Our results indicating a clustered organization of TFR-Tfn complexes fit the well-known homodimeric structure of TFR. These quantitative approaches can be adapted for other biological applications of FRET.     

Added advantages in using a fiber Bragg grating sensor in the determination of early age setting time for cement pastes

A fiber Bragg grating (FBG) sensor was used to monitor the early age curing temperatures of cement paste. Additional advantages in using the sensor were highlighted. The FBG was inscribed by a Continuous Wave 244 nm argon ion laser in the photosensitivity fiber. The fabricated FBG was calibrated from room temperature to 105 °C. In this temperature range, the FBG was found to be good in terms of both the sensitivity and linearity which were around 9 pm/°C and 99.9%, respectively. A host specimen with ratio of Portland cement, sand and water of 800, 500, and 275 ml by volume was used in the experiment. Results showed that the FBG could determine the initial and the final early age setting times. The initial early age setting time for the cement paste was about 5 h and the final early age setting time was about 14 h after casting.