The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
R A Massom - One of the best experts on this subject based on the ideXlab platform.
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antarctic ice shelf Disintegration triggered by sea ice loss and ocean swell
Nature, 2018Co-Authors: R A Massom, Ted Scambos, Luke G Bennetts, Phillip Reid, Vernon A Squire, Sharon StammerjohnAbstract:Understanding the causes of recent catastrophic ice shelf Disintegrations is a crucial step towards improving coupled models of the Antarctic Ice Sheet and predicting its future state and contribution to sea-level rise. An overlooked climate-related causal factor is regional sea ice loss. Here we show that for the Disintegration events observed (the collapse of the Larsen A and B and Wilkins ice shelves), the increased seasonal absence of a protective sea ice buffer enabled increased flexure of vulnerable outer ice shelf margins by ocean swells that probably weakened them to the point of calving. This outer-margin calving triggered wider-scale Disintegration of ice shelves compromised by multiple factors in preceding years, with key prerequisites being extensive flooding and outer-margin fracturing. Wave-induced flexure is particularly effective in outermost ice shelf regions thinned by bottom crevassing. Our analysis of satellite and ocean-wave data and modelling of combined ice shelf, sea ice and wave properties highlights the need for ice sheet models to account for sea ice and ocean waves.
Xiaoyu Tang - One of the best experts on this subject based on the ideXlab platform.
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evolution of the Disintegration breakage of red bed soft rock using a logistic regression model
Transportation geotechnics, 2020Co-Authors: Zongtang Zhang, Wenhua Gao, Chaofeng Zeng, Xiaoyu TangAbstract:Abstract The Disintegration of red-bed soft rock is closely associated with a series of geological disasters. However, research on the evolution of the Disintegration breakage has not yet been sufficiently executed. To compensate for this insufficiency, slake durability tests are carried out by three widely used experimental methods to explore the Disintegration of red-bed soft rock. Then, based on the logistic regression model, the evolution model of Disintegration breakage is derived, and the mathematical meaning of the model parameters (i.e., β 0 and β 1 ) is analysed. The results show that the variation in model parameters corresponds to the process of Disintegration breakage. Moreover, the new formulas based on the established evolution model to calculate the Disintegration index (including the slake durability index and the Disintegration ratio) are presented to replace the traditional expression. Finally, the effects of the test device, drying temperature, and Disintegration index on the Disintegration breakage of soft rock are studied and discussed. Compared with the slake durability index, the Disintegration ratio considering all mesh sizes is a more reasonable index to quantify the Disintegration characteristics. The results of the present study are helpful for understanding the evolutionary process of Disintegration breakage.
Zongtang Zhang - One of the best experts on this subject based on the ideXlab platform.
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effect of different test methods on the Disintegration behaviour of soft rock and the evolution model of Disintegration breakage under cyclic wetting and drying
Engineering Geology, 2020Co-Authors: Zongtang Zhang, Wenhua GaoAbstract:Abstract Red-bed soft rock covers a large area in China and is often used as filling materials for highway roadbed and embankment, while the Disintegration of red-bed soft rock often causes serious settlement of the roadbed and decreased stability. To thoroughly study the Disintegration properties of red-bed soft rock, a series of slake durability tests were performed using different test methods. First, the gradation of disintegrated red-bed soft rock was investigated, and the shape of the gradation curve mainly presented as reverse sigmoidal and hyperbolic. Moreover, the evolution model of the Disintegration breakage of red-bed soft rock using the Morgan-Mercer-Florin (MMF) model was derived, and the model parameters were analysed. Based on the test results, the Disintegration behaviours of red-bed soft rock were measured by the Disintegration ratio; then, the new formula to calculate the Disintegration ratio based on the concept of the traditional Disintegration ratio was derived using the established model. Finally, the effect of different test methods, i.e., different test devices, drying temperatures and sizes, on Disintegration breakage under cyclic wetting and drying was analysed, and the test results showed that the rate of Disintegration was accelerated by the slake durability apparatus, a higher drying temperature and a larger size.
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evolution of the Disintegration breakage of red bed soft rock using a logistic regression model
Transportation geotechnics, 2020Co-Authors: Zongtang Zhang, Wenhua Gao, Chaofeng Zeng, Xiaoyu TangAbstract:Abstract The Disintegration of red-bed soft rock is closely associated with a series of geological disasters. However, research on the evolution of the Disintegration breakage has not yet been sufficiently executed. To compensate for this insufficiency, slake durability tests are carried out by three widely used experimental methods to explore the Disintegration of red-bed soft rock. Then, based on the logistic regression model, the evolution model of Disintegration breakage is derived, and the mathematical meaning of the model parameters (i.e., β 0 and β 1 ) is analysed. The results show that the variation in model parameters corresponds to the process of Disintegration breakage. Moreover, the new formulas based on the established evolution model to calculate the Disintegration index (including the slake durability index and the Disintegration ratio) are presented to replace the traditional expression. Finally, the effects of the test device, drying temperature, and Disintegration index on the Disintegration breakage of soft rock are studied and discussed. Compared with the slake durability index, the Disintegration ratio considering all mesh sizes is a more reasonable index to quantify the Disintegration characteristics. The results of the present study are helpful for understanding the evolutionary process of Disintegration breakage.
Mary Ann Johnson - One of the best experts on this subject based on the ideXlab platform.
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The Effect of Inorganic Salt on Disintegration of Tablets with High Loading of Amorphous Solid Dispersion Containing Copovidone
Pharmaceutical Research, 2020Co-Authors: Jie Ren, Julie M. Novak, Eric Kemp, Gregory Johnson, Gerard Klinzing, Mary Ann JohnsonAbstract:Purpose While including amorphous solid dispersion (ASD) in tablet formulations is increasingly common, tablets containing high ASD loading are associated with slow Disintegration, which presents a challenge to control pill burden for less potent compounds. Methods We use a model ASD, composed of a hydrophobic drug with copovidone and a non-ionic surfactant, to explore formulation options that can prevent slow Disintegration. Results In addition to the ASD loading, the pH of the Disintegration medium and the inclusion of inorganic salts in the tablet also have an impact on the tablet Disintegration time. Certain kosmotropic salts, when added in the formulation, can significantly accelerate tablet Disintegration, though the rank order in their effectiveness does not exactly follow the Hofmeister series at pH 1.8. The particle size and dissolution rate of the salt can contribute to its overall effectiveness. Conclusion We provided a mechanistic explanation of the Disintegration process: fast-dissolving kosmotropic salt results in a concentrated salt solution inside the restrained tablet matrix, thus inhibiting the dissolution of copovidone and preventing polymer gelling which is the main cause leading the slow Disintegration. The outcome of this study has enabled the design of a higher ASD loading platform formulation for copovidone based ASD. Graphical Abstract MicroCT aids the mechanistic understanding of the role of inorganic salt in the tablet Disintegration of amorphous solid dispersion based formulation
Mansoor A. Khan - One of the best experts on this subject based on the ideXlab platform.
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Process Analytical Technology to Understand the Disintegration Behavior of Alendronate Sodium Tablets
Journal of pharmaceutical sciences, 2013Co-Authors: Abhay Gupta, Vilayat A. Sayeed, Mansoor A. KhanAbstract:ABSTRACT: Various adverse events including esophagus irritations have been reported with the use of alendronate tablets, likely attributed to the rapid tablet Disintegration in the mouth or esophagus. Accordingly, the Disintegration of six alendronate tablet drug products was studied using a newly developed testing device equipped with in-line sensors, in addition to the official compendial procedure for measuring the Disintegration time. The in-line sensors were used to monitor the particle count and solution pH change to assess the onset and duration of Disintegration. A relatively large variation was observed in the Disintegration time of the tested drug products using the compendial method. The data collected using the in-line sensors suggested that all tested drug products exhibited almost instantaneous onset of Disintegration, under 2 s, and a sharp drop in solution pH. The drop in pH was slower for tablets with slower Disintegration. The in-house prepared alendronate test tablets also showed similar trends suggesting rapid solubilization of the drug contributed to the fast tablet Disintegration. This research highlights the usefulness of the newly developed in-line analytical method in combination with the compendial method in providing a better understanding of the Disintegration and the accompanying drug solubilization processes for fast disintegrating tablet drug products.
