Pub Date : 2024-07-27DOI: 10.26896/1028-6861-2024-90-7-48-55
A. S. Segrenev, M. E. Prots
The reliability of the results of X-ray fluorescence analysis (XRF), which is widely used in determination of the elemental composition of various materials, largely depends on the quality of sample preparation. When producing pressed tablets for X-ray fluorescence analysis of trace elements, a binder is often used in a powder form, which requires significant time for thorough homogenization. We present the results of applicating a polyvinyl alcohol solution as a binder in the manufacture of pressed samples without using a substrate in determination of microelements by XRF. The parameters for obtaining a durable tablet with a homogeneous composition that matches the condition of minimum impact on the intensity of the analytical lines of the elements being determined are presented. It is shown that the optimal sample weight for the proposed method of producing pressed tablets is 7 g with the addition of polyvinyl alcohol in a ratio of 7:1, the optimal drying time for the tablet after pressing is 1 hour. The calculated variation coefficients of the analytical signal (<2%) indicate the homogeneity of the produced tablets. The maximum values of standard deviations of pressed tablets for the selected ranges of elements are much less than acceptable, which confirms the validity of the proposed method of sample preparation. It is also shown that during long-term storage and repeated measurements, pressed tablets with the polyvinyl alcohol solution retain their original structure and intensity of analytical lines of elements. The accuracy of measurements in the subsequent determination of rock-forming elements is consistent with their certified contents. The results obtained can be used to reduce the time spent on getting a representative pressed sample when using polyvinyl alcohol, determining elements without additional support (coating films), microelement and silicate analyzes from one sample.
X 射线荧光分析（XRF）广泛用于测定各种材料的元素组成，其结果的可靠性在很大程度上取决于样品制备的质量。在生产用于痕量元素 X 射线荧光分析的压制片剂时，通常使用粉末状的粘合剂，这需要大量时间进行彻底均质。我们介绍了将聚乙烯醇溶液作为粘合剂用于制造压制样品的结果，这种方法在利用 XRF 测定微量元素时无需使用基质。我们提出了获得具有均匀成分的耐用片剂的参数，这些成分应符合对所测定元素的分析线强度影响最小的条件。结果表明，采用所建议的方法生产压制片剂的最佳样品重量为 7 克，添加聚乙烯醇的比例为 7:1，压制后片剂的最佳干燥时间为 1 小时。计算得出的分析信号变异系数（小于 2%）表明所生产的片剂是均匀的。压制片剂在选定元素范围内的最大标准偏差值远远小于可接受值，这证实了所建议的样品制备方法的有效性。实验还表明，在长期储存和重复测量过程中，含有聚乙烯醇溶液的压片仍能保持其原有结构和元素分析线的强度。在随后的成岩元素测定中，测量结果的准确性与其认证含量一致。在使用聚乙烯醇、测定无附加支持物（涂膜）的元素、从一个样品进行微量元素和硅酸盐分析时，所获得的结果可用于减少获得具有代表性的压制样品所花费的时间。
{"title":"Evaluation of the use of polyvinyl alcohol in the manufacture of pressed samples for X-ray fluorescence analysis","authors":"A. S. Segrenev, M. E. Prots","doi":"10.26896/1028-6861-2024-90-7-48-55","DOIUrl":"https://doi.org/10.26896/1028-6861-2024-90-7-48-55","url":null,"abstract":"The reliability of the results of X-ray fluorescence analysis (XRF), which is widely used in determination of the elemental composition of various materials, largely depends on the quality of sample preparation. When producing pressed tablets for X-ray fluorescence analysis of trace elements, a binder is often used in a powder form, which requires significant time for thorough homogenization. We present the results of applicating a polyvinyl alcohol solution as a binder in the manufacture of pressed samples without using a substrate in determination of microelements by XRF. The parameters for obtaining a durable tablet with a homogeneous composition that matches the condition of minimum impact on the intensity of the analytical lines of the elements being determined are presented. It is shown that the optimal sample weight for the proposed method of producing pressed tablets is 7 g with the addition of polyvinyl alcohol in a ratio of 7:1, the optimal drying time for the tablet after pressing is 1 hour. The calculated variation coefficients of the analytical signal (<2%) indicate the homogeneity of the produced tablets. The maximum values of standard deviations of pressed tablets for the selected ranges of elements are much less than acceptable, which confirms the validity of the proposed method of sample preparation. It is also shown that during long-term storage and repeated measurements, pressed tablets with the polyvinyl alcohol solution retain their original structure and intensity of analytical lines of elements. The accuracy of measurements in the subsequent determination of rock-forming elements is consistent with their certified contents. The results obtained can be used to reduce the time spent on getting a representative pressed sample when using polyvinyl alcohol, determining elements without additional support (coating films), microelement and silicate analyzes from one sample.","PeriodicalId":13559,"journal":{"name":"Industrial laboratory. Diagnostics of materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141797392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-27DOI: 10.26896/1028-6861-2024-90-7-32-39
N. Y. Komarovsky, E. O. Zhuravlev, E. V. Molodtsova, A. V. Kudrya, R. Kozlov, A. G. Belov, S. S. Kormilitsina
The method of selective etching is used to assess the structural imperfection (dislocation density) of single crystals in production conditions due to high informativity and rather low labor consumption. However, the interpretation of the data obtained may differ depending on the choice of the type of regulatory documentation. We present the results of determining the criterion of morphological classification of etch pits using digital image processing. InSb (111) single crystals grown by the Czochralski method and doped with tellurium were analyzed. It was found by the method of sequential selective etching that the island-shaped pits on the surface of InSb (111), are highly likely to be dislocation in nature, regardless of their size. In turn, the clusters of pits of «regular» shape, disappearing in the course of repeated etching, probably arise in the places where point defects come to the surface and are not associated with the formation of Lomer-Cottrell barriers or other dislocation clusters. A criterion for differentiation of etching pits by determining the value of the average pixel intensity is proposed on the basis of brightness field analysis. The results obtained can be used in manufacturing structures for matrix and linear photodetectors, as well as in optimizing process parameters of the single crystal growth by the Czochralski method.
{"title":"Determination of the criterion for the morphological classification of etching pits formed in InSb single crystals grown by the Czochralski method in the crystallographic direction [111] and doped with tellurium","authors":"N. Y. Komarovsky, E. O. Zhuravlev, E. V. Molodtsova, A. V. Kudrya, R. Kozlov, A. G. Belov, S. S. Kormilitsina","doi":"10.26896/1028-6861-2024-90-7-32-39","DOIUrl":"https://doi.org/10.26896/1028-6861-2024-90-7-32-39","url":null,"abstract":"The method of selective etching is used to assess the structural imperfection (dislocation density) of single crystals in production conditions due to high informativity and rather low labor consumption. However, the interpretation of the data obtained may differ depending on the choice of the type of regulatory documentation. We present the results of determining the criterion of morphological classification of etch pits using digital image processing. InSb (111) single crystals grown by the Czochralski method and doped with tellurium were analyzed. It was found by the method of sequential selective etching that the island-shaped pits on the surface of InSb (111), are highly likely to be dislocation in nature, regardless of their size. In turn, the clusters of pits of «regular» shape, disappearing in the course of repeated etching, probably arise in the places where point defects come to the surface and are not associated with the formation of Lomer-Cottrell barriers or other dislocation clusters. A criterion for differentiation of etching pits by determining the value of the average pixel intensity is proposed on the basis of brightness field analysis. The results obtained can be used in manufacturing structures for matrix and linear photodetectors, as well as in optimizing process parameters of the single crystal growth by the Czochralski method.","PeriodicalId":13559,"journal":{"name":"Industrial laboratory. Diagnostics of materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141797626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-27DOI: 10.26896/1028-6861-2024-90-7-56-67
L. S. Botvina, E. N. Belecky, Y. Demina, I. A. Ivanov
The kinetics of short cracks in 316L steel samples made by selective laser melting was studied. The structural sensitivity of such cracks, which form on technological defects at the early stage of fatigue is noted. The cracks develop predominantly along the fusion boundaries and slow down their growth at the boundaries of the melt pools. An increase in the crack opening of arrested cracks lead to the formation of a plastic zone at their tips, localization of deformation, a decrease in opening and continued growth with an increase in the number of cycles. The alternation of the processes of propagation and deceleration of short cracks during loading is reflected in the kinetic diagram of fatigue failure which has rate growth thresholds with spacing between them being close to the scanning step during steel manufacturing. The diagram is described by the Paris equation with the same exponent at the growth stage of both short and long cracks. The plotted fatigue curve was compared with fatigue curves for the same material produced by traditional and additive methods. It was shown that the plotted fatigue curve, as well as the fatigue curves for similar materials taken from literary sources, lie much lower than the fatigue curve for the same steel obtained by the traditional method. However, the use of optimal manufacturing modes, as well as subsequent heat treatment, leads to the fatigue characteristics of «additive» steel being similar to those of steels produced by the traditional method. The macro- and microrelief of the fracture surfaces of the samples was studied, the stages of stable and accelerated crack growth were identified, the crack lengths at fracture surfaces corresponding to these stages were evaluated and the predominate fracture mechanisms at each stage were described. It is shown that the observed knee point in the fatigue curve is accompanied by an increase in the damage of the lateral surface of the samples with an increase in the stress amplitude and transition to a more ductile fracture relief, which is explained by the switch from the plane-strain state to a plane-stressed state of the sample material realizing at the tip of the macrocrack.
{"title":"Fatigue fracture of 316L steel manufactured by selective laser melting method","authors":"L. S. Botvina, E. N. Belecky, Y. Demina, I. A. Ivanov","doi":"10.26896/1028-6861-2024-90-7-56-67","DOIUrl":"https://doi.org/10.26896/1028-6861-2024-90-7-56-67","url":null,"abstract":"The kinetics of short cracks in 316L steel samples made by selective laser melting was studied. The structural sensitivity of such cracks, which form on technological defects at the early stage of fatigue is noted. The cracks develop predominantly along the fusion boundaries and slow down their growth at the boundaries of the melt pools. An increase in the crack opening of arrested cracks lead to the formation of a plastic zone at their tips, localization of deformation, a decrease in opening and continued growth with an increase in the number of cycles. The alternation of the processes of propagation and deceleration of short cracks during loading is reflected in the kinetic diagram of fatigue failure which has rate growth thresholds with spacing between them being close to the scanning step during steel manufacturing. The diagram is described by the Paris equation with the same exponent at the growth stage of both short and long cracks. The plotted fatigue curve was compared with fatigue curves for the same material produced by traditional and additive methods. It was shown that the plotted fatigue curve, as well as the fatigue curves for similar materials taken from literary sources, lie much lower than the fatigue curve for the same steel obtained by the traditional method. However, the use of optimal manufacturing modes, as well as subsequent heat treatment, leads to the fatigue characteristics of «additive» steel being similar to those of steels produced by the traditional method. The macro- and microrelief of the fracture surfaces of the samples was studied, the stages of stable and accelerated crack growth were identified, the crack lengths at fracture surfaces corresponding to these stages were evaluated and the predominate fracture mechanisms at each stage were described. It is shown that the observed knee point in the fatigue curve is accompanied by an increase in the damage of the lateral surface of the samples with an increase in the stress amplitude and transition to a more ductile fracture relief, which is explained by the switch from the plane-strain state to a plane-stressed state of the sample material realizing at the tip of the macrocrack.","PeriodicalId":13559,"journal":{"name":"Industrial laboratory. Diagnostics of materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141797959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-27DOI: 10.26896/1028-6861-2024-90-7-76-83
A. Monakhov, D. V. Grinevich, N. O. Yakovlev
A sample configuration with a specified distribution of residual stresses in depth was developed to elaborate modes for studying residual stresses using mechanical and physical methods. The sample formation technique is based on non-uniform plastic deformation of an aluminum beam of rectangular cross section according to the pure bending scheme. The control of the deformed state during loading was performed on the end surface of the sample by the field of normal deformations obtained using a digital image correlation system. The depth of the plastically deformed layer was 1.3 mm. The theoretical distribution of residual stresses obtained as a result of unloading of a plastically deformed sample was determined from the results of a numerical calculation of a finite element model, with allowance for the physical and mechanical characteristics, elastic-plastic hardening, as well as the deformation curve in true coordinates obtained as a result of uniaxial tension on elementary samples. A study of residual stresses inhomogeneous in depth was carried out by drilling holes in accordance with ASTM E837 on two opposite sides of the sample: the region of tension under loading and the area of compression, respectively. The control of the deformation response resulted from drilling was recorded using three-axis strain gauge rosettes. The results of the actual measurement of the longitudinal component of residual stresses were compared with their theoretical distribution obtained by a numerical method. The root-mean-square error in measuring residual stresses, relative to their theoretical distribution, for an aluminum alloy sample reaches 18.7 MPa. It should be noted that largest measurement errors were recorded at small depths, since they are characterized by small values of deformations comparable to the value of shot noise.
{"title":"Evaluation of the errors of measuring residual stresses by the hole drilling method","authors":"A. Monakhov, D. V. Grinevich, N. O. Yakovlev","doi":"10.26896/1028-6861-2024-90-7-76-83","DOIUrl":"https://doi.org/10.26896/1028-6861-2024-90-7-76-83","url":null,"abstract":"A sample configuration with a specified distribution of residual stresses in depth was developed to elaborate modes for studying residual stresses using mechanical and physical methods. The sample formation technique is based on non-uniform plastic deformation of an aluminum beam of rectangular cross section according to the pure bending scheme. The control of the deformed state during loading was performed on the end surface of the sample by the field of normal deformations obtained using a digital image correlation system. The depth of the plastically deformed layer was 1.3 mm. The theoretical distribution of residual stresses obtained as a result of unloading of a plastically deformed sample was determined from the results of a numerical calculation of a finite element model, with allowance for the physical and mechanical characteristics, elastic-plastic hardening, as well as the deformation curve in true coordinates obtained as a result of uniaxial tension on elementary samples. A study of residual stresses inhomogeneous in depth was carried out by drilling holes in accordance with ASTM E837 on two opposite sides of the sample: the region of tension under loading and the area of compression, respectively. The control of the deformation response resulted from drilling was recorded using three-axis strain gauge rosettes. The results of the actual measurement of the longitudinal component of residual stresses were compared with their theoretical distribution obtained by a numerical method. The root-mean-square error in measuring residual stresses, relative to their theoretical distribution, for an aluminum alloy sample reaches 18.7 MPa. It should be noted that largest measurement errors were recorded at small depths, since they are characterized by small values of deformations comparable to the value of shot noise.","PeriodicalId":13559,"journal":{"name":"Industrial laboratory. Diagnostics of materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141798597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-27DOI: 10.26896/1028-6861-2024-90-7-17-26
T. A. Grigoryeva, A. Gorshkov
A methodology for determining priority phthalates (PP) at trace concentrations in surface waters with a background pollution level has been validated. Lake Baikal, the largest natural reservoir that retains up to 20% of the world’s fresh surface waters, was chosen as a natural model for the study. Baikal is characterized by a minimal content of suspended organic matter, a low degree of mineralization and a background level of organic pollutants. Four priority phthalates were found in Baikal water: dimethyl phthalate, diethyl phthalate di-n-butyl phthalate and di-(2-ethylhexyl) phthalate present in the concentration range from 0.01 to 0.66 μg/liter. The method for phthalate determination includes a single liquid-liquid extraction of phthalates (Vsample = 1 liter) and direct analysis of the extracts by GC-MS. Considering the minimum content of suspended particles in water and the use of high sensitivity of the mass spectrometry, the stages of sample filtration and concentration of extracts are excluded from the procedure. Deuterated phthalates are used as surrogate internal standards for the quantitative determination of priority phthalates. The laboratory background of phthalates was assessed using reagent-blank methods, exhaustive multiple extraction and subsequent exclusion of the resulting value from the determination result as a systematic error. The limits of phthalate determination (0.01 – 0.17 μg/liter) and the error of determination (±δ from 12 to 38%) were assessed in the concentration range from 0.01 to 0.66 μg/liter. The method was validated during monitoring of persistent organic pollutants in water of Lake Baikal for the period 2015 – 2023.
{"title":"Validation of the method for determining priority phthalates by GC-MS at trace concentrations in surface water with a background pollution level","authors":"T. A. Grigoryeva, A. Gorshkov","doi":"10.26896/1028-6861-2024-90-7-17-26","DOIUrl":"https://doi.org/10.26896/1028-6861-2024-90-7-17-26","url":null,"abstract":"A methodology for determining priority phthalates (PP) at trace concentrations in surface waters with a background pollution level has been validated. Lake Baikal, the largest natural reservoir that retains up to 20% of the world’s fresh surface waters, was chosen as a natural model for the study. Baikal is characterized by a minimal content of suspended organic matter, a low degree of mineralization and a background level of organic pollutants. Four priority phthalates were found in Baikal water: dimethyl phthalate, diethyl phthalate di-n-butyl phthalate and di-(2-ethylhexyl) phthalate present in the concentration range from 0.01 to 0.66 μg/liter. The method for phthalate determination includes a single liquid-liquid extraction of phthalates (Vsample = 1 liter) and direct analysis of the extracts by GC-MS. Considering the minimum content of suspended particles in water and the use of high sensitivity of the mass spectrometry, the stages of sample filtration and concentration of extracts are excluded from the procedure. Deuterated phthalates are used as surrogate internal standards for the quantitative determination of priority phthalates. The laboratory background of phthalates was assessed using reagent-blank methods, exhaustive multiple extraction and subsequent exclusion of the resulting value from the determination result as a systematic error. The limits of phthalate determination (0.01 – 0.17 μg/liter) and the error of determination (±δ from 12 to 38%) were assessed in the concentration range from 0.01 to 0.66 μg/liter. The method was validated during monitoring of persistent organic pollutants in water of Lake Baikal for the period 2015 – 2023.","PeriodicalId":13559,"journal":{"name":"Industrial laboratory. Diagnostics of materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141797964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-27DOI: 10.26896/1028-6861-2024-90-7-40-47
S. V. Lomov, A. I. Morkovkin
A mechanical digital twin (a mechanical finite-element model) of an asphalt concrete sample has been developed in the framework of a project for recycling polymer composite materials with fibrous reinforcement (fiberglass) as an alternative for crushed stone in the asphalt concrete production. A methodology of using X-ray computed tomography (XCT) for analysis of the asphalt concrete microstructure and calculation of the mechanical properties is developed. The data processing chain for developing a digital twin of the asphalt concrete microstructure, based on X-ray micro-computed tomography (XCT) image includes the following steps: 1) image enhancement; 2) image segmentation; 3) analysis of the morphology of pores and solid particles; 4) transformation of the segmented image into a voxels-based finite element (FE) model. It is demonstrated that the XCT resolution of 40 μm is sufficient for a reliable identification of microstructural parameters, i.e., volume fractions of the components, distributions of voids (pores) in size, shape and spatial position, as well as distributions of the crushed brittle additives (fiberglass chips) in size. The FE model constitutes a digital twin of the material, and, after specifying the characteristics of the material components, can be used for simulation of the thermomechanical and functional properties of the material. The developed procedure is exemplified in the calculation of statistics of the compression and shear moduli of the asphalt concrete with addition of crushed fiberglass particles. The dependence of the calculated elastic properties on the size of the digital twin is studied. It is shown that a model size of 10 mm and more is sufficient for the microstructural representativity and calculation of the homogenization characteristics. The results can be used for analysis of the microstructure and structure-dependent thermomechanical properties of asphalt concrete. The developed finite element model can be used for modelling of the visco-elastic response of asphalt concrete and its behavior under cyclic loading.
沥青混凝土样品的机械数字孪生（机械有限元模型）是在回收利用带有纤维增强材料（玻璃纤维）的聚合物复合材料项目框架内开发的，该材料在沥青混凝土生产中可替代碎石。开发了使用 X 射线计算机断层扫描（XCT）分析沥青混凝土微观结构和计算机械性能的方法。基于 X 射线微计算机断层扫描 (XCT) 图像的沥青混凝土微观结构数字孪生数据处理链包括以下步骤：1) 图像增强；2) 图像分割；3) 孔隙和固体颗粒形态分析；4) 将分割图像转换为基于体素的有限元 (FE) 模型。结果表明，40 微米的 XCT 分辨率足以可靠地识别微观结构参数，即成分的体积分数、空隙（孔隙）的大小、形状和空间位置分布，以及破碎脆性添加剂（玻璃纤维碎片）的大小分布。FE 模型是材料的数字孪生模型，在指定材料成分的特性后，可用于模拟材料的热力学和功能特性。在计算添加了碎玻璃纤维颗粒的沥青混凝土的压缩和剪切模量统计数据时，对所开发的程序进行了举例说明。研究了计算弹性特性与数字孪生体尺寸的关系。结果表明，10 毫米及以上的模型尺寸足以代表微观结构和计算均匀化特征。研究结果可用于分析沥青混凝土的微观结构和与结构相关的热力学特性。所开发的有限元模型可用于模拟沥青混凝土的粘弹性响应及其在循环荷载下的行为。
{"title":"Study of the microstructure of asphalt concrete using X-ray computed tomography","authors":"S. V. Lomov, A. I. Morkovkin","doi":"10.26896/1028-6861-2024-90-7-40-47","DOIUrl":"https://doi.org/10.26896/1028-6861-2024-90-7-40-47","url":null,"abstract":"A mechanical digital twin (a mechanical finite-element model) of an asphalt concrete sample has been developed in the framework of a project for recycling polymer composite materials with fibrous reinforcement (fiberglass) as an alternative for crushed stone in the asphalt concrete production. A methodology of using X-ray computed tomography (XCT) for analysis of the asphalt concrete microstructure and calculation of the mechanical properties is developed. The data processing chain for developing a digital twin of the asphalt concrete microstructure, based on X-ray micro-computed tomography (XCT) image includes the following steps: 1) image enhancement; 2) image segmentation; 3) analysis of the morphology of pores and solid particles; 4) transformation of the segmented image into a voxels-based finite element (FE) model. It is demonstrated that the XCT resolution of 40 μm is sufficient for a reliable identification of microstructural parameters, i.e., volume fractions of the components, distributions of voids (pores) in size, shape and spatial position, as well as distributions of the crushed brittle additives (fiberglass chips) in size. The FE model constitutes a digital twin of the material, and, after specifying the characteristics of the material components, can be used for simulation of the thermomechanical and functional properties of the material. The developed procedure is exemplified in the calculation of statistics of the compression and shear moduli of the asphalt concrete with addition of crushed fiberglass particles. The dependence of the calculated elastic properties on the size of the digital twin is studied. It is shown that a model size of 10 mm and more is sufficient for the microstructural representativity and calculation of the homogenization characteristics. The results can be used for analysis of the microstructure and structure-dependent thermomechanical properties of asphalt concrete. The developed finite element model can be used for modelling of the visco-elastic response of asphalt concrete and its behavior under cyclic loading.","PeriodicalId":13559,"journal":{"name":"Industrial laboratory. Diagnostics of materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141798223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-27DOI: 10.26896/1028-6861-2024-90-7-8-16
A. N. Zhilicheva, G. Pashkova, A. V. Karkhova, N. N. Ukhova, V. Chubarov
The quality of the determination of S, Ni, Cu in copper-nickel sulfide ores was assessed in the framework of the program for interlaboratory comparative tests (ICT) using total reflection X-ray fluorescence analysis (TXRF) taking into account the criteria for methods for determining the chemical composition of mineral raw materials. Certified TXRF techniques for the analysis of mineral materials are absent, so the interlaboratory comparison test was used to control and improve the accuracy of measurements by TXRF. Powdered ore samples were prepared as suspensions by wet grinding: 100 mg of the powder, 4 ml of ultra-pure water and 250 μl of the Ga standard solution were milled using 20 g of ZrO2 balls 1 mm in diameter in the mixing mill for 10 minutes at a frequency of 20 Hz. The ratio of the intensities of the characteristic lines of the analyzed elements and the Ga internal standard was chosen as an analytical signal. To plot calibration curves, a set of ore reference samples was analyzed using certified procedures (atomic absorption spectrometry for Cu, Ni, gravimetry for S). The quality of the TXRF analysis was assessed by the value of Z-criterion. The measurement error did not exceed 5 rel. %. The relative percentage differences between the TXRF results and the results obtained in the interlaboratory study was less than 10%. The described method can be used for rapid analysis of copper-nickel sulfide ores.
{"title":"Determination of S, Ni, Cu in copper-nickel sulfide ores by total reflection X-ray fluorescence analysis: experience of participation in the interlaboratory comparisons","authors":"A. N. Zhilicheva, G. Pashkova, A. V. Karkhova, N. N. Ukhova, V. Chubarov","doi":"10.26896/1028-6861-2024-90-7-8-16","DOIUrl":"https://doi.org/10.26896/1028-6861-2024-90-7-8-16","url":null,"abstract":"The quality of the determination of S, Ni, Cu in copper-nickel sulfide ores was assessed in the framework of the program for interlaboratory comparative tests (ICT) using total reflection X-ray fluorescence analysis (TXRF) taking into account the criteria for methods for determining the chemical composition of mineral raw materials. Certified TXRF techniques for the analysis of mineral materials are absent, so the interlaboratory comparison test was used to control and improve the accuracy of measurements by TXRF. Powdered ore samples were prepared as suspensions by wet grinding: 100 mg of the powder, 4 ml of ultra-pure water and 250 μl of the Ga standard solution were milled using 20 g of ZrO2 balls 1 mm in diameter in the mixing mill for 10 minutes at a frequency of 20 Hz. The ratio of the intensities of the characteristic lines of the analyzed elements and the Ga internal standard was chosen as an analytical signal. To plot calibration curves, a set of ore reference samples was analyzed using certified procedures (atomic absorption spectrometry for Cu, Ni, gravimetry for S). The quality of the TXRF analysis was assessed by the value of Z-criterion. The measurement error did not exceed 5 rel. %. The relative percentage differences between the TXRF results and the results obtained in the interlaboratory study was less than 10%. The described method can be used for rapid analysis of copper-nickel sulfide ores.","PeriodicalId":13559,"journal":{"name":"Industrial laboratory. Diagnostics of materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141798270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-27DOI: 10.26896/1028-6861-2024-90-7-84-92
A. A. Abdushukurov, N. S. Nurmukhamedova, S. A. Erisbaev
The accuracy of statistical estimates of unknown distribution parameters depends not only on the bulk of sampling data but also on the method of data acquisition. The information content of experimental data is one of the basic requirements. Problems of mathematical statistics, in particular parametric estimation based on censored observations, have specific features. Typical representatives of models of incomplete observations on a straight line are models of random censoring, competing risks of (single, multiple) random censoring. The purpose of this study is to show that censoring does not always lead to loss of (Fisher) information. It is shown that if censoring is informative, i.e., the distribution of censoring random variables depends on the same parameter, it is possible to specify a model where information can be preserved due to censoring. On the contrary, if the censoring is not informative, then the loss of information is inevitable. The Cramer – Rao efficiency was taken as a criterion for the quality of the assessment, whereas the Fisher information was taken as the criterion for information about the unknown parameter.
{"title":"Fisher information contained in incomplete observations","authors":"A. A. Abdushukurov, N. S. Nurmukhamedova, S. A. Erisbaev","doi":"10.26896/1028-6861-2024-90-7-84-92","DOIUrl":"https://doi.org/10.26896/1028-6861-2024-90-7-84-92","url":null,"abstract":"The accuracy of statistical estimates of unknown distribution parameters depends not only on the bulk of sampling data but also on the method of data acquisition. The information content of experimental data is one of the basic requirements. Problems of mathematical statistics, in particular parametric estimation based on censored observations, have specific features. Typical representatives of models of incomplete observations on a straight line are models of random censoring, competing risks of (single, multiple) random censoring. The purpose of this study is to show that censoring does not always lead to loss of (Fisher) information. It is shown that if censoring is informative, i.e., the distribution of censoring random variables depends on the same parameter, it is possible to specify a model where information can be preserved due to censoring. On the contrary, if the censoring is not informative, then the loss of information is inevitable. The Cramer – Rao efficiency was taken as a criterion for the quality of the assessment, whereas the Fisher information was taken as the criterion for information about the unknown parameter.","PeriodicalId":13559,"journal":{"name":"Industrial laboratory. Diagnostics of materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141798467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-27DOI: 10.26896/1028-6861-2024-90-7-5-7
A. I. Orlov
.
.
{"title":"The paradigm shift in mathematical methods of research","authors":"A. I. Orlov","doi":"10.26896/1028-6861-2024-90-7-5-7","DOIUrl":"https://doi.org/10.26896/1028-6861-2024-90-7-5-7","url":null,"abstract":"<jats:p>.</jats:p>","PeriodicalId":13559,"journal":{"name":"Industrial laboratory. Diagnostics of materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141797794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-27DOI: 10.26896/1028-6861-2024-90-7-68-75
M. Gadenin
Fatigue and long static damages to the majority of high-loaded units develop under repeated stresses and strains of large amplitudes in elastic and elastoplastic regions at a low number of the main cycles and superimposition of dynamic stresses of significantly smaller value with higher frequencies which results in the so-called two-frequency modes of loading. It is shown that in the region of elevated and high temperatures, which determine the manifestation of temperature and time effects in the material, parameters of the rate and duration of deformation which enter the basic equation for determination of the fatigue life through the frequency and time of loading become the most significant parameters determining the fracture process. The results of theoretical and experimental study carried out on nickel superalloy specimens under a hard mode of loading and high temperatures have shown that estimation of the strength and fatigue life in this case for the single-frequency and two-frequency modes of loading can be performed on the basis of the analysis of strain parameters and diagrams of cyclic elastoplastic deformation using the deformation-kinetic criterion of summation of damages accumulated in the material. A decrease in the fatigue life under two-frequency mode of loading and the possibility of estimating it using the specified criterion and corresponding dependences with the introduction of the parameters of frequency/amplitude ratios of the strains (both full and that imposed on the main process) is experimentally proved. The calculated dependences include the parameters of temperature conditions, frequency and duration of loading which allows (when assessing damage from low-frequency and high-frequency components of cyclic strains) taking into account the effects of cyclicity and time of loading, as well as the existence of a variable coefficient of the asymmetry of high-frequency cycles of the two-frequency mode during high-temperature cyclic elastoplastic deformation.
{"title":"Low cycle fracture resistance of the superalloy at single- and two-frequency modes of loading","authors":"M. Gadenin","doi":"10.26896/1028-6861-2024-90-7-68-75","DOIUrl":"https://doi.org/10.26896/1028-6861-2024-90-7-68-75","url":null,"abstract":"Fatigue and long static damages to the majority of high-loaded units develop under repeated stresses and strains of large amplitudes in elastic and elastoplastic regions at a low number of the main cycles and superimposition of dynamic stresses of significantly smaller value with higher frequencies which results in the so-called two-frequency modes of loading. It is shown that in the region of elevated and high temperatures, which determine the manifestation of temperature and time effects in the material, parameters of the rate and duration of deformation which enter the basic equation for determination of the fatigue life through the frequency and time of loading become the most significant parameters determining the fracture process. The results of theoretical and experimental study carried out on nickel superalloy specimens under a hard mode of loading and high temperatures have shown that estimation of the strength and fatigue life in this case for the single-frequency and two-frequency modes of loading can be performed on the basis of the analysis of strain parameters and diagrams of cyclic elastoplastic deformation using the deformation-kinetic criterion of summation of damages accumulated in the material. A decrease in the fatigue life under two-frequency mode of loading and the possibility of estimating it using the specified criterion and corresponding dependences with the introduction of the parameters of frequency/amplitude ratios of the strains (both full and that imposed on the main process) is experimentally proved. The calculated dependences include the parameters of temperature conditions, frequency and duration of loading which allows (when assessing damage from low-frequency and high-frequency components of cyclic strains) taking into account the effects of cyclicity and time of loading, as well as the existence of a variable coefficient of the asymmetry of high-frequency cycles of the two-frequency mode during high-temperature cyclic elastoplastic deformation.","PeriodicalId":13559,"journal":{"name":"Industrial laboratory. Diagnostics of materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141797916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：