Abstract A theoretical model, the phase-field matching theory, has been used to investigate the localized states, their associated states, the local vibrational density of states, the coherent conductance, and the associated thermal conductivity of the perturbed ultra-thin film quasi-dimensional crystalline lattice. The defect disrupts the system’s translational symmetry in the perpendicular direction to it, which is axis Ox, and induces a localized state in its behavior that is not present in the bulk, scattering the incident elastic wave. The model was analyzed for three different cases of elastic parameters: softening, homogeneous, and hardening. The purpose is to investigate how the local dynamics can respond to changes in the microscopic environment in the perturbed domain. The analysis of the total phononic conductance spectra and the local vibrational densities states identifies distinguishing characteristics and demonstrates the sensor’s potential use in nondestroyed control.
{"title":"Vibrational wave scattering in disordered ultra-thin film with integrated nanostructures","authors":"Sansabilla Bouchareb, R. Tigrine, S. Fetah","doi":"10.1515/arh-2022-0135","DOIUrl":"https://doi.org/10.1515/arh-2022-0135","url":null,"abstract":"Abstract A theoretical model, the phase-field matching theory, has been used to investigate the localized states, their associated states, the local vibrational density of states, the coherent conductance, and the associated thermal conductivity of the perturbed ultra-thin film quasi-dimensional crystalline lattice. The defect disrupts the system’s translational symmetry in the perpendicular direction to it, which is axis Ox, and induces a localized state in its behavior that is not present in the bulk, scattering the incident elastic wave. The model was analyzed for three different cases of elastic parameters: softening, homogeneous, and hardening. The purpose is to investigate how the local dynamics can respond to changes in the microscopic environment in the perturbed domain. The analysis of the total phononic conductance spectra and the local vibrational densities states identifies distinguishing characteristics and demonstrates the sensor’s potential use in nondestroyed control.","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":"49215299","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 Seismological investigations are of a particular importance for the behavior of engineering structures and other structures of interest for the society under earthquake effects. This refers not only to the location of the structures themselves but also to their wider surrounding. In this context, it is important to determine the speed of seismic waves to define the possible location for the construction of secondary seismic stations. Also, determination of the speed of the seismic waves is very important to determine the compactness of the rock, where the seismic equipment is placed to increase the efficiency of monitoring the seismic activity.
{"title":"Determination of the velocity of seismic waves for the location of seismic station of Zatriq, Kosovo","authors":"Nazmi Hasi, Latif Hasi, N. Syla","doi":"10.1515/arh-2022-0136","DOIUrl":"https://doi.org/10.1515/arh-2022-0136","url":null,"abstract":"Abstract Seismological investigations are of a particular importance for the behavior of engineering structures and other structures of interest for the society under earthquake effects. This refers not only to the location of the structures themselves but also to their wider surrounding. In this context, it is important to determine the speed of seismic waves to define the possible location for the construction of secondary seismic stations. Also, determination of the speed of the seismic waves is very important to determine the compactness of the rock, where the seismic equipment is placed to increase the efficiency of monitoring the seismic activity.","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":"43550123","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 further explore the large deformation control technology of high ground stress soft rock tunnel, this study takes the highly weathered carbonaceous shale section of Muzhailing tunnel as the research background, the large deformation control effect of scheme 1 “three-step method” and scheme 2 “pilot tunnel expansion method” are compared and analysed by field test and numerical simulation. The results show that the numerical simulation results are consistent with the field test, and the deformation trend of the tunnel is the same. The maximum deformation of the tunnel occurs at the middle step. From the perspective of tunnel deformation, control effect is reduced by about 10% compared with scheme 1, and the deformation of both schemes does not exceed the reserved deformation (400 mm). From the perspective of construction efficiency, the construction efficiency of scheme 2 is 23.07% lower than that of scheme 1. Taking into account the deformation control effect and construction efficiency, it is recommended that the three-step method should be adopted in the construction of this section, and the research results can provide a reference for the construction of the carbonaceous slate section of the tunnel.
{"title":"Research on large deformation control technology of highly weathered carbonaceous slate tunnel","authors":"G. Cui, Qinlong Chen","doi":"10.1515/arh-2022-0152","DOIUrl":"https://doi.org/10.1515/arh-2022-0152","url":null,"abstract":"Abstract In order to further explore the large deformation control technology of high ground stress soft rock tunnel, this study takes the highly weathered carbonaceous shale section of Muzhailing tunnel as the research background, the large deformation control effect of scheme 1 “three-step method” and scheme 2 “pilot tunnel expansion method” are compared and analysed by field test and numerical simulation. The results show that the numerical simulation results are consistent with the field test, and the deformation trend of the tunnel is the same. The maximum deformation of the tunnel occurs at the middle step. From the perspective of tunnel deformation, control effect is reduced by about 10% compared with scheme 1, and the deformation of both schemes does not exceed the reserved deformation (400 mm). From the perspective of construction efficiency, the construction efficiency of scheme 2 is 23.07% lower than that of scheme 1. Taking into account the deformation control effect and construction efficiency, it is recommended that the three-step method should be adopted in the construction of this section, and the research results can provide a reference for the construction of the carbonaceous slate section of the tunnel.","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":"47027175","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}
Youqiang Qiu, Yijun Wang, Yang Liu, Liujun Zhang, Yashao Chen, Chenyang Li, Tong Wu, Chaoxiang Wang
Abstract In order to prepare high-performance foaming agent for field-cast foamed lightweight soil, the fiber compound foaming agent was prepared by the combination of anionic surfactant sodium dodecyl sulfate (SDS) and nonionic surfactant alkyl polyglucoside (APG), supplemented by hydrolyzed polyacryamide (HPAM) as the foam stabilizer. The effects of the mass ratio of surfactant and the content of foam stabilizer on the properties of fiber compound foaming agent were compared and analyzed by testing the surface tension, viscosity, foam volume, and foam half-life. Based on the analysis of foam volume and foam stability of foaming agent, the optimal mass ratio of surfactant and the optimal content of foam stabilizer were optimized. In addition, based on the optimized fiber compound foaming agent to prepare foamed lightweight soil, the influence of different foaming agent concentrations on the application performance of foamed lightweight soil was studied, and the appropriate concentration of fiber compound foaming agent solution was further optimized. Thus, the optimum reaction conditions for preparing SDS-APG compound foaming agent containing foam stabilizer HPAM were proposed as follows: mass ratio of SDS to APG was 2:1, concentration of HPAM was 3.75 wt‰, and concentration of foaming agent was 9.21 wt%.
{"title":"Development of fiber compound foaming agent and experimental study on application performance of foamed lightweight soil","authors":"Youqiang Qiu, Yijun Wang, Yang Liu, Liujun Zhang, Yashao Chen, Chenyang Li, Tong Wu, Chaoxiang Wang","doi":"10.1515/arh-2023-0108","DOIUrl":"https://doi.org/10.1515/arh-2023-0108","url":null,"abstract":"Abstract In order to prepare high-performance foaming agent for field-cast foamed lightweight soil, the fiber compound foaming agent was prepared by the combination of anionic surfactant sodium dodecyl sulfate (SDS) and nonionic surfactant alkyl polyglucoside (APG), supplemented by hydrolyzed polyacryamide (HPAM) as the foam stabilizer. The effects of the mass ratio of surfactant and the content of foam stabilizer on the properties of fiber compound foaming agent were compared and analyzed by testing the surface tension, viscosity, foam volume, and foam half-life. Based on the analysis of foam volume and foam stability of foaming agent, the optimal mass ratio of surfactant and the optimal content of foam stabilizer were optimized. In addition, based on the optimized fiber compound foaming agent to prepare foamed lightweight soil, the influence of different foaming agent concentrations on the application performance of foamed lightweight soil was studied, and the appropriate concentration of fiber compound foaming agent solution was further optimized. Thus, the optimum reaction conditions for preparing SDS-APG compound foaming agent containing foam stabilizer HPAM were proposed as follows: mass ratio of SDS to APG was 2:1, concentration of HPAM was 3.75 wt‰, and concentration of foaming agent was 9.21 wt%.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"106 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":"136306020","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, Duygu Sen Baykal, G. Kilic, G. Susoy, H. Zakaly, A. Ene, H. Tekin
Abstract We report some fundamental gamma-ray shielding properties and individual transmission factors (TFs) of five distinct glass samples with a nominal composition of xSb2O3·(40 − x)PbO·60B2O3·0.5CuO and (where; 0 ≤ x ≤ 40 mol%). Phy-X/PSD and MCNPX (version 2.7.0) Monte Carlo code are utilized to determine several critical parameters, such as cross-sections, attenuation coefficients, half and tenth value layers, build-up factors, and TFs. A general transmission setup is designed using basic requirements. Accordingly, TFs are evaluated for several medical radioisotopes. Next, the gamma-ray shielding parameters and TFs are assessed together in terms of providing the validity of the findings. Our results showed that there is a positive contribution of increasing Sb2O3 amount in the glass matrix owing its direct effect to the density increment as well. This positive effect on gamma-ray shielding properties is also observed for decreasing mean free path values from S1 to S5 samples. The exposure build-up factor (EBF) and energy absorption build-up factor (EABF) values, increasing the quantity of Sb2O3 supplementation, resulted in a general reduction in EBF and EABF values (i.e., from 0.5 to 40 mfp). When the quantity of Sb2O3 rises from S1 to S5, the collision rate of incoming gamma rays in glass samples increases significantly. The TF figures reveal that S5 showed the least transmission behavior across all the above-mentioned studied glass thicknesses. It can be concluded that increasing the Sb2O3 additive is a beneficial and monotonic technique, when the gamma-ray shielding qualities or TF values must be further enhanced.
{"title":"Assessment of the usability conditions of Sb2O3–PbO–B2O3 glasses for shielding purposes in some medical radioisotope and a wide gamma-ray energy spectrum","authors":"G. Almisned, Duygu Sen Baykal, G. Kilic, G. Susoy, H. Zakaly, A. Ene, H. Tekin","doi":"10.1515/arh-2022-0133","DOIUrl":"https://doi.org/10.1515/arh-2022-0133","url":null,"abstract":"Abstract We report some fundamental gamma-ray shielding properties and individual transmission factors (TFs) of five distinct glass samples with a nominal composition of xSb2O3·(40 − x)PbO·60B2O3·0.5CuO and (where; 0 ≤ x ≤ 40 mol%). Phy-X/PSD and MCNPX (version 2.7.0) Monte Carlo code are utilized to determine several critical parameters, such as cross-sections, attenuation coefficients, half and tenth value layers, build-up factors, and TFs. A general transmission setup is designed using basic requirements. Accordingly, TFs are evaluated for several medical radioisotopes. Next, the gamma-ray shielding parameters and TFs are assessed together in terms of providing the validity of the findings. Our results showed that there is a positive contribution of increasing Sb2O3 amount in the glass matrix owing its direct effect to the density increment as well. This positive effect on gamma-ray shielding properties is also observed for decreasing mean free path values from S1 to S5 samples. The exposure build-up factor (EBF) and energy absorption build-up factor (EABF) values, increasing the quantity of Sb2O3 supplementation, resulted in a general reduction in EBF and EABF values (i.e., from 0.5 to 40 mfp). When the quantity of Sb2O3 rises from S1 to S5, the collision rate of incoming gamma rays in glass samples increases significantly. The TF figures reveal that S5 showed the least transmission behavior across all the above-mentioned studied glass thicknesses. It can be concluded that increasing the Sb2O3 additive is a beneficial and monotonic technique, when the gamma-ray shielding qualities or TF values must be further enhanced.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"32 1","pages":"178 - 189"},"PeriodicalIF":1.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45176117","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 purpose of this article is to evaluate four different gas turbine cogeneration cycles which are basic, absorption cooling, air heating and air fuel heating cogeneration cycles by using the most important six evaluation criteria for different excess air coefficient, different compression rates, and different compressor inlet air temperatures. These six evaluation criteria are electrical heat ratio, exergy efficiency, incremental heat rate, artificial thermal efficiency, fuel energy saving ratio, and specific fuel consumption. It is seen that the air-fuel heating cogeneration cycle is the most efficient among the cycles examined for a certain compressor compression ratio, followed by the air heating, basic, and absorption cooling cycles.
{"title":"Evaluation of four different cogeneration cycles by using some criteria","authors":"Rabi Karaali̇, Arzu Keven","doi":"10.1515/arh-2022-0128","DOIUrl":"https://doi.org/10.1515/arh-2022-0128","url":null,"abstract":"Abstract The purpose of this article is to evaluate four different gas turbine cogeneration cycles which are basic, absorption cooling, air heating and air fuel heating cogeneration cycles by using the most important six evaluation criteria for different excess air coefficient, different compression rates, and different compressor inlet air temperatures. These six evaluation criteria are electrical heat ratio, exergy efficiency, incremental heat rate, artificial thermal efficiency, fuel energy saving ratio, and specific fuel consumption. It is seen that the air-fuel heating cogeneration cycle is the most efficient among the cycles examined for a certain compressor compression ratio, followed by the air heating, basic, and absorption cooling cycles.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"32 1","pages":"122 - 137"},"PeriodicalIF":1.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44739523","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 During processing and bubble growth processes, the melt viscosity changes with temperature, pressure, and blowing agent concentration. Therefore, measurement and prediction methods for viscosity characterization in terms of temperature, pressure, and blowing agent dependency are needed. This study demonstrates the applicability of in-line viscosity measurements during the foam injection molding process and a model for viscosity superposition and prediction. In the present study, polystyrene and a modified polylactide for foaming applications with nitrogen as blowing agent are investigated. By changing the injection speed, temperature, and blowing agent concentration, the process conditions are varied, and thus the resulting pressure drops within the in-line measurement die. The calculated shear rates and viscosities are shifted to a master curve by the application of superposition principles. The viscosity dependency on temperature is described by the Arrhenius equation, the pressure by the Barus equation, and for the blowing agent concentration, a novel Barus-like equation was derived and applied. The prediction of the master curve viscosity function was achieved by the power-law model in combination with the superposition principles and showed good agreement with the shifted in-line data. Finally, the in-line measurements and viscosity predictions are validated by comparing them to rotational and capillary rheometer measurements.
{"title":"In-line measurement and modeling of temperature, pressure, and blowing agent dependent viscosity of polymer melts","authors":"T. Schaible, C. Bonten","doi":"10.1515/arh-2022-0123","DOIUrl":"https://doi.org/10.1515/arh-2022-0123","url":null,"abstract":"Abstract During processing and bubble growth processes, the melt viscosity changes with temperature, pressure, and blowing agent concentration. Therefore, measurement and prediction methods for viscosity characterization in terms of temperature, pressure, and blowing agent dependency are needed. This study demonstrates the applicability of in-line viscosity measurements during the foam injection molding process and a model for viscosity superposition and prediction. In the present study, polystyrene and a modified polylactide for foaming applications with nitrogen as blowing agent are investigated. By changing the injection speed, temperature, and blowing agent concentration, the process conditions are varied, and thus the resulting pressure drops within the in-line measurement die. The calculated shear rates and viscosities are shifted to a master curve by the application of superposition principles. The viscosity dependency on temperature is described by the Arrhenius equation, the pressure by the Barus equation, and for the blowing agent concentration, a novel Barus-like equation was derived and applied. The prediction of the master curve viscosity function was achieved by the power-law model in combination with the superposition principles and showed good agreement with the shifted in-line data. Finally, the in-line measurements and viscosity predictions are validated by comparing them to rotational and capillary rheometer measurements.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"32 1","pages":"69 - 82"},"PeriodicalIF":1.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45861636","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, Duygu Sen Baykal, G. Susoy, G. Kilic, H. Zakaly, A. Ene, H. Tekin
Abstract The aim of this study is to assess the individual gamma-ray transmission factors (TFs) and some fundamental gamma-ray attenuation properties of several types of glasses based on WO3–TeO2–B2O3 glasses system. MCNPX (version 2.7.0) is used for the calculation of TFs. Other critical parameters are determined using the Phy-X/PSD program. To determine the TFs of studied glasses, several medical radioisotopes are determined along with their characteristic gamma-ray energies. The superior values for the investigated parameters are found in glass sample S6. Furthermore, the exposure build-up factor and energy absorption build-up factor values for glass sample S6 were the lowest. S6 glass sample with the chemical composition 0.03833B + 0.26075O + 0.11591Zn + 0.52783Te + 0.05718W and a density of 3.3579 g/cm3 is found to have exceptional gamma-ray attenuation qualities, according to our findings. It can be concluded that the prospective attributes of WO3-doped glass systems and associated glass compositions would be beneficial for scientific community in terms of providing a clearer view for some advanced applications of these glass types.
{"title":"Determination of gamma-ray transmission factors of WO3–TeO2–B2O3 glasses using MCNPX Monte Carlo code for shielding and protection purposes","authors":"G. Almisned, Duygu Sen Baykal, G. Susoy, G. Kilic, H. Zakaly, A. Ene, H. Tekin","doi":"10.1515/arh-2022-0132","DOIUrl":"https://doi.org/10.1515/arh-2022-0132","url":null,"abstract":"Abstract The aim of this study is to assess the individual gamma-ray transmission factors (TFs) and some fundamental gamma-ray attenuation properties of several types of glasses based on WO3–TeO2–B2O3 glasses system. MCNPX (version 2.7.0) is used for the calculation of TFs. Other critical parameters are determined using the Phy-X/PSD program. To determine the TFs of studied glasses, several medical radioisotopes are determined along with their characteristic gamma-ray energies. The superior values for the investigated parameters are found in glass sample S6. Furthermore, the exposure build-up factor and energy absorption build-up factor values for glass sample S6 were the lowest. S6 glass sample with the chemical composition 0.03833B + 0.26075O + 0.11591Zn + 0.52783Te + 0.05718W and a density of 3.3579 g/cm3 is found to have exceptional gamma-ray attenuation qualities, according to our findings. It can be concluded that the prospective attributes of WO3-doped glass systems and associated glass compositions would be beneficial for scientific community in terms of providing a clearer view for some advanced applications of these glass types.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"32 1","pages":"166 - 177"},"PeriodicalIF":1.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48445676","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 This work corresponds to a study on using a cellulose-based water-retaining agent, hydroxypropyl methylcellulose (HPMC), in phosphogypsum (PG)-stabilized mortars. The results in cementitious pastes showed that when PG replaced cement, there was a reduction in the fluidity of the mixture (by 64.32%) and a drastic increase in the flow stress (from 1.8 to 614.0 Pa) due to its greater need for water, proving to be porous. However, when PG was combined with the hydration stabilizing admixture (HSA) and HPMC, greater fluidity, lower yield stress, and lower viscosity were obtained. In addition, PG contributed to the delay in setting times. In the stabilized mortars, the use of HPMC ceased the phenomenon of water exudation, and the additions of 0.15 and 0.20% provided the highest compressive strengths to the 48 h mortars (±5.28 and 5.28 MPa, respectively). On the other hand, the increase in HSA content to 1.2% at 72 h stabilization caused losses in mechanical performance and modulus of elasticity. Still, when comparing the compressive strength of the 48 h mortar with PG vs mortar with cement, there is a 71.13% increase in strength.
{"title":"Effect of phosphogypsum and water-retaining in the stabilization and durability of stabilized mortars","authors":"Alessandra Zaleski, J. Rocha","doi":"10.1515/arh-2022-0130","DOIUrl":"https://doi.org/10.1515/arh-2022-0130","url":null,"abstract":"Abstract This work corresponds to a study on using a cellulose-based water-retaining agent, hydroxypropyl methylcellulose (HPMC), in phosphogypsum (PG)-stabilized mortars. The results in cementitious pastes showed that when PG replaced cement, there was a reduction in the fluidity of the mixture (by 64.32%) and a drastic increase in the flow stress (from 1.8 to 614.0 Pa) due to its greater need for water, proving to be porous. However, when PG was combined with the hydration stabilizing admixture (HSA) and HPMC, greater fluidity, lower yield stress, and lower viscosity were obtained. In addition, PG contributed to the delay in setting times. In the stabilized mortars, the use of HPMC ceased the phenomenon of water exudation, and the additions of 0.15 and 0.20% provided the highest compressive strengths to the 48 h mortars (±5.28 and 5.28 MPa, respectively). On the other hand, the increase in HSA content to 1.2% at 72 h stabilization caused losses in mechanical performance and modulus of elasticity. Still, when comparing the compressive strength of the 48 h mortar with PG vs mortar with cement, there is a 71.13% increase in strength.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"32 1","pages":"138 - 154"},"PeriodicalIF":1.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48621984","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}
Daniel Van Opdenbosch, Martin Kretschmer, O. Lieleg, C. Zollfrank
Abstract The viscosities of poly(3-hydroxybutyrate) (PHB) with mixed tacticities were determined as functions of temperature and shearing rate via plate–plate viscosimetry, and fitted by a combined Herschel–Bulkley–Cross–Doolittle model while applying Carvalho et al.’s single-point correction. They were compared to values of slit viscosimetry, obtained during processing at a temperature of 428 K. In both cases, measured values and fitted model parameters as a function of tacticity exhibited a discontinuous behaviour at a fraction of meso diads of 0.7. To further investigate, we calculated values of vibrational and excess free volume. We found that these correlate with structural and external properties, some of which were reported in earlier works, namely the paracrystalline contents and specific volumes of the materials at room temperature, as well as their energies of fracture during tensile testing. These, in turn, correlate with the statistical averages of relative lengths of chain segments of similar a- or iso-tacticity. Hence, we found that expressing changing tacticities simply by a continuous progression of the fraction of meso diads is insufficient to trace associated discontinuities of the flow behaviour in mixed-tacticity PHB. We conclude that free volume is generated by polymer chain conformational disorder, which should be treated on the oligomeric chain segment level.
{"title":"Free volumes in mixed-tacticity poly(3-hydroxybutyrate) determined by viscosimetry and their correlations with structural features and mechanical properties","authors":"Daniel Van Opdenbosch, Martin Kretschmer, O. Lieleg, C. Zollfrank","doi":"10.1515/arh-2022-0125","DOIUrl":"https://doi.org/10.1515/arh-2022-0125","url":null,"abstract":"Abstract The viscosities of poly(3-hydroxybutyrate) (PHB) with mixed tacticities were determined as functions of temperature and shearing rate via plate–plate viscosimetry, and fitted by a combined Herschel–Bulkley–Cross–Doolittle model while applying Carvalho et al.’s single-point correction. They were compared to values of slit viscosimetry, obtained during processing at a temperature of 428 K. In both cases, measured values and fitted model parameters as a function of tacticity exhibited a discontinuous behaviour at a fraction of meso diads of 0.7. To further investigate, we calculated values of vibrational and excess free volume. We found that these correlate with structural and external properties, some of which were reported in earlier works, namely the paracrystalline contents and specific volumes of the materials at room temperature, as well as their energies of fracture during tensile testing. These, in turn, correlate with the statistical averages of relative lengths of chain segments of similar a- or iso-tacticity. Hence, we found that expressing changing tacticities simply by a continuous progression of the fraction of meso diads is insufficient to trace associated discontinuities of the flow behaviour in mixed-tacticity PHB. We conclude that free volume is generated by polymer chain conformational disorder, which should be treated on the oligomeric chain segment level.","PeriodicalId":50738,"journal":{"name":"Applied Rheology","volume":"32 1","pages":"56 - 68"},"PeriodicalIF":1.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45397505","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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