Chunyang Zhang, Tao Tan, Bo Ke, Bingde Ma, Bibo Dai, Zhiheng Fang, Ercheng Zhao
The freeze-thaw (FT) damage characteristics of granite after different FT cycles were studied using computed tomography (CT) images. The three-dimensional (3D) volume numbers in the image were extracted to obtain the 3D pore structure of representative volume elements (RVEs) of granite under different FT cycles. The CT images of granite after 80 FT cycles were selected to draw reference lines for quantitative analysis of the distribution of meso-cracks in granite after FT cycles. Subsequently, a finite element model was established to explore the mechanical properties of minerals in granite during a single FT process. The results show that the FT damage inside the granite exhibits fracture characteristics, and the number of internal cracks, cracks area, and voxel porosity increase with the increase of FT cycles. After 80 FT cycles, the distribution of meso-cracks on the cross-section of granite exhibits significant anisotropy, and the distribution density and variation coefficient of meso-cracks vary with the dip direction angle of the reference line. The maximum principal stress and strain in the finite element model are negatively related to temperature. The maximum principal stress and strain of biotite minerals are consistently higher than those of feldspar and mica during FT cycles. The results can provide a reference for exploring the internal mechanism of the weakening of mechanical properties of granite microstructure caused by FT damage in cold regions.
利用计算机断层扫描（CT）图像研究了不同冻融循环后花岗岩的冻融（FT）损伤特征。提取图像中的三维（3D）体积数，得到不同冻融循环下花岗岩代表性体积元素（RVE）的三维孔隙结构。选择 80 次 FT 循环后的花岗岩 CT 图像绘制参考线，用于定量分析 FT 循环后花岗岩中观裂纹的分布情况。随后，建立了有限元模型，以探讨花岗岩在单次 FT 过程中的矿物力学性能。结果表明，花岗岩内部的 FT 损伤表现出断裂特征，内部裂缝数量、裂缝面积和体孔率随着 FT 循环次数的增加而增加。经过 80 次 FT 循环后，花岗岩截面上的中裂纹分布呈现出明显的各向异性，中裂纹的分布密度和变化系数随基准线的倾角变化而变化。有限元模型中的最大主应力和应变与温度呈负相关。在 FT 循环过程中，生物岩矿物的最大主应力和应变始终高于长石和云母。研究结果可为探索寒冷地区花岗岩微结构因 FT 破坏而导致力学性能减弱的内在机理提供参考。
{"title":"CT measurement of damage characteristics of meso-structure of freeze-thawed granite in cold regions and preliminary exploration of its mechanical behavior during a single freeze-thaw process","authors":"Chunyang Zhang, Tao Tan, Bo Ke, Bingde Ma, Bibo Dai, Zhiheng Fang, Ercheng Zhao","doi":"10.1515/arh-2023-0106","DOIUrl":"https://doi.org/10.1515/arh-2023-0106","url":null,"abstract":"The freeze-thaw (FT) damage characteristics of granite after different FT cycles were studied using computed tomography (CT) images. The three-dimensional (3D) volume numbers in the image were extracted to obtain the 3D pore structure of representative volume elements (RVEs) of granite under different FT cycles. The CT images of granite after 80 FT cycles were selected to draw reference lines for quantitative analysis of the distribution of meso-cracks in granite after FT cycles. Subsequently, a finite element model was established to explore the mechanical properties of minerals in granite during a single FT process. The results show that the FT damage inside the granite exhibits fracture characteristics, and the number of internal cracks, cracks area, and voxel porosity increase with the increase of FT cycles. After 80 FT cycles, the distribution of meso-cracks on the cross-section of granite exhibits significant anisotropy, and the distribution density and variation coefficient of meso-cracks vary with the dip direction angle of the reference line. The maximum principal stress and strain in the finite element model are negatively related to temperature. The maximum principal stress and strain of biotite minerals are consistently higher than those of feldspar and mica during FT cycles. The results can provide a reference for exploring the internal mechanism of the weakening of mechanical properties of granite microstructure caused by FT damage in cold regions.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"7 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138563182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jiaqiang Zou, Hao Chen, Yu-hong Jiang, W. Zhang, Aihua Liu
Abstract The purpose of this article is to provide an effective approach to evaluate slope stability in real-time in a reservoir area, which is significant for carrying out risk management for landslide disaster prevention in various engineering practices. A comprehensive idea for stability estimation of bank slope under the influence of rainfall or the reservoir water level is presented in this work. Slope stability analysis and back analysis of soil parameters are both included based on numerical simulation. The mechanical parameters of the bank slope were first back-analyzed using particle swarm optimization (PSO), and real-time stability analysis with high accuracy and efficiency was then established based on multiple continuously monitored displacements. Two case studies were carried out in this study. The results show that (1) based on the real-time monitored displacement and numerical simulation, the mechanical parameters of the slope can be reasonably retrieved through PSO; and (2) based on the inverse mechanical parameters, the safety factors of the slope can be numerically obtained, so that the real-time estimation of slope stability can be realized.
{"title":"An effective method for real-time estimation of slope stability with numerical back analysis based on particle swarm optimization","authors":"Jiaqiang Zou, Hao Chen, Yu-hong Jiang, W. Zhang, Aihua Liu","doi":"10.1515/arh-2022-0143","DOIUrl":"https://doi.org/10.1515/arh-2022-0143","url":null,"abstract":"Abstract The purpose of this article is to provide an effective approach to evaluate slope stability in real-time in a reservoir area, which is significant for carrying out risk management for landslide disaster prevention in various engineering practices. A comprehensive idea for stability estimation of bank slope under the influence of rainfall or the reservoir water level is presented in this work. Slope stability analysis and back analysis of soil parameters are both included based on numerical simulation. The mechanical parameters of the bank slope were first back-analyzed using particle swarm optimization (PSO), and real-time stability analysis with high accuracy and efficiency was then established based on multiple continuously monitored displacements. Two case studies were carried out in this study. The results show that (1) based on the real-time monitored displacement and numerical simulation, the mechanical parameters of the slope can be reasonably retrieved through PSO; and (2) based on the inverse mechanical parameters, the safety factors of the slope can be numerically obtained, so that the real-time estimation of slope stability can be realized.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48615941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Almisned, Z. Khattari, El Rabaa, Y. Rammah, Duygu Sen Baykal, G. Kilic, H. Zakaly, A. Ene, H. Tekin
Abstract We report a correlation outcome for mechanical and gamma-ray transmission properties of tellurite glasses by increasing tungsten(vi) oxide concentration in glass structure. The mechanical properties as well as Poisson’s ratio (σ) of the studied glasses are estimated by applying Makishima–Mackenzie model. Gamma-ray attenuation properties using various fundamental parameters are determined in 0.015–15 MeV energy range. Poisson’s ratio (σ) decreased from 0.43017 to 0.42711, while all elastic moduli increased linearly with the molar increment of either [WO3] or [TeO2] in the molecular structure of the glass network. Moreover, gamma-ray attenuation properties are enhanced as a function of increasing WO3 substitution amount from 30 to 50% mol in the glass structure. Half-value layer values at 15 MeV are found to be between 2.648 and 2.8614 cm. I4 samples with a composition of 20TeO2–50WO3–30GdF3 and density of 6.0530 g/cm3 was found to have superior material properties in terms of elastic and gamma-ray attenuation properties. It can be concluded that maximized WO3 contribution into the tellurite glasses may be considered as a critical tool in terms of establishing a symmetry between mechanical and gamma-ray attenuation properties for high-density tellurite glasses for their potential utilization in nuclear waste management, radiation shielding, and radioactive source transportation purposes.
{"title":"Tailoring a symmetry for material properties of tellurite glasses through tungsten(vi) oxide addition: Mechanical properties and gamma-ray transmissions properties","authors":"G. Almisned, Z. Khattari, El Rabaa, Y. Rammah, Duygu Sen Baykal, G. Kilic, H. Zakaly, A. Ene, H. Tekin","doi":"10.1515/arh-2022-0151","DOIUrl":"https://doi.org/10.1515/arh-2022-0151","url":null,"abstract":"Abstract We report a correlation outcome for mechanical and gamma-ray transmission properties of tellurite glasses by increasing tungsten(vi) oxide concentration in glass structure. The mechanical properties as well as Poisson’s ratio (σ) of the studied glasses are estimated by applying Makishima–Mackenzie model. Gamma-ray attenuation properties using various fundamental parameters are determined in 0.015–15 MeV energy range. Poisson’s ratio (σ) decreased from 0.43017 to 0.42711, while all elastic moduli increased linearly with the molar increment of either [WO3] or [TeO2] in the molecular structure of the glass network. Moreover, gamma-ray attenuation properties are enhanced as a function of increasing WO3 substitution amount from 30 to 50% mol in the glass structure. Half-value layer values at 15 MeV are found to be between 2.648 and 2.8614 cm. I4 samples with a composition of 20TeO2–50WO3–30GdF3 and density of 6.0530 g/cm3 was found to have superior material properties in terms of elastic and gamma-ray attenuation properties. It can be concluded that maximized WO3 contribution into the tellurite glasses may be considered as a critical tool in terms of establishing a symmetry between mechanical and gamma-ray attenuation properties for high-density tellurite glasses for their potential utilization in nuclear waste management, radiation shielding, and radioactive source transportation purposes.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47920279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Complex fluids, such as gels, shampoos, and creams, are ubiquitous in the consumer product industry. However, little information is available on their discharge from consumer packaging, often resulting in a considerable heel, i.e., the residual waste material after the discharge process is complete. Here, we used rheological analysis and particle image velocimetry (PIV) to investigate the discharge of rheologically different fluids from a dispensing bottle provided with a modified hand pump. The fluids were described in terms of rheological parameters established by fitting rheometric data with the Carreau equation. The effect of operational parameters was also studied, which included the dip tube diameter, suction pressure, and volumetric flow rate. The data were also analyzed in terms of the dimensionless region of interest (ROI), which captures the relative “high-velocity” region in the fluid during the discharge process and is measured directly using PIV. Both rheological and operational parameters affect the heel at the end of the discharge process. The results presented here enable predicting the heel either by measuring ROI as in the case of transparent fluids and packages or by making use of the heel correlation with operational and rheological parameters also established in this work. Graphical abstract
{"title":"Analysis of complex fluid discharge from consumer dispensing bottles using rheology and flow visualization","authors":"Baran Teoman, A. Potanin, P. Armenante","doi":"10.1515/arh-2022-0144","DOIUrl":"https://doi.org/10.1515/arh-2022-0144","url":null,"abstract":"Abstract Complex fluids, such as gels, shampoos, and creams, are ubiquitous in the consumer product industry. However, little information is available on their discharge from consumer packaging, often resulting in a considerable heel, i.e., the residual waste material after the discharge process is complete. Here, we used rheological analysis and particle image velocimetry (PIV) to investigate the discharge of rheologically different fluids from a dispensing bottle provided with a modified hand pump. The fluids were described in terms of rheological parameters established by fitting rheometric data with the Carreau equation. The effect of operational parameters was also studied, which included the dip tube diameter, suction pressure, and volumetric flow rate. The data were also analyzed in terms of the dimensionless region of interest (ROI), which captures the relative “high-velocity” region in the fluid during the discharge process and is measured directly using PIV. Both rheological and operational parameters affect the heel at the end of the discharge process. The results presented here enable predicting the heel either by measuring ROI as in the case of transparent fluids and packages or by making use of the heel correlation with operational and rheological parameters also established in this work. Graphical abstract","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45898617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The rapid traffic developments create demands for shallow four-line high-speed railway tunnels in weak soils, while construction technologies of such tunnels have yet to be reported. In this article, the construction schemes for a shallow four-line high-speed railway tunnel with a span of 26.3 m in weak tuff strata are investigated by numerical analysis and in-situ tests. First, 20 construction schemes of the shallow super-large span high-speed railway tunnel are proposed and simulated by the Finite Difference Method, including eight schemes for grade V rocks and 12 schemes for grades IV and III rocks. The mechanical response of grade V rock mass is simulated by the Bolt–Kelvin Mohr–Coulomb rheological model. The influence of construction method, rock grade, area, quantity, and excavation sequence of pilot tunnels on the rock deformation and the internal force of the primary support are comparatively explored. For further analysis, an 8 month field test was conducted to study the optimized effect of the construction scheme. Finally, a suggested construction method selection chart for super-large span tunnels in weak rocks (spans between 17 and 34 m) has been proposed. The research conclusion could provide a reference for building the super-large span tunnel in complex conditions.
{"title":"Research and optimization of tunnel construction scheme for super-large span high-speed railway tunnel in poor tuff strata","authors":"Jianfei Ma, Shaohui He, Xiabing Liu, Jiaxin He","doi":"10.1515/arh-2023-0101","DOIUrl":"https://doi.org/10.1515/arh-2023-0101","url":null,"abstract":"Abstract The rapid traffic developments create demands for shallow four-line high-speed railway tunnels in weak soils, while construction technologies of such tunnels have yet to be reported. In this article, the construction schemes for a shallow four-line high-speed railway tunnel with a span of 26.3 m in weak tuff strata are investigated by numerical analysis and in-situ tests. First, 20 construction schemes of the shallow super-large span high-speed railway tunnel are proposed and simulated by the Finite Difference Method, including eight schemes for grade V rocks and 12 schemes for grades IV and III rocks. The mechanical response of grade V rock mass is simulated by the Bolt–Kelvin Mohr–Coulomb rheological model. The influence of construction method, rock grade, area, quantity, and excavation sequence of pilot tunnels on the rock deformation and the internal force of the primary support are comparatively explored. For further analysis, an 8 month field test was conducted to study the optimized effect of the construction scheme. Finally, a suggested construction method selection chart for super-large span tunnels in weak rocks (spans between 17 and 34 m) has been proposed. The research conclusion could provide a reference for building the super-large span tunnel in complex conditions.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135440219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract In this study, a new scheme for the classification of thickened-fluids based on xanthan gum-cress seed gum was developed. For this purpose, the mechanical characteristics, including steady shear, small amplitude oscillatory shear, large amplitude oscillatory shear, and tribological parameters, were measured and classified into four clusters using the K -means approach. The findings showed that the first cluster contained the highest coefficient of friction value (0.529 ± 0.008), and the fourth cluster comprised the highest consistency coefficient (19.42 ± 0.01 Pa s n ), strain-stiffening ratio (0.42 ± 0.01), yield stress (28.61 ± 0.10 Pa), and frequency dependency of viscous modulus (12.18 ± 0.02). The results also indicated that the classification of in vitro thickened liquid characteristics could be developed based on the interconnection between tribology and rheology. The presented methodology is capable of comparison of test results across the International dysphagia diet standardization initiative and line-spread test.
提出了一种基于黄原胶-芥籽胶的增稠液分类新方案。为此，测量了包括稳态剪切、小振幅振荡剪切、大振幅振荡剪切和摩擦学参数在内的力学特性，并使用K -means方法将其分为四类。结果表明，摩擦系数最高(0.529±0.008)，一致性系数最高(19.42±0.01 Pa s n)，应变加筋比最高(0.42±0.01)，屈服应力最高(28.61±0.10 Pa)，粘滞模量频率依赖性最高(12.18±0.02)。结果还表明，可以基于摩擦学和流变学之间的联系建立体外增稠液特性的分类。所提出的方法能够比较国际吞咽困难饮食标准化倡议和线扩展测试的测试结果。
{"title":"Thickened fluids classification based on the rheological and tribological characteristics","authors":"Parisa Poursani, Seyed M. A. Razavi","doi":"10.1515/arh-2023-0102","DOIUrl":"https://doi.org/10.1515/arh-2023-0102","url":null,"abstract":"Abstract In this study, a new scheme for the classification of thickened-fluids based on xanthan gum-cress seed gum was developed. For this purpose, the mechanical characteristics, including steady shear, small amplitude oscillatory shear, large amplitude oscillatory shear, and tribological parameters, were measured and classified into four clusters using the K -means approach. The findings showed that the first cluster contained the highest coefficient of friction value (0.529 ± 0.008), and the fourth cluster comprised the highest consistency coefficient (19.42 ± 0.01 Pa s n ), strain-stiffening ratio (0.42 ± 0.01), yield stress (28.61 ± 0.10 Pa), and frequency dependency of viscous modulus (12.18 ± 0.02). The results also indicated that the classification of in vitro thickened liquid characteristics could be developed based on the interconnection between tribology and rheology. The presented methodology is capable of comparison of test results across the International dysphagia diet standardization initiative and line-spread test.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136256766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract In order to distinguish the differences in the heterogeneous fractal structure of porous graphite adopted in the filtration and impregnation, the fractal dimensions (FDs) were obtained by the mercury intrusion porosimetry (MIP) to calculate the volumetric FDs of ten graphite samples, following the fractal theory. The FD expression of the tortuosity along with all the parameters from the MIP test was optimized to simplify the calculation. In addition, the percolation evolution process of mercury in the porous media was analyzed based on the data collected in the experiment. According to the analysis conducted, the FDs in the backbone formation regions of samples varied from 2.695 to 2.984, with 2.923 to 2.991 in the percolation regions and 1.224 to 1.544 in the tortuosity. Based on the correlation coefficients ( R 2 ) ({R}^{2}) ranging between 0.906 and 0.999, and the root mean square errors ranging between 0.0001 and 0.0065 mL g−1, a high level of reliability was identified. According to the MIP test, the mercury distribution in porous graphite demonstrated a transitional process from the local aggregation, the gradual expansion, the infinite cluster connection to the global connection.
摘要为了区分多孔石墨在过滤和浸渍过程中所采用的非均匀分形结构的差异，根据分形理论，采用压汞孔隙率计（MIP）获得了分形维数，计算了10个石墨样品的体积分形维数。对弯曲度的FD表达式以及MIP测试的所有参数进行了优化，以简化计算。此外，根据实验数据，分析了汞在多孔介质中的渗流演化过程。根据所进行的分析，样品骨架形成区域的FD在2.695至2.984之间变化，渗透区域的FD为2.923至2.991，曲折度为1.224至1.544。基于范围在0.906和0.999之间的相关系数（R2）（｛R｝^｛2｝），以及范围在0.0001和0.0065之间的均方根误差 mL g−1，确定了高水平的可靠性。根据MIP测试，汞在多孔石墨中的分布表现出从局部聚集、逐渐膨胀、无限团簇连接到全局连接的过渡过程。
{"title":"A study on the fractal and permeability characteristics of coal-based porous graphite for filtration and impregnation","authors":"Qili Wang, J. Wang, Shuwei Yang, Jiarui Sun","doi":"10.1515/arh-2022-0157","DOIUrl":"https://doi.org/10.1515/arh-2022-0157","url":null,"abstract":"Abstract In order to distinguish the differences in the heterogeneous fractal structure of porous graphite adopted in the filtration and impregnation, the fractal dimensions (FDs) were obtained by the mercury intrusion porosimetry (MIP) to calculate the volumetric FDs of ten graphite samples, following the fractal theory. The FD expression of the tortuosity along with all the parameters from the MIP test was optimized to simplify the calculation. In addition, the percolation evolution process of mercury in the porous media was analyzed based on the data collected in the experiment. According to the analysis conducted, the FDs in the backbone formation regions of samples varied from 2.695 to 2.984, with 2.923 to 2.991 in the percolation regions and 1.224 to 1.544 in the tortuosity. Based on the correlation coefficients ( R 2 ) ({R}^{2}) ranging between 0.906 and 0.999, and the root mean square errors ranging between 0.0001 and 0.0065 mL g−1, a high level of reliability was identified. According to the MIP test, the mercury distribution in porous graphite demonstrated a transitional process from the local aggregation, the gradual expansion, the infinite cluster connection to the global connection.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49595267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nan Jiang, Panpan Guo, Hui Zhang, Fangqing Lu, Jian Liu
Abstract Considering the important effect of mineral composition, this article deduces the similarity criterion based on the dimensional method. Similar materials suitable for tuffs with different degrees of weathering in karst areas are made. By virtue of the orthogonal experiment, the mechanical behaviors of the similar materials with various mix proportions are systematically investigated. It provides an important reference and basis for the next proposed model tests on the stability of tuff strata in karst areas. The results indicate that a stable mechanical behavior can be achieved for the similar material made of quartz sand, cement, gypsum, limestone powder, diatomite, red clay, and water. Moreover, it is also found that the aggregate and the binder have an observable influence on the mechanical behavior of the similar material. With an increase in the amount of cement and gypsum, the homogeneity of the sample increases, failure mode in which the specimen shows lateral compression damage. However, with increasing the amount of quartz sand, there is a tendency that a weak structural plane will be generated within the sample. Thus, this similar material can be satisfactorily used for simulating limestone of different weathering degrees in a scaled model test.
{"title":"Mechanical behavior of a new similar material for weathered limestone in karst area: An experimental investigation","authors":"Nan Jiang, Panpan Guo, Hui Zhang, Fangqing Lu, Jian Liu","doi":"10.1515/arh-2022-0154","DOIUrl":"https://doi.org/10.1515/arh-2022-0154","url":null,"abstract":"Abstract Considering the important effect of mineral composition, this article deduces the similarity criterion based on the dimensional method. Similar materials suitable for tuffs with different degrees of weathering in karst areas are made. By virtue of the orthogonal experiment, the mechanical behaviors of the similar materials with various mix proportions are systematically investigated. It provides an important reference and basis for the next proposed model tests on the stability of tuff strata in karst areas. The results indicate that a stable mechanical behavior can be achieved for the similar material made of quartz sand, cement, gypsum, limestone powder, diatomite, red clay, and water. Moreover, it is also found that the aggregate and the binder have an observable influence on the mechanical behavior of the similar material. With an increase in the amount of cement and gypsum, the homogeneity of the sample increases, failure mode in which the specimen shows lateral compression damage. However, with increasing the amount of quartz sand, there is a tendency that a weak structural plane will be generated within the sample. Thus, this similar material can be satisfactorily used for simulating limestone of different weathering degrees in a scaled model test.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46338601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Perovskites are considered the most promising material for the latest generation of solar cells. However, due to the presence of lead in their composition, the development of non-toxic Perovskite cells has become an essential goal to enable their large-scale production. In this work, we have simulated, modeled and optimized the structure of a single solar cell that consists of a non-toxic cesium–tin–iodine CsSnI3 Perovskite absorber with a low band gap energy value of 1.3 eV, between TiO2 and PTAA materials as ETL and HTL layers, respectively. A simulation model describing the charge carrier processes and the effect of interface defect density is presented. Several structures based on alternative ETL and HTL materials are proposed. An optimal device structure is proposed based on the results obtained. An efficiency of 19.92% is obtained with V oc = 0.829 V, J sc = 30.68 mA/cm2 and FF = 73.33% using SnO2 and Spiro-OMeTAD as ETL and HTL materials. However, 29.22% is achieved using the optimal structure as the bottom cell in a tandem configuration.
{"title":"Optimization of lead-free CsSnI3-based perovskite solar cell structure","authors":"Hayat Arbouz","doi":"10.1515/arh-2022-0138","DOIUrl":"https://doi.org/10.1515/arh-2022-0138","url":null,"abstract":"Abstract Perovskites are considered the most promising material for the latest generation of solar cells. However, due to the presence of lead in their composition, the development of non-toxic Perovskite cells has become an essential goal to enable their large-scale production. In this work, we have simulated, modeled and optimized the structure of a single solar cell that consists of a non-toxic cesium–tin–iodine CsSnI3 Perovskite absorber with a low band gap energy value of 1.3 eV, between TiO2 and PTAA materials as ETL and HTL layers, respectively. A simulation model describing the charge carrier processes and the effect of interface defect density is presented. Several structures based on alternative ETL and HTL materials are proposed. An optimal device structure is proposed based on the results obtained. An efficiency of 19.92% is obtained with V oc = 0.829 V, J sc = 30.68 mA/cm2 and FF = 73.33% using SnO2 and Spiro-OMeTAD as ETL and HTL materials. However, 29.22% is achieved using the optimal structure as the bottom cell in a tandem configuration.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45052247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Felix Ellwanger, Christos K. Georgantopoulos, H. Karbstein, Manfred Wilhelm, M. Azad Emin
Abstract The steady-state shear viscosity η ( γ ̇ ) eta (dot{gamma }) is required in controlling processing parameters for the extrusion processing of polymer melts. A new method, the so-called ramp test, is investigated in this study to obtain the steady-state shear viscosity with a closed cavity rheometer (CCR). To verify the method and the accuracy of the CCR data, three commercial polyolefin polymers, a low-density polyethylene (LDPE), a linear low-density polyethylene (LLDPE), and a polybutadiene (PBD), were used as model systems. Measurements of the magnitude of the complex viscosity ∣ η ⁎ ( ω ) ∣ | {eta }^{ast }(omega )| were compared with the steady-state shear viscosity data obtained by capillary rheometer and CCR. Further, time–temperature superposition master curves of the magnitude of the complex viscosity and steady-state shear viscosity obtained by CCR were developed for LLDPE and PBD. The influence of the cavity sealing on the instrument’s accuracy to obtain the steady-state shear viscosity was investigated using the finite element method simulations. Thus, it was shown that the ramp test performed by CCR is a practical method to determine reliable and reproducible data of the steady-state shear viscosity within a wide range of temperatures (T = 50–180°C) for low and high viscous materials ( ∣ η ⁎ ( ω ) ∣ | {eta }^{ast }(omega )| = 1.6–480 kPa s, M w = 144–375 kg mol−1).
摘要控制聚合物熔体挤出加工的工艺参数需要稳态剪切粘度η（γ̇）eta（dot｛gamma｝）。本文研究了一种新的方法，即所谓的斜坡试验，用闭腔流变仪（CCR）获得稳态剪切粘度。为了验证CCR数据的方法和准确性，使用三种商业聚烯烃聚合物，低密度聚乙烯（LDPE）、线性低密度聚乙烯和聚丁二烯（PBD）作为模型系统。将复粘度的大小测量结果与毛细管流变仪和CCR获得的稳态剪切粘度数据进行比较。此外，为LLDPE和PBD开发了CCR获得的复合粘度和稳态剪切粘度大小的时间-温度叠加主曲线。采用有限元模拟方法研究了空腔密封对仪器获得稳态剪切粘度精度的影响。因此，研究表明，CCR进行的斜坡试验是一种实用的方法，可以确定低粘度和高粘度材料在宽温度范围（T=50–180°C）内稳态剪切粘度的可靠且可重复的数据 千帕 s、 M w=144–375 公斤 mol−1）。
{"title":"Application of the ramp test from a closed cavity rheometer to obtain the steady-state shear viscosity η(γ̇)","authors":"Felix Ellwanger, Christos K. Georgantopoulos, H. Karbstein, Manfred Wilhelm, M. Azad Emin","doi":"10.1515/arh-2022-0149","DOIUrl":"https://doi.org/10.1515/arh-2022-0149","url":null,"abstract":"Abstract The steady-state shear viscosity η ( γ ̇ ) eta (dot{gamma }) is required in controlling processing parameters for the extrusion processing of polymer melts. A new method, the so-called ramp test, is investigated in this study to obtain the steady-state shear viscosity with a closed cavity rheometer (CCR). To verify the method and the accuracy of the CCR data, three commercial polyolefin polymers, a low-density polyethylene (LDPE), a linear low-density polyethylene (LLDPE), and a polybutadiene (PBD), were used as model systems. Measurements of the magnitude of the complex viscosity ∣ η ⁎ ( ω ) ∣ | {eta }^{ast }(omega )| were compared with the steady-state shear viscosity data obtained by capillary rheometer and CCR. Further, time–temperature superposition master curves of the magnitude of the complex viscosity and steady-state shear viscosity obtained by CCR were developed for LLDPE and PBD. The influence of the cavity sealing on the instrument’s accuracy to obtain the steady-state shear viscosity was investigated using the finite element method simulations. Thus, it was shown that the ramp test performed by CCR is a practical method to determine reliable and reproducible data of the steady-state shear viscosity within a wide range of temperatures (T = 50–180°C) for low and high viscous materials ( ∣ η ⁎ ( ω ) ∣ | {eta }^{ast }(omega )| = 1.6–480 kPa s, M w = 144–375 kg mol−1).","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46739893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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