The Experts below are selected from a list of 180 Experts worldwide ranked by ideXlab platform
Shi Jian Yuan - One of the best experts on this subject based on the ideXlab platform.
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Effect of internal pressure on corner radius and thickness distribution of shear hydro-bending of 5A02 aluminum alloy tube
Transactions of Nonferrous Metals Society of China, 2012Co-Authors: Yong Wang, Shi Jian YuanAbstract:The effects of internal pressure on forming defects, corner radius and thickness distribution of 5A02 aluminum alloy shear hydro-bending tubes were studied by experiment. Numerical simulation was conducted to analyze the effect of internal pressure on axial strain and invariable lines of thickness strain. The ultra-small bending tubes were successfully manufactured when the relative internal pressure, ratio of internal pressure and yield stress of the material, is higher than 0.2. The relative bending radius of the first outer corner decreases from 0.3 to 0.025 when the relative internal pressure increases from 0.2 to 1.2. The axial thickness distribution is different in intrados and extrados. The changing rate of thickness is larger with a higher internal pressure. The minimum thickness decreases from 1.45 mm to 0.87 mm when the relative internal pressure changes from 0.2 to 1.2. The tube is divided into Feeding Zone, the first corner, shearing Zone, the second corner and holding Zone. The strain of Feeding Zone and the first corner is compressive caused by the Feeding. The strain of the second corner and holding Zone is tensile for far away from Feeding punches. The strain of shearing Zone changes from compressive to tensile with rising of internal pressure. On one hand, the smaller corner radius formed by higher internal pressure blocks the Feeding. On the other hand, the corner filling strengthens the extensive strain of shearing Zone. In the Feeding Zone and holding Zone, thickness strain is positive, and the tube thickens. In the corner and shear Zones, thickness strain is negative, and the tube thins.
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Warm hydroforming of magnesium alloy tube with large expansion ratio within non-uniform temperature field
Transactions of Nonferrous Metals Society of China, 2012Co-Authors: Wen-da Zhang, Zhu-bin He, Shi Jian YuanAbstract:According to warm hydroforming with poor thickness uniformity and low expansion ratio, a new approach named warm hydroforming with non-uniform temperature field was presented. Warm hydroforming die with nonuniform temperature field was designed and temperature field along tube axis was established with differential temperature gradient. Then, the effect of the temperature difference between the forming Zone and the Feeding Zone on thickness uniformity along the part axis was studied in a certain loading path. Thickening of the Feeding Zone decreases and the thickness uniformity of tubular part is improved by selecting appropriate temperature difference, for this experiment, suitable temperature difference is 150 °C. Further, the effect of the preform shape formed by warm hydroforming on the limit expansion ratio of magnesium alloy tube was studied, using preform with wrinkles and preform with expansion ratio of 35% hydroformed by using differential temperature. The limit expansion ratio reaches 66.2% by using the preform with expansion ratio of 35%.
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Effect of internal pressure on corner radius and thickness distribution of shear hydro-bending of 5A02 aluminum alloy tube
Transactions of Nonferrous Metals Society of China (English Edition), 2012Co-Authors: Yong Wang, Cong Han, Shi Jian YuanAbstract:The effects of internal pressure on forming defects, corner radius and thickness distribution of 5A02 aluminum alloy shear hydro-bending tubes were studied by experiment. Numerical simulation was conducted to analyze the effect of internal pressure on axial strain and invariable lines of thickness strain. The ultra-small bending tubes were successfully manufactured when the relative internal pressure, ratio of internal pressure and yield stress of the material, is higher than 0.2. The relative bending radius of the first outer corner decreases from 0.3 to 0.025 when the relative internal pressure increases from 0.2 to 1.2. The axial thickness distribution is different in intrados and extrados. The changing rate of thickness is larger with a higher internal pressure. The minimum thickness decreases from 1.45 mm to 0.87 mm when the relative internal pressure changes from 0.2 to 1.2. The tube is divided into Feeding Zone, the first corner, shearing Zone, the second corner and holding Zone. The strain of Feeding Zone and the first corner is compressive caused by the Feeding. The strain of the second corner and holding Zone is tensile for far away from Feeding punches. The strain of shearing Zone changes from compressive to tensile with rising of internal pressure. On one hand, the smaller corner radius formed by higher internal pressure blocks the Feeding. On the other hand, the corner filling strengthens the extensive strain of shearing Zone. In the Feeding Zone and holding Zone, thickness strain is positive, and the tube thickens. In the corner and shear Zones, thickness strain is negative, and the tube thins. ?? 2012 The Nonferrous Metals Society of China.
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Thickness Demarcation Circle of Double-Cone Tube during Hydroforming
Advanced Materials Research, 2011Co-Authors: Wen Jing Yuan, Hao Bin Tian, Xiaosong Wang, Shi Jian YuanAbstract:The analytic formula of the thickness demarcation circle during hydroforming of double-cone tube is derived by using the mechanical analysis and the total strain theory. The effect of friction coefficient, expansion coefficient, ratio of axial stress to internal pressure, length of Feeding Zone, and initial thickness of tube on the thickness distribution can be given by this formula quantitatively, and the analytic results were compared with the FEM analysis and experimental results. The results show that with the increasing of friction coefficient, the ratio of axial stress to internal pressure, the relative length of Feeding Zone, the distance between thickness demarcation circle and tube end decreased, that means the increasing of length of the thinning Zone, and with the increasing of relative thickness of tube blank, the distance between thickness demarcation circle and tube end increased, that means decreasing of length of the thinning Zone.
Agba D Salman - One of the best experts on this subject based on the ideXlab platform.
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roller compaction infrared thermography as a pat for monitoring powder flow from Feeding to compaction Zone
International Journal of Pharmaceutics, 2020Co-Authors: Mingzhe Yu, Chalak S Omar, Alexander Schmidt, J D Litster, Marcus Weidemann, Agba D SalmanAbstract:Abstract Roller compaction is a continuous dry granulation process, in which powder is compressed by two counter-rotating rollers. During this process, the powder Feeding to the compaction Zone has a significant effect on product quality. This work investigates the flow of powder from the Feeding Zone to the compaction Zone using online infrared thermography as Process Analytical Technology (PAT) which is achieved via a specially built cheek plate (side-sealing). The powder undergoes increasing stress from the rollers when it is approaching the minimum gap of the compaction Zone, which can be indirectly monitored by measuring the powder temperature. The online monitoring of the powder flow during the roller compaction helps locate the nip region and identify the effect of different roller forces on the temperature of the Feeding powder. The results show that the nip region can be identified by analysing the temperature profiles from the Feeding to the compaction Zone. The increase of roller force results in an increasing slope of the powder temperature profile. In addition, offline X-ray CT measurement results show the increase of density along the Feeding to the compaction direction, which is compared with Johanson theory under different roller forces in the roller compaction process.
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Application of Feeding guiders to improve the powder distribution in the two scales of roller compactors.
International Journal of Pharmaceutics, 2019Co-Authors: Mingzhe Yu, Chalak S Omar, Alexander Schmidt, J D Litster, Marcus Weidemann, Agba D SalmanAbstract:Abstract Roller compaction is a continuous dry granulation process, where the powder is compressed between two counter-rotating rollers and compacted into ribbons. The quality and homogeneity of the granulate is determined by the uniformity and porosity of the ribbon, which depends on the Feeding process of the primary powder to the rollers, the flow properties of the primary powder and process parameters such as roller forces. Previous work was conducted to improve the powder flow and distribution in the Feeding Zone by developing new Feeding guiders, which are located in the Feeding Zone close to the rollers on the lab-scale roller compactor Alexanderwerk WP120 Pharma (Yu et al., 2018). These new Feeding guiders were used to reduce the amount of powder that is delivered to the centre of the rollers and increase the amount of powder that is delivered to the sides of the rollers, in comparison to the original Feeding guiders. This modified concept using new Feeding guiders has been applied to the large-scale roller compactor Alexanderwerk WP200 Pharma in the present work. In order to evaluate the homogeneity of the ribbon properties across the ribbon width, the temperature profile and porosity distribution across the ribbon width were measured. The new Feeding guiders resulted in ribbons being produced with a more uniform temperature profile and porosity distribution across the ribbon width when using the small and large scale roller compactors at different process parameters.
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improving Feeding powder distribution to the compaction Zone in the roller compaction
European Journal of Pharmaceutics and Biopharmaceutics, 2018Co-Authors: Mingzhe Yu, Chalak S Omar, Alexander Schmidt, J D Litster, Agba D SalmanAbstract:Abstract In the roller compaction process, powder flow properties have a significant influence on the uniformity of the ribbon properties. The objective of this work was to improve the powder flow in the Feeding Zone by developing novel Feeding guiders which are located in the Feeding Zone close to the rollers in the roller compactor (side sealing system). Three novel Feeding guiders were designed by 3D printing and used in the roller compactor, aiming to control the amount of powder passing across the roller width. The new Feeding guiders were used to guide more powder to the sides between the rollers and less powder to the centre comparing to the original Feeding elements. Temperature profile and porosity across the ribbon width indicated the uniformity of the ribbon properties. Using the novel Feeding guiders resulted in producing ribbons with uniform temperature profile and porosity distribution across the ribbon width. The design of the Feeding guiders contributed to improving the tensile strength of the ribbons produced from the compaction stage as well as reducing the fines produced from the crushing stage.
Yong Wang - One of the best experts on this subject based on the ideXlab platform.
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Effect of internal pressure on corner radius and thickness distribution of shear hydro-bending of 5A02 aluminum alloy tube
Transactions of Nonferrous Metals Society of China, 2012Co-Authors: Yong Wang, Shi Jian YuanAbstract:The effects of internal pressure on forming defects, corner radius and thickness distribution of 5A02 aluminum alloy shear hydro-bending tubes were studied by experiment. Numerical simulation was conducted to analyze the effect of internal pressure on axial strain and invariable lines of thickness strain. The ultra-small bending tubes were successfully manufactured when the relative internal pressure, ratio of internal pressure and yield stress of the material, is higher than 0.2. The relative bending radius of the first outer corner decreases from 0.3 to 0.025 when the relative internal pressure increases from 0.2 to 1.2. The axial thickness distribution is different in intrados and extrados. The changing rate of thickness is larger with a higher internal pressure. The minimum thickness decreases from 1.45 mm to 0.87 mm when the relative internal pressure changes from 0.2 to 1.2. The tube is divided into Feeding Zone, the first corner, shearing Zone, the second corner and holding Zone. The strain of Feeding Zone and the first corner is compressive caused by the Feeding. The strain of the second corner and holding Zone is tensile for far away from Feeding punches. The strain of shearing Zone changes from compressive to tensile with rising of internal pressure. On one hand, the smaller corner radius formed by higher internal pressure blocks the Feeding. On the other hand, the corner filling strengthens the extensive strain of shearing Zone. In the Feeding Zone and holding Zone, thickness strain is positive, and the tube thickens. In the corner and shear Zones, thickness strain is negative, and the tube thins.
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Effect of internal pressure on corner radius and thickness distribution of shear hydro-bending of 5A02 aluminum alloy tube
Transactions of Nonferrous Metals Society of China (English Edition), 2012Co-Authors: Yong Wang, Cong Han, Shi Jian YuanAbstract:The effects of internal pressure on forming defects, corner radius and thickness distribution of 5A02 aluminum alloy shear hydro-bending tubes were studied by experiment. Numerical simulation was conducted to analyze the effect of internal pressure on axial strain and invariable lines of thickness strain. The ultra-small bending tubes were successfully manufactured when the relative internal pressure, ratio of internal pressure and yield stress of the material, is higher than 0.2. The relative bending radius of the first outer corner decreases from 0.3 to 0.025 when the relative internal pressure increases from 0.2 to 1.2. The axial thickness distribution is different in intrados and extrados. The changing rate of thickness is larger with a higher internal pressure. The minimum thickness decreases from 1.45 mm to 0.87 mm when the relative internal pressure changes from 0.2 to 1.2. The tube is divided into Feeding Zone, the first corner, shearing Zone, the second corner and holding Zone. The strain of Feeding Zone and the first corner is compressive caused by the Feeding. The strain of the second corner and holding Zone is tensile for far away from Feeding punches. The strain of shearing Zone changes from compressive to tensile with rising of internal pressure. On one hand, the smaller corner radius formed by higher internal pressure blocks the Feeding. On the other hand, the corner filling strengthens the extensive strain of shearing Zone. In the Feeding Zone and holding Zone, thickness strain is positive, and the tube thickens. In the corner and shear Zones, thickness strain is negative, and the tube thins. ?? 2012 The Nonferrous Metals Society of China.
K J Wang - One of the best experts on this subject based on the ideXlab platform.
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studies on positive conveying in helically channeled single screw extruders
Express Polymer Letters, 2012Co-Authors: K J WangAbstract:A solids conveying theory called double-flight driving theory was proposed for helically channeled single screw extruders. In the extruder, screw channel rotates against static barrel channel, which behaves as cooperative embedded twin-screws for the positive conveying. They turn as two parallel arc plates, between which an arc-plate solid-plug was assumed. By analyzing the forces on the solid-plug in the barrel channel and screw channel, the boundary conditions when the solid-plug is waived of being cut off on barrel wall, were found to have the capacity of the positive conveying. Experi- mental data were obtained using a specially designed extruder with a helically channeled barrel in the Feeding Zone and a pressure-adjustable die. The effects of the barrel channel geometry and friction coefficients on the conveying mechanism were presented and compared with the experimental results. The simulations showed that the positive conveying could be achieved after optimizing extruder designs. Compared with the traditional design with the friction-drag conveying, the throughput is higher while screw torque and energy consumption are decreased. Besides, the design criteria of the barrel channel were also discussed.
S I Ipatov - One of the best experts on this subject based on the ideXlab platform.
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probabilities of collisions of planetesimals from different regions of the Feeding Zone of the terrestrial planets with the forming planets and the moon
Solar System Research, 2019Co-Authors: S I IpatovAbstract:Migration of planetesimals from the Feeding Zone of the terrestrial planets, which was divided into seven regions depending on the distance to the Sun, was simulated. The influence of gravity of all planets was taken into account. In some cases, the embryos of the terrestrial planets rather than the planets themselves were considered; their masses were assumed to be 0.1 or 0.3 of the current masses of the planets. The arrays of orbital elements of migrated planetesimals were used to calculate the probabilities of their collisions with the planets, the Moon, or their embryos. Based on our calculations, we drew conclusions on the process of accumulation of the terrestrial planets. The embryos of the terrestrial planets, the masses of which did not exceed a tenth of the current planetary masses, accumulated planetesimals mainly from the vicinity of their orbits. When planetesimals fell onto the embryos of the terrestrial planets from the Feeding Zone of Jupiter and Saturn, these embryos had not yet acquired the current masses of the planets, and the material of this Zone (including water and volatiles) could be accumulated in the inner layers of the terrestrial planets. The inner layers of each of the terrestrial planets were mainly formed from the material located in the vicinity of the orbit of a certain planet. The outer layers of the Earth and Venus could accumulate the same material for these two planets from different parts of the Feeding Zone of the terrestrial planets. The Earth and Venus could acquire more than half of their masses in 5 Myr. A relatively rapid growth of the bulk of the Martian mass can be explained by the formation of Mars' embryo (the mass of which is several times less than that of Mars) due to contraction of a rarefied condensation.
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Probabilities of Collisions of Planetesimals from Different Regions of the Feeding Zone of the Terrestrial Planets with the Forming Planets and the Moon
Solar System Research, 2019Co-Authors: S I IpatovAbstract:Migration of planetesimals from the Feeding Zone of the terrestrial planets, which was divided into seven regions depending on the distance to the Sun, was simulated. The influence of gravity of all planets was taken into account. In some cases, the embryos of the terrestrial planets rather than the planets themselves were considered; their masses were assumed to be 0.1 or 0.3 of the current masses of the planets. The arrays of orbital elements of migrated planetesimals were used to calculate the probabilities of their collisions with the planets, the Moon, or their embryos. As distinct from the earlier modeling of the evolution of disks of the bodies coagulating in collisions, this approach makes it possible to calculate more accurately the probabilities of collisions of planetesimals with planetary embryos of different masses for some evolution stages. When studying the composition of planetary embryos formed from planetesimals, which initially were at different distances from the Sun, we considered the narrower Zones, from which planetesimals came, as compared to those examined earlier, and analyzed the temporal changes in the composition of planetary embryos rather than only the final composition of planets. Based on our calculations, we drew conclusions on the process of accumulation of the terrestrial planets. The embryos of the terrestrial planets, the masses of which did not exceed a tenth of the current planetary masses, accumulated planetesimals mainly from the vicinity of their orbits. When planetesimals fell onto the embryos of the terrestrial planets from the Feeding Zone of Jupiter and Saturn, these embryos had not yet acquired the current masses of the planets, and the material of this Zone (including water and volatiles) could be accumulated in the inner layers of the terrestrial planets and the Moon. For planetesimals which initially were at a distance of 0.7–0.9 AU from the Sun, the probabilities of their infall onto the embryos of the Earth and Venus, the mass of which is 0.3 of the present masses of the planets, differed less than twofold for these embryos. The total mass of planetesimals, which initially were in each part of the region between 0.7 and 1.5 AU from the Sun and collided with the almost-formed Earth and Venus, apparently differed by less than two times for these planets. The inner layers of each of the terrestrial planets were mainly formed from the material located in the vicinity of the orbit of a certain planet. The outer layers of the Earth and Venus could accumulate the same material for these two planets from different parts of the Feeding Zone of the terrestrial planets. The Earth and Venus could acquire more than half of their masses in 5 Myr. The material ejection that occurred in impacts of bodies with the planets, which was not taken into account in the model, may enlarge the accumulation time for the planets. A relatively rapid growth of the bulk of the Martian mass can be explained by the formation of Mars’ embryo (the mass of which is several times less than that of Mars) due to contraction of a rarified condensation. For the mass ratio of the Earth’s and lunar embryos equal to 81 (the same as that for the masses of the Earth and the Moon), the ratio of the probabilities for infalls of planetesimals onto the Earth’s and lunar embryos did not exceed 54 for the considered variants of calculations; and it was highest for the embryos’ masses approximately three times less than the present masses of these celestial bodies. Special features in the formation of the terrestrial planets can be explained even under a relatively gentle decrease of the semi-major axis of Jupiter’s orbit due to ejection of planetesimals by Jupiter into hyperbolic orbits. In this modeling, it is not necessary to consider the migration of Jupiter to the orbit of Mars and back, as in the Grand Tack model, and sharp changes in the orbits of the giant planets falling into a resonance, as in the Nice model.
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Delivery of Water and Volatiles to the Terrestrial Planets and the Moon
Solar System Research, 2018Co-Authors: M. Ya. Marov, S I IpatovAbstract:From modeling the evolution of disks of planetesimals under the influence of planets, it has been shown that the mass of water delivered to the Earth from beyond Jupiter’s orbit could be comparable to the mass of terrestrial oceans. A considerable portion of the water could have been delivered to the Earth’s embryo, when its mass was smaller than the current mass of the Earth. While the Earth’s embryo mass was growing to half the current mass of the Earth, the mass of water delivered to the embryo could be near 30% of the total amount of water delivered to the Earth from the Feeding Zone of Jupiter and Saturn. Water of the terrestrial oceans could be a result of mixing the water from several sources with higher and lower D/H ratios. The mass of water delivered to Venus from beyond Jupiter’s orbit was almost the same as that for the Earth, if normalized to unit mass of the planet. The analogous per-unit mass of water delivered to Mars was two−three times as much as that for the Earth. The mass of water delivered to the Moon from beyond Jupiter’s orbit could be less than that for the Earth by a factor not more than 20.
