An attempt has been made to improve the paste stabilities both in viscosity of a hot starch paste and in phase of a starch-polyvinyl alcohol blend paste for warp sizing. The phase stability was evaluated in terms of t...An attempt has been made to improve the paste stabilities both in viscosity of a hot starch paste and in phase of a starch-polyvinyl alcohol blend paste for warp sizing. The phase stability was evaluated in terms of the initial demixing time, and the volume percentage of polyvinyl alcohol separated. It was found that starch cross-linking is harmful to the phase stability of a starch-polyvinyl alcohol blend paste no matter what a type of polyvinyl alcohol is used, although the cross-linking is an effective technique for stabilizing the viscosity of a hot starch paste. The separation rate and extent all increase with the increase in the cross-linking degree of starch. However, this defect can be eliminated through introducing quaternary ammonium groups into crosslinked starch molecules. Evident effect can be achieved when the degree of substitution is as less as 0.021. Generally, increase in the DS reduces the separation rate and extent, and thereby raising the phase stability. Moreover, the effects of both starch content and PVA type on the separation are also considered. Cationization after starch cross-linking shows improved stabilities both in viscosity and phase.展开更多
The main objective of this study was to determine the consolidation behaviour of clay slurries.A finegrained clay with high consistency limits(W_L = 180%,w_P= 120%) was investigated using conventional oedometer and be...The main objective of this study was to determine the consolidation behaviour of clay slurries.A finegrained clay with high consistency limits(W_L = 180%,w_P= 120%) was investigated using conventional oedometer and bench-top centrifuge tests.Results indicated that the slurry had an apparent preconsolidation(due to initial conditions,electrochemical interactions,tortuous drainage,and thixotropic strength) from e = 5.7 to e = 5.5 followed by virgin compression.Likewise,the low hydraulic conductivity(10^(-10)-10^(-12) m/s) was due to low porosity(small pore throats) and high tortuosity(long flow paths).Unlike consolidation of soils,the c_v and m_v decreased with increasing σ' but increased with increasing e and k.The data from the two tests correlated well in the range of σ' = 10-65 kPa,e = 5.5-3.86,k= 1.7 × 10^(-10)-5×10^(-11) m/s,F_c = 1-40 MN.New equations were developed to correlate the consolidation parameters(e,σ',k) with F_c.The deviation of k beyond 40 MN(e = 4.65) was due to deviation from the initial straight line portion of the settlement curve in the centrifuge test.展开更多
Samples of hot break tomato paste were collected from commercially produced aseptic totes after 6-11 months of storage at ambient temperature. Serum viscosity of the hot break tomato paste samples was analyzed at each...Samples of hot break tomato paste were collected from commercially produced aseptic totes after 6-11 months of storage at ambient temperature. Serum viscosity of the hot break tomato paste samples was analyzed at each sampling time and compared to the initial serum viscosity measured at the time of tomato paste manufacturing. As storage time increased, the serum viscosity of hot break tomato paste significantly decreased. After 7 months of storage, 16%-27% reduction of serum viscosity was observed in the hot break tomato paste. To evaluate effects of a heating on the serum viscosity of hot break tomato paste, the paste samples were reconstituted with water to 10° Brix, similar level of tomato solids in typical tomato sauce products. Diluted tomato paste was heated and held at 95℃ for 3 minutes and its serum viscosity was measured. After the heating, the serum viscosity of hot break tomato paste was slightly increased up to 5% of initial value, however the recovery was not significant (p 〈 0.05).展开更多
Objective To evaluate imaging features of the serous cystadenomas and mucinous cystic tumors of the pancreas. Methods The imaging findings in 59 patients with pathologically proven serous cystadenomas (SCs), mucinous ...Objective To evaluate imaging features of the serous cystadenomas and mucinous cystic tumors of the pancreas. Methods The imaging findings in 59 patients with pathologically proven serous cystadenomas (SCs), mucinous cystadenomas (MCs), and mucinous cystadenocarcinomas (MCCs) of the pancreas were reviewed for location, thickness of septa or the cyst wall, number of cysts, diameter of the largest cyst, lesion calcification, presence of mural node or solid enhancing component, dilatation of the main pancreatic duct (MPD), lesion communication with MPD, invasion of surrounding organs, and regional lymphadenopathy.Results The characteristic imaging feature of SCs was that of microcystic lesion with >6 cysts, the diameter of the largest cyst being <2 cm. Mucinous cystic tumors (MCTs) including MCs and MCCs were that of macrocystic lesion with <6 cysts, the diameter of the largest cyst being >2 cm. MCs was that of a lesion with smooth and regular cyst wall and septa, the wall/septa thickness being <0.3 cm. MCCs was that of a cystic lesion with thick irregular septa, presence of mural node or solid enhancing component, invasion of surrounding structures. These findings were of statistical significance. Conclusion SCs, MCs, and MCCs have characteristic imaging features. Analysis of the number of cysts, septation features, mural node or solid enhancing component, diameter of the largest cyst, dilatation of the pancreatic duct, and invasion of surrounding structures often can successfully subtype tumors into benign SCs or potentially malignant MCs or malignant MCCs.展开更多
Using the self-developed viscosity measuring device, the viscosity variations of coal-oil slurries with temperature increasing during coal-oil co-processing were studied. The results show that the viscosity of coal-oi...Using the self-developed viscosity measuring device, the viscosity variations of coal-oil slurries with temperature increasing during coal-oil co-processing were studied. The results show that the viscosity of coal-oil slurries prepared by different kinds of oil varies differently during heating. The viscosity of the coal-oil slurry prepared by the catalytic cracking slurry (FCC) generally decreases during heating. However, the viscosity of the coal-oil slurry prepared by the high-temperature coal tar (CT) will peak at 338 ℃ during heating. The differences in viscosity variations of coal-oil slurries are analyzed. In addition to the temperature, the properties of the solvents and coal are the main influencing factors. Because the used coal contains a large number of polar functional groups, the swelling behavior of the coal in polar solvent (CT) is stronger than that in non-polar solvent (FCC). The swelling effect of the coal can result in the appearance of the viscosity peak. Therefore, before 100 ~C, the solvent molecules entering into the coal pores is the main influencing factor of coal-oil slurries viscosity variations. After 100 ℃, the increasing of particle size of coal particles is the main influencing factor of coal-oil slurries viscosity variations.展开更多
The influences of carboxymethyl starch used as stabilizer upon the stability of native cornstarchpolyvinyl alcohol blend pastes for warp sizing have been investigated. The effect of the modified starch on the paste st...The influences of carboxymethyl starch used as stabilizer upon the stability of native cornstarchpolyvinyl alcohol blend pastes for warp sizing have been investigated. The effect of the modified starch on the paste stability was evaluated in terms of the initial demixing time and the volume percentage of separated starch. The carboxymethyl starch with a series of different degrees of substitution was prepared in ethanol dispersion by varying the amount of monochloroacetic acid reacted with refined native cornstarch. The paste stability strongly depends on the modification extent and amount of carboxymethyl starch used, and on native starch content in the paste. Increase in the modification extent and/or the amount of the modified starch effectively retards the phase separation and reduces the separation extent of native cornstarch-polyvinyl alcohol blend pastes.Moreover, the mechanism and favorable modification extent of carboxymethyl starch for enhancing paste stability are also investigated and discussed.展开更多
Granitic continental crust distinguishes the Earth from other planets in the Solar System. Consequently, for understanding terrestrial continent development, it is of great significance to investigate the formation an...Granitic continental crust distinguishes the Earth from other planets in the Solar System. Consequently, for understanding terrestrial continent development, it is of great significance to investigate the formation and evolution of granite.Crystal fractionation is one of principal magma evolution mechanisms. Nevertheless, it is controversial whether crystal fractionation can effectively proceed in felsic magma systems because of the high viscosity and non-Newtonian behavior associated with granitic magmas. In this paper, we focus on the physical processes and evaluate the role of crystal fractionation in the evolution of granitic magmas during non-transport processes, i.e., in magma chambers and after emplacement. Based on physical calculations and analyses, we suggest that general mineral particles can settle only at tiny speed(~10^(-9)–10^(-7) m s^(-1))in a granitic magma body due to high viscosity of the magma; however, the cumulating can be interrupted with convection in magma chambers, and the components of magma chambers will tend to be homogeneous. Magma convection ceases once the magma chamber develops into a mush(crystallinity, F>~40–50%). The interstitial melts can be extracted by hindered settling and compaction, accumulating gradually and forming a highly silicic melt layer. The high silica melts can further evolve into high-silica granite or high-silica rhyolite. At various crystallinities, multiple rejuvenation of the mush and the following magma intrusion may generate a granite complex with various components. While one special type of granites, represented by the South China lithium-and fluoride-rich granite, has lower viscosity and solidus relative to general granitic magmas, and may form vertical zonation in mineral-assemblage and composition through crystal fractionation. Similar fabrics in general intrusions that show various components on small lengthscales are not the result of gravitational settling. Rather, the flowage differentiation may play a key role. In general, granitic magma can undergo effective crystal fractionation; high-silica granite and volcanics with highly fractionated characteristics may be the products of crystal fractionation of felsic magmas, and many granitoids may be cumulates.展开更多
Under repeated train-induced loads, cement and emulsified asphalt mortar(CA mortar) as a viscoelastic material has a time-dependent deformation, part of which is irreversible. This could lead to debonding between the ...Under repeated train-induced loads, cement and emulsified asphalt mortar(CA mortar) as a viscoelastic material has a time-dependent deformation, part of which is irreversible. This could lead to debonding between the mortar layer and the track slab. Based on the theory of viscoelasticity and the analytical method of the time hardening law(THL), the viscoelastic deformation behavior of CA mortar was studied. Using ABAQUS, we established a solid model of China railway track system(CRTS) Ⅰ prefabricated slab track, with CA mortar at different initial Young’s moduli under cyclic loading corresponding to the influence of actual train loads. The results reveal that the fitted parameters of the THL for CA mortar are suitable for describing its viscoelastic deformation. As the initial Young’s modulus increases, the strain difference before and after cyclic loading gradually decreases, and the displacement difference increases from 0.2 mm to 0.6 mm. The deformation mainly occurs at the end of a mortar layer with longitudinal distribution of about 2.5 times the fasteners’ spacing. It follows that the viscoelastic performance of CA mortar is one of the most important reasons that cause debonding underneath the track slab. Therefore, we suggest that the adverse effects of viscoelastic behavior of CA mortar should be considered when researching such deformation and damage.展开更多
文摘An attempt has been made to improve the paste stabilities both in viscosity of a hot starch paste and in phase of a starch-polyvinyl alcohol blend paste for warp sizing. The phase stability was evaluated in terms of the initial demixing time, and the volume percentage of polyvinyl alcohol separated. It was found that starch cross-linking is harmful to the phase stability of a starch-polyvinyl alcohol blend paste no matter what a type of polyvinyl alcohol is used, although the cross-linking is an effective technique for stabilizing the viscosity of a hot starch paste. The separation rate and extent all increase with the increase in the cross-linking degree of starch. However, this defect can be eliminated through introducing quaternary ammonium groups into crosslinked starch molecules. Evident effect can be achieved when the degree of substitution is as less as 0.021. Generally, increase in the DS reduces the separation rate and extent, and thereby raising the phase stability. Moreover, the effects of both starch content and PVA type on the separation are also considered. Cationization after starch cross-linking shows improved stabilities both in viscosity and phase.
基金the University of Regina for providing laboratory space and the Natural Science and Engineering Research Council of Canada for financial assistance
文摘The main objective of this study was to determine the consolidation behaviour of clay slurries.A finegrained clay with high consistency limits(W_L = 180%,w_P= 120%) was investigated using conventional oedometer and bench-top centrifuge tests.Results indicated that the slurry had an apparent preconsolidation(due to initial conditions,electrochemical interactions,tortuous drainage,and thixotropic strength) from e = 5.7 to e = 5.5 followed by virgin compression.Likewise,the low hydraulic conductivity(10^(-10)-10^(-12) m/s) was due to low porosity(small pore throats) and high tortuosity(long flow paths).Unlike consolidation of soils,the c_v and m_v decreased with increasing σ' but increased with increasing e and k.The data from the two tests correlated well in the range of σ' = 10-65 kPa,e = 5.5-3.86,k= 1.7 × 10^(-10)-5×10^(-11) m/s,F_c = 1-40 MN.New equations were developed to correlate the consolidation parameters(e,σ',k) with F_c.The deviation of k beyond 40 MN(e = 4.65) was due to deviation from the initial straight line portion of the settlement curve in the centrifuge test.
文摘Samples of hot break tomato paste were collected from commercially produced aseptic totes after 6-11 months of storage at ambient temperature. Serum viscosity of the hot break tomato paste samples was analyzed at each sampling time and compared to the initial serum viscosity measured at the time of tomato paste manufacturing. As storage time increased, the serum viscosity of hot break tomato paste significantly decreased. After 7 months of storage, 16%-27% reduction of serum viscosity was observed in the hot break tomato paste. To evaluate effects of a heating on the serum viscosity of hot break tomato paste, the paste samples were reconstituted with water to 10° Brix, similar level of tomato solids in typical tomato sauce products. Diluted tomato paste was heated and held at 95℃ for 3 minutes and its serum viscosity was measured. After the heating, the serum viscosity of hot break tomato paste was slightly increased up to 5% of initial value, however the recovery was not significant (p 〈 0.05).
文摘Objective To evaluate imaging features of the serous cystadenomas and mucinous cystic tumors of the pancreas. Methods The imaging findings in 59 patients with pathologically proven serous cystadenomas (SCs), mucinous cystadenomas (MCs), and mucinous cystadenocarcinomas (MCCs) of the pancreas were reviewed for location, thickness of septa or the cyst wall, number of cysts, diameter of the largest cyst, lesion calcification, presence of mural node or solid enhancing component, dilatation of the main pancreatic duct (MPD), lesion communication with MPD, invasion of surrounding organs, and regional lymphadenopathy.Results The characteristic imaging feature of SCs was that of microcystic lesion with >6 cysts, the diameter of the largest cyst being <2 cm. Mucinous cystic tumors (MCTs) including MCs and MCCs were that of macrocystic lesion with <6 cysts, the diameter of the largest cyst being >2 cm. MCs was that of a lesion with smooth and regular cyst wall and septa, the wall/septa thickness being <0.3 cm. MCCs was that of a cystic lesion with thick irregular septa, presence of mural node or solid enhancing component, invasion of surrounding structures. These findings were of statistical significance. Conclusion SCs, MCs, and MCCs have characteristic imaging features. Analysis of the number of cysts, septation features, mural node or solid enhancing component, diameter of the largest cyst, dilatation of the pancreatic duct, and invasion of surrounding structures often can successfully subtype tumors into benign SCs or potentially malignant MCs or malignant MCCs.
文摘Using the self-developed viscosity measuring device, the viscosity variations of coal-oil slurries with temperature increasing during coal-oil co-processing were studied. The results show that the viscosity of coal-oil slurries prepared by different kinds of oil varies differently during heating. The viscosity of the coal-oil slurry prepared by the catalytic cracking slurry (FCC) generally decreases during heating. However, the viscosity of the coal-oil slurry prepared by the high-temperature coal tar (CT) will peak at 338 ℃ during heating. The differences in viscosity variations of coal-oil slurries are analyzed. In addition to the temperature, the properties of the solvents and coal are the main influencing factors. Because the used coal contains a large number of polar functional groups, the swelling behavior of the coal in polar solvent (CT) is stronger than that in non-polar solvent (FCC). The swelling effect of the coal can result in the appearance of the viscosity peak. Therefore, before 100 ~C, the solvent molecules entering into the coal pores is the main influencing factor of coal-oil slurries viscosity variations. After 100 ℃, the increasing of particle size of coal particles is the main influencing factor of coal-oil slurries viscosity variations.
基金It was financially supported by Science Research Foundation of Southern Yangtze University
文摘The influences of carboxymethyl starch used as stabilizer upon the stability of native cornstarchpolyvinyl alcohol blend pastes for warp sizing have been investigated. The effect of the modified starch on the paste stability was evaluated in terms of the initial demixing time and the volume percentage of separated starch. The carboxymethyl starch with a series of different degrees of substitution was prepared in ethanol dispersion by varying the amount of monochloroacetic acid reacted with refined native cornstarch. The paste stability strongly depends on the modification extent and amount of carboxymethyl starch used, and on native starch content in the paste. Increase in the modification extent and/or the amount of the modified starch effectively retards the phase separation and reduces the separation extent of native cornstarch-polyvinyl alcohol blend pastes.Moreover, the mechanism and favorable modification extent of carboxymethyl starch for enhancing paste stability are also investigated and discussed.
基金supported by the National Key R&D Program of China (Grant Nos. 2016YFC0600204 & 2016YFC0600408)the National Natural Science Foundation of China (Grant Nos. 41421062 & 41372005)
文摘Granitic continental crust distinguishes the Earth from other planets in the Solar System. Consequently, for understanding terrestrial continent development, it is of great significance to investigate the formation and evolution of granite.Crystal fractionation is one of principal magma evolution mechanisms. Nevertheless, it is controversial whether crystal fractionation can effectively proceed in felsic magma systems because of the high viscosity and non-Newtonian behavior associated with granitic magmas. In this paper, we focus on the physical processes and evaluate the role of crystal fractionation in the evolution of granitic magmas during non-transport processes, i.e., in magma chambers and after emplacement. Based on physical calculations and analyses, we suggest that general mineral particles can settle only at tiny speed(~10^(-9)–10^(-7) m s^(-1))in a granitic magma body due to high viscosity of the magma; however, the cumulating can be interrupted with convection in magma chambers, and the components of magma chambers will tend to be homogeneous. Magma convection ceases once the magma chamber develops into a mush(crystallinity, F>~40–50%). The interstitial melts can be extracted by hindered settling and compaction, accumulating gradually and forming a highly silicic melt layer. The high silica melts can further evolve into high-silica granite or high-silica rhyolite. At various crystallinities, multiple rejuvenation of the mush and the following magma intrusion may generate a granite complex with various components. While one special type of granites, represented by the South China lithium-and fluoride-rich granite, has lower viscosity and solidus relative to general granitic magmas, and may form vertical zonation in mineral-assemblage and composition through crystal fractionation. Similar fabrics in general intrusions that show various components on small lengthscales are not the result of gravitational settling. Rather, the flowage differentiation may play a key role. In general, granitic magma can undergo effective crystal fractionation; high-silica granite and volcanics with highly fractionated characteristics may be the products of crystal fractionation of felsic magmas, and many granitoids may be cumulates.
基金Project supported by the National Natural Science Foundation of China(No.51578472)。
文摘Under repeated train-induced loads, cement and emulsified asphalt mortar(CA mortar) as a viscoelastic material has a time-dependent deformation, part of which is irreversible. This could lead to debonding between the mortar layer and the track slab. Based on the theory of viscoelasticity and the analytical method of the time hardening law(THL), the viscoelastic deformation behavior of CA mortar was studied. Using ABAQUS, we established a solid model of China railway track system(CRTS) Ⅰ prefabricated slab track, with CA mortar at different initial Young’s moduli under cyclic loading corresponding to the influence of actual train loads. The results reveal that the fitted parameters of the THL for CA mortar are suitable for describing its viscoelastic deformation. As the initial Young’s modulus increases, the strain difference before and after cyclic loading gradually decreases, and the displacement difference increases from 0.2 mm to 0.6 mm. The deformation mainly occurs at the end of a mortar layer with longitudinal distribution of about 2.5 times the fasteners’ spacing. It follows that the viscoelastic performance of CA mortar is one of the most important reasons that cause debonding underneath the track slab. Therefore, we suggest that the adverse effects of viscoelastic behavior of CA mortar should be considered when researching such deformation and damage.