Abstract Three sets of indoor model tests of reinforced retaining walls were conducted to study the effects of reinforcing material placement on the displacement of reinforced retaining walls, wall top settlement, earth pressure distribution, and potential failure surface. The test results show that under different reinforcement laying conditions, the maximum horizontal displacement of the lower wall panel appears at the top of the lower retaining wall, and the maximum horizontal displacement of the upper wall panel appears at 0.6H. The settlement of the top of the wall decreases by about 9.1% when the reinforcement is laid in the lower layer. Under the condition of 160 kPa, the maximum horizontal and vertical earth pressures increase by about 19.2 and 12.4%, respectively, and the position of the potential fracture surface of the lower wall moves up to the back of the wall with the position of the reinforcement laying. When the reinforcement is laid in the upper layer, the fracture surface of the upper wall is furthest away from the panel.
{"title":"Reinforcement placement on mechanics and deformation of stepped reinforced retaining wall experimental study of characteristics","authors":"Yalin Zhu, Renyi Chen, Liming Wu, Qianqi Xu, Zijian Zhan","doi":"10.1515/arh-2022-0131","DOIUrl":"https://doi.org/10.1515/arh-2022-0131","url":null,"abstract":"Abstract Three sets of indoor model tests of reinforced retaining walls were conducted to study the effects of reinforcing material placement on the displacement of reinforced retaining walls, wall top settlement, earth pressure distribution, and potential failure surface. The test results show that under different reinforcement laying conditions, the maximum horizontal displacement of the lower wall panel appears at the top of the lower retaining wall, and the maximum horizontal displacement of the upper wall panel appears at 0.6H. The settlement of the top of the wall decreases by about 9.1% when the reinforcement is laid in the lower layer. Under the condition of 160 kPa, the maximum horizontal and vertical earth pressures increase by about 19.2 and 12.4%, respectively, and the position of the potential fracture surface of the lower wall moves up to the back of the wall with the position of the reinforcement laying. When the reinforcement is laid in the upper layer, the fracture surface of the upper wall is furthest away from the panel.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"32 1","pages":"155 - 165"},"PeriodicalIF":1.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45097853","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 Cryogenics has an important influence on industry and science. In this study, optimum working conditions are obtained by applying exergy analysis and local optimization methods to two- and three-stage vapor compression cascade cryogenic cycle. The first and second laws of thermodynamics, exergy analysis, and local optimization methods are applied to the two- and three-stage cascade cryogenic cycle. By considering the needs and demands, it is possible to create new cycles by adding new devices and/or new stages to these cycles. The results of the optimum operating conditions are obtained for the two- and three-stage vapor compression cascade cryogenic cycle. It is seen that to achieve high COP values and high efficiency; it is necessary to reduce the compression ratio of the compressor as much as the fluid allows. For the two-stage cycle, the minimum total work required for cryogenic cooling is around P 7 = 2,400 kPa. The COP value is 0.30 between P 7 = 2,400 and 2,800 kPa, and the maximum exergy efficiency is obtained around 0.235. It is seen operating the first-stage compressor at high pressures increases the total losses of the entire cycle from 7,500 to 18,550 kW. The increase in total exergy losses is around 247%, and operating the first-stage compressor at high pressures increases the exergy efficiency of the entire cycle. The increase in total exergy efficiency is around 160%. When the second-stage compressor is operated at low pressure, the COP value increases by 2%, the exergy efficiency increases by 20%, and the exergy losses decrease by around 40%.
{"title":"Exergy analyses of two and three stage cryogenic cycles","authors":"Musa Atasbak, Arzu Keven, Rabi Karaali̇","doi":"10.1515/arh-2022-0134","DOIUrl":"https://doi.org/10.1515/arh-2022-0134","url":null,"abstract":"Abstract Cryogenics has an important influence on industry and science. In this study, optimum working conditions are obtained by applying exergy analysis and local optimization methods to two- and three-stage vapor compression cascade cryogenic cycle. The first and second laws of thermodynamics, exergy analysis, and local optimization methods are applied to the two- and three-stage cascade cryogenic cycle. By considering the needs and demands, it is possible to create new cycles by adding new devices and/or new stages to these cycles. The results of the optimum operating conditions are obtained for the two- and three-stage vapor compression cascade cryogenic cycle. It is seen that to achieve high COP values and high efficiency; it is necessary to reduce the compression ratio of the compressor as much as the fluid allows. For the two-stage cycle, the minimum total work required for cryogenic cooling is around P 7 = 2,400 kPa. The COP value is 0.30 between P 7 = 2,400 and 2,800 kPa, and the maximum exergy efficiency is obtained around 0.235. It is seen operating the first-stage compressor at high pressures increases the total losses of the entire cycle from 7,500 to 18,550 kW. The increase in total exergy losses is around 247%, and operating the first-stage compressor at high pressures increases the exergy efficiency of the entire cycle. The increase in total exergy efficiency is around 160%. When the second-stage compressor is operated at low pressure, the COP value increases by 2%, the exergy efficiency increases by 20%, and the exergy losses decrease by around 40%.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"32 1","pages":"190 - 204"},"PeriodicalIF":1.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43292894","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}
M. Terashima, Yoko Kotegawa, Meng Sun, Bing Liu, H. Yasui
Abstract Mixing and homogenization in anaerobic digesters are affected by the flow curve of sludge. The aim of this study is to mathematically express the flow curve of dense anaerobically digested sludge behaving as thixotropic and pseudoplastic fluids. Time-dependent changes in two pseudoplastic parameters, i.e., consistency index (µ p) and pseudoplastic index (n), by shear are modeled using a second-order kinetic equation with a coefficient that includes the power function of the shear strain rate. The calculated results are consistent with the experimental results. The kinetic parameters that yielded the ultimate values after shearing were associated with the sludge concentration, unlike the other kinetic parameters.
{"title":"Modeling thixotropic break-down behavior of dense anaerobically digested sludge","authors":"M. Terashima, Yoko Kotegawa, Meng Sun, Bing Liu, H. Yasui","doi":"10.1515/arh-2022-0121","DOIUrl":"https://doi.org/10.1515/arh-2022-0121","url":null,"abstract":"Abstract Mixing and homogenization in anaerobic digesters are affected by the flow curve of sludge. The aim of this study is to mathematically express the flow curve of dense anaerobically digested sludge behaving as thixotropic and pseudoplastic fluids. Time-dependent changes in two pseudoplastic parameters, i.e., consistency index (µ p) and pseudoplastic index (n), by shear are modeled using a second-order kinetic equation with a coefficient that includes the power function of the shear strain rate. The calculated results are consistent with the experimental results. The kinetic parameters that yielded the ultimate values after shearing were associated with the sludge concentration, unlike the other kinetic parameters.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"32 1","pages":"1 - 7"},"PeriodicalIF":1.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47328397","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}
Yu-Dong Fan, Lixun Zhang, Xing-cui Wang, Keyi Wang, Lan Wang, Zhenhan Wang, Feng Xue, Jinghui Zhu, Chao Wang
Abstract The viscosity characteristic is an important factor affecting the holding rate of the meal-assisting instrument. The effects of shear rheological properties, thixotropy, and pasting properties of xanthan gum (XG), guar gum (GG), and thorn bean gum (TBG) in deionized water, berry juice (BJ), and nut lotus root starch (NLRS) were investigated using a rotational viscometer and a water bath, respectively. The results indicated that all samples exhibited non-Newtonian shear-thinning behavior, the flow behavior index (n) was less than 0.5 indicating strong pseudoplasticity, the consistency index (K) decreased sequentially from TBG, GG, to XG, and there was a significant difference between yield stress and concentration (P < 0.05). The hysteresis loop area (∆S) decreases sequentially from NLRS, BJ, to DIW, and the activation energy ( E a {E}_{{rm{a}}} ) decreases significantly with the increase in concentration (P < 0.05). This study has a reference value for improving the holding rate of sticky meals.
摘要粘度特性是影响助餐器保持率的重要因素。采用旋转粘度计和水浴法分别研究了黄原胶(XG)、瓜尔胶(GG)和刺豆胶(TBG)在去离子水、浆果汁(BJ)和坚果藕淀粉(NLRS)中的剪切流变性、触变性和糊化性能。结果表明:所有试样均表现出非牛顿剪切减薄行为，流动行为指数(n)小于0.5，表明具有较强的伪塑性，一致性指数(K)从TBG、GG到XG依次减小，屈服应力和浓度之间存在显著差异(P < 0.05)。迟滞回路面积(∆S)从NLRS、BJ到DIW依次减小，活化能(E a {E}_{{rm{a}}})随浓度的增加显著降低(P < 0.05)。本研究对提高粘性食物的保持率有一定的参考价值。
{"title":"Rheological thixotropy and pasting properties of food thickening gums orienting at improving food holding rate","authors":"Yu-Dong Fan, Lixun Zhang, Xing-cui Wang, Keyi Wang, Lan Wang, Zhenhan Wang, Feng Xue, Jinghui Zhu, Chao Wang","doi":"10.1515/arh-2022-0127","DOIUrl":"https://doi.org/10.1515/arh-2022-0127","url":null,"abstract":"Abstract The viscosity characteristic is an important factor affecting the holding rate of the meal-assisting instrument. The effects of shear rheological properties, thixotropy, and pasting properties of xanthan gum (XG), guar gum (GG), and thorn bean gum (TBG) in deionized water, berry juice (BJ), and nut lotus root starch (NLRS) were investigated using a rotational viscometer and a water bath, respectively. The results indicated that all samples exhibited non-Newtonian shear-thinning behavior, the flow behavior index (n) was less than 0.5 indicating strong pseudoplasticity, the consistency index (K) decreased sequentially from TBG, GG, to XG, and there was a significant difference between yield stress and concentration (P < 0.05). The hysteresis loop area (∆S) decreases sequentially from NLRS, BJ, to DIW, and the activation energy ( E a {E}_{{rm{a}}} ) decreases significantly with the increase in concentration (P < 0.05). This study has a reference value for improving the holding rate of sticky meals.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"32 1","pages":"100 - 121"},"PeriodicalIF":1.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42889166","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}
T. Tan, Yanlin Zhao, Xun Zhao, L. Chang, Sheng Ren
Abstract Study of mechanical properties of rock under hydro-mechanical coupling. The MTS815 rock mechanics system is used to perform triaxial compression tests of water-saturated sandstones under different confining pressures and pore water pressures. The results show that the peak deviation stress and its corresponding axial strain, residual deviation stress, initial deviation stress of dilation and deformation modulus of water-saturated sandstone are related to pore water pressure and confining pressure. They decrease with the increase of pore water pressure and increase with the increase of confining pressure. Poisson’s ratio and angle of rupture of water-saturated sandstone increase with pore water pressure. Based on the effective stress principle and Mohr–Coulomb criterion, the effective cohesion and effective residual cohesion of sandstone are 11.49 and 3.13 MPa, respectively, and the effective angle of internal friction and effective residual angle of internal friction are 38.32° and 25.32°, respectively. In addition, according to the variation relationship of sandstone strength, the relative strength criterion of sandstone under hydro-mechanical coupling is established.
{"title":"Mechanical properties of sandstone under hydro-mechanical coupling","authors":"T. Tan, Yanlin Zhao, Xun Zhao, L. Chang, Sheng Ren","doi":"10.1515/arh-2022-0120","DOIUrl":"https://doi.org/10.1515/arh-2022-0120","url":null,"abstract":"Abstract Study of mechanical properties of rock under hydro-mechanical coupling. The MTS815 rock mechanics system is used to perform triaxial compression tests of water-saturated sandstones under different confining pressures and pore water pressures. The results show that the peak deviation stress and its corresponding axial strain, residual deviation stress, initial deviation stress of dilation and deformation modulus of water-saturated sandstone are related to pore water pressure and confining pressure. They decrease with the increase of pore water pressure and increase with the increase of confining pressure. Poisson’s ratio and angle of rupture of water-saturated sandstone increase with pore water pressure. Based on the effective stress principle and Mohr–Coulomb criterion, the effective cohesion and effective residual cohesion of sandstone are 11.49 and 3.13 MPa, respectively, and the effective angle of internal friction and effective residual angle of internal friction are 38.32° and 25.32°, respectively. In addition, according to the variation relationship of sandstone strength, the relative strength criterion of sandstone under hydro-mechanical coupling is established.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"32 1","pages":"8 - 21"},"PeriodicalIF":1.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44235803","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 There are a large number of natural gas shows in the Upper Paleozoic of the central Hunan Basin. However, the hydrocarbon accumulation process was complicated due to the strong tectonic reformation in this area. A study of the natural gas accumulation period is of significance for determining gas accumulation models. In this research, the fluid inclusion samples were tested, the fluid inclusion occurrence characteristics, uniform temperature data, and reservoir evolution were analyzed, and four diagenetic periods and four diagenetic periods and three hydrocarbon accumulation periods were identified. (i) For the syntaxial stage, the filling is dark and nonluminous, and the fluid captured by the overgrowing cement around the particles is mainly seawater; (ii) for the (Early) Mesogenetic burial stage, the calcite cement grows around the particles or micritic calcite matrix, and the fluid captured is mainly brine; (iii) for (Late) Mesogenetic burial stage, two sets of decomposed fissures developed in massive calcite colloids with non-luminous gas-rich hydrocarbon inclusions within the crystals; and (iv) for Telogenetic burial stage, weakly fluorescent pure gaseous hydrocarbon inclusions are developed in luminescent calcite veins. The result indicates that the organic inclusions in the Lower Carboniferous of the central Hunan Basin are dominated by weakly fluorescent and nonfluorescent rich gas inclusions and pure gas-phase inclusions, with three stages of hydrocarbon filling. By integrating the average homogenization temperatures on burial curves, the three charging orders correspond to 260–250 Ma during the Late Permian, 249–245 Ma during the Early Triassic, and 208–170 Ma during the Late Triassic. Dense reservoir characteristics reveal deep basin gas reservoir in deep basin.
{"title":"Determining the gas accumulation period using fluid inclusion observations: Xiang Zhong Basin, China","authors":"Wei Zhu, Yongdi Qi, Shixin Dai, Mingsu Shen","doi":"10.1515/arh-2022-0126","DOIUrl":"https://doi.org/10.1515/arh-2022-0126","url":null,"abstract":"Abstract There are a large number of natural gas shows in the Upper Paleozoic of the central Hunan Basin. However, the hydrocarbon accumulation process was complicated due to the strong tectonic reformation in this area. A study of the natural gas accumulation period is of significance for determining gas accumulation models. In this research, the fluid inclusion samples were tested, the fluid inclusion occurrence characteristics, uniform temperature data, and reservoir evolution were analyzed, and four diagenetic periods and four diagenetic periods and three hydrocarbon accumulation periods were identified. (i) For the syntaxial stage, the filling is dark and nonluminous, and the fluid captured by the overgrowing cement around the particles is mainly seawater; (ii) for the (Early) Mesogenetic burial stage, the calcite cement grows around the particles or micritic calcite matrix, and the fluid captured is mainly brine; (iii) for (Late) Mesogenetic burial stage, two sets of decomposed fissures developed in massive calcite colloids with non-luminous gas-rich hydrocarbon inclusions within the crystals; and (iv) for Telogenetic burial stage, weakly fluorescent pure gaseous hydrocarbon inclusions are developed in luminescent calcite veins. The result indicates that the organic inclusions in the Lower Carboniferous of the central Hunan Basin are dominated by weakly fluorescent and nonfluorescent rich gas inclusions and pure gas-phase inclusions, with three stages of hydrocarbon filling. By integrating the average homogenization temperatures on burial curves, the three charging orders correspond to 260–250 Ma during the Late Permian, 249–245 Ma during the Early Triassic, and 208–170 Ma during the Late Triassic. Dense reservoir characteristics reveal deep basin gas reservoir in deep basin.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"32 1","pages":"83 - 99"},"PeriodicalIF":1.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42628538","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 Landslides caused countless economic and casualty losses in China, especially in mountainous and hilly areas. Landslide susceptibility mapping is an important approach and tool for landslide disaster prevention and control. This study presents a landslide susceptibility assessment using frequency ratio (FR) and index of entropy (IOE) models within a geographical information system for She County in the mountainous region of South Anhui, China. First, the landslide locations were ascertained in the study area using historical landslide records, aerial photographs, and multiple field surveys. In all, 502 landslides were identified and randomly divided into two groups as training (70%) and validation (30%) datasets. Additionally, the landslide-influencing factors, including slope angle, slope aspect, curvature, landform, lithology, distance to faults, distance to roads, distance to rivers, rainfall, and normalized difference vegetation index, were selected and their relative importance and weights were determined by FR and IOE models. The results show that the very high and high susceptibility classes cover nearly 50% of the study area. Finally, the comprehensive performance of the two models was validated and compared using receiver operating characteristic curves. The results demonstrated that the IOE model with the area under the curve (AUC) of 0.802, which is slightly better in prediction than the FR model (AUC = 0.786). The interpretation of the susceptibility map indicated that landform, slope degree, and distance to rivers plays a major role in landslide occurrence and distribution. The research results can be used for preliminary land use planning and hazard mitigation purposes.
{"title":"GIS-based landslide susceptibility mapping using frequency ratio and index of entropy models for She County of Anhui Province, China","authors":"Yu Liu, A. Yuan, Zhigang Bai, Jingzhong Zhu","doi":"10.1515/arh-2022-0122","DOIUrl":"https://doi.org/10.1515/arh-2022-0122","url":null,"abstract":"Abstract Landslides caused countless economic and casualty losses in China, especially in mountainous and hilly areas. Landslide susceptibility mapping is an important approach and tool for landslide disaster prevention and control. This study presents a landslide susceptibility assessment using frequency ratio (FR) and index of entropy (IOE) models within a geographical information system for She County in the mountainous region of South Anhui, China. First, the landslide locations were ascertained in the study area using historical landslide records, aerial photographs, and multiple field surveys. In all, 502 landslides were identified and randomly divided into two groups as training (70%) and validation (30%) datasets. Additionally, the landslide-influencing factors, including slope angle, slope aspect, curvature, landform, lithology, distance to faults, distance to roads, distance to rivers, rainfall, and normalized difference vegetation index, were selected and their relative importance and weights were determined by FR and IOE models. The results show that the very high and high susceptibility classes cover nearly 50% of the study area. Finally, the comprehensive performance of the two models was validated and compared using receiver operating characteristic curves. The results demonstrated that the IOE model with the area under the curve (AUC) of 0.802, which is slightly better in prediction than the FR model (AUC = 0.786). The interpretation of the susceptibility map indicated that landform, slope degree, and distance to rivers plays a major role in landslide occurrence and distribution. The research results can be used for preliminary land use planning and hazard mitigation purposes.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"32 1","pages":"22 - 33"},"PeriodicalIF":1.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42405526","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 aim of this work is to investigate the structural features, physicochemical, rheological, and emulsifying properties of pectin extracted from pumpkin “Cucurbita maxima” pulp and peel. After the peel and pulp of fresh pumpkin were solubilized in water at high temperature (80°C) and clarification, the obtained filtrate was treated with aluminum sulphate, which precipitates a fibrous coagulum. The results found that the major functional groups of pectin isolates identified by Fourier transform infrared are: –OH, CH2, C═C, –C–O–C–, and CH3. The results obtained using nuclear magnetic resonance methods suggest that these polysaccharides consist of two domains: the first one is homogalacturonan and the second is formed by rhamnogalacturonan. Mineral and metal ions on pectin surface detected using scanning electron microscopy coupled to energy dispersive X-ray analysis were different pulp and peel pectin. Rheological behavior of these biopolymers is suitably represented by the Herschel–Bulkley and power law models. The extracted pectin has a viscosity spectrum expressed by the following properties: G′, G′′, G*, and ∣ η ̇ ∣ ( ω ) | dot{eta }| (omega ) which, respectively, have the following values: 0.28–57.63, 0.15–34.38, 0.39–67.12, and 1.82–831.08 Pa s. These macromolecules have a negative charge on their surface. Rheological properties and emulsifying activity are significantly influenced by the structural composition and physicochemical properties. Graphical abstract
{"title":"Structure of pumpkin pectin and its effect on its technological properties","authors":"Baississe Salima, Dridi Seloua, Fahloul Djamel, Mezdour Samir","doi":"10.1515/arh-2022-0124","DOIUrl":"https://doi.org/10.1515/arh-2022-0124","url":null,"abstract":"Abstract The aim of this work is to investigate the structural features, physicochemical, rheological, and emulsifying properties of pectin extracted from pumpkin “Cucurbita maxima” pulp and peel. After the peel and pulp of fresh pumpkin were solubilized in water at high temperature (80°C) and clarification, the obtained filtrate was treated with aluminum sulphate, which precipitates a fibrous coagulum. The results found that the major functional groups of pectin isolates identified by Fourier transform infrared are: –OH, CH2, C═C, –C–O–C–, and CH3. The results obtained using nuclear magnetic resonance methods suggest that these polysaccharides consist of two domains: the first one is homogalacturonan and the second is formed by rhamnogalacturonan. Mineral and metal ions on pectin surface detected using scanning electron microscopy coupled to energy dispersive X-ray analysis were different pulp and peel pectin. Rheological behavior of these biopolymers is suitably represented by the Herschel–Bulkley and power law models. The extracted pectin has a viscosity spectrum expressed by the following properties: G′, G′′, G*, and ∣ η ̇ ∣ ( ω ) | dot{eta }| (omega ) which, respectively, have the following values: 0.28–57.63, 0.15–34.38, 0.39–67.12, and 1.82–831.08 Pa s. These macromolecules have a negative charge on their surface. Rheological properties and emulsifying activity are significantly influenced by the structural composition and physicochemical properties. Graphical abstract","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"32 1","pages":"34 - 55"},"PeriodicalIF":1.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41771658","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 To better study the shear characteristics of infilled joints with soil having different moisture contents, the influence of the moisture content on the shear characteristics of the infilled joint was explored in this paper, and a revised shear strength model of infilled joint surface is proposed. The results show that the shear dilatation modes of joints can be divided into four types: pure shear dilatation, pure shear compression, shear dilation-shear compression and shear compression-shear dilation. As the joint roughness coefficient (JRC) value increases, the normal displacement of the joint surface gradually increases during the shearing process and the normal stress has an inhibitory effect on dilatation. The infill material will weaken the peak shear stress of the joint surface. When the JRC value of joint surface is small, the weakening effect of soil with moisture content of 30% on peak shear stress is obvious. The revised joint roughness coefficient-joint wall compressive strength (JRC-JCS) model of infilled joint is proposed and the maximum shear stress value calculated by the model has a good linear relationship with the test value.
{"title":"Direct Shear Test and Shear Strength Model of Clay-Filled Joints","authors":"L. Chang, Yanlin Zhao, Yixian Wang, T. Tan","doi":"10.1515/arh-2020-0119","DOIUrl":"https://doi.org/10.1515/arh-2020-0119","url":null,"abstract":"Abstract To better study the shear characteristics of infilled joints with soil having different moisture contents, the influence of the moisture content on the shear characteristics of the infilled joint was explored in this paper, and a revised shear strength model of infilled joint surface is proposed. The results show that the shear dilatation modes of joints can be divided into four types: pure shear dilatation, pure shear compression, shear dilation-shear compression and shear compression-shear dilation. As the joint roughness coefficient (JRC) value increases, the normal displacement of the joint surface gradually increases during the shearing process and the normal stress has an inhibitory effect on dilatation. The infill material will weaken the peak shear stress of the joint surface. When the JRC value of joint surface is small, the weakening effect of soil with moisture content of 30% on peak shear stress is obvious. The revised joint roughness coefficient-joint wall compressive strength (JRC-JCS) model of infilled joint is proposed and the maximum shear stress value calculated by the model has a good linear relationship with the test value.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"31 1","pages":"50 - 62"},"PeriodicalIF":1.8,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41862606","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 flow characteristics of angel O/W emulsion, which is a yield stress fluid, was investigated. The hysteresis loop test was conducted for the strain below the slip yield point, and the single relaxation Maxwell model was used to fit the experimental data. Using these methods, the shear-rate dependence, stress dependence, and time dependence of the viscoelastic properties of the sample were evaluated in the region below the slip yield point. The shear-rate dependence induced by the stress-ramp rate and the stress dependence from the maximum applied stress influence the viscoelastic characteristics below the slip yield point in terms of the flow history. However, the time dependence of the viscoelastic characteristics could not be confirmed for any creep time. The yield stress measured in the stress-ramp test increases with the stress-ramp rate owing to the contribution of the viscous strain from the flow history.
{"title":"Flow and Yield Characteristics of Yield Stress Fluids Using Hysteresis Loop Test Below Slip Yield Point","authors":"Yasunori Sato, Y. Sugihara, Tsutomu Takahashi","doi":"10.1515/arh-2020-0115","DOIUrl":"https://doi.org/10.1515/arh-2020-0115","url":null,"abstract":"Abstract The flow characteristics of angel O/W emulsion, which is a yield stress fluid, was investigated. The hysteresis loop test was conducted for the strain below the slip yield point, and the single relaxation Maxwell model was used to fit the experimental data. Using these methods, the shear-rate dependence, stress dependence, and time dependence of the viscoelastic properties of the sample were evaluated in the region below the slip yield point. The shear-rate dependence induced by the stress-ramp rate and the stress dependence from the maximum applied stress influence the viscoelastic characteristics below the slip yield point in terms of the flow history. However, the time dependence of the viscoelastic characteristics could not be confirmed for any creep time. The yield stress measured in the stress-ramp test increases with the stress-ramp rate owing to the contribution of the viscous strain from the flow history.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"31 1","pages":"10 - 23"},"PeriodicalIF":1.8,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/arh-2020-0115","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46277795","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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