The Experts below are selected from a list of 34359 Experts worldwide ranked by ideXlab platform
Lars J. Munkholm - One of the best experts on this subject based on the ideXlab platform.
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Clay Dispersibility and Soil Friability—Testing the Soil Clay-to-Carbon Saturation Concept
Vadose Zone Journal, 2012Co-Authors: Per Schjonning, Lars J. Munkholm, L W De Jonge, Per Moldrup, Bent T Christensen, Jorgen E OlesenAbstract:Soil organic carbon (OC) influences clay dispersibility, which affects soil tilth conditions and the risk of vertical migration of clay colloids. No universal lower threshold of OC has been identified for satisfactory stabilization of soil structure. We tested the concept of clay saturation with OC as a predictor of clay dispersibility and soil Friability. Soil was sampled three years in a field varying in clay content (~100 to ~220 g kg-1 soil) and grown with different crop rotations. Clay dispersibility was measured after end-over-end shaking of field-moist soil and 1-2 mm sized aggregates either air-dried or rewetted to -100 hPa matric potential. Tensile strength of 1-2, 2-4, 4-8 and 8-16 mm air-dried aggregates was calculated from their compressive strength, and soil Friability estimated from the strength-volume relation. Crop rotation characteristics gave only minor effects on clay dispersibility and no detectable effects on soil Friability. Dispersed clay correlated to soil content of clay but the correlation increased if subtracting a fraction assumed protected by OC. This trend was less convincing for soil tensile strength and Friability. Increased clay dispersibility and reduced soil Friability one year of measurements could be ascribed to wet conditions for potato harvest and tillage the preceding year. Literature data indicate soils’ content of clay and silt (Fines20) to be a better predictor of specific surface area than clay. We conclude that a clay/OC ratio of 10 and a Fines20/OC ratio of 20 may serve as corresponding thresholds for clay dispersibility, the latter probably best reflecting organomineral interactions of importance to the soil physical properties.
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clay dispersibility and soil Friability testing the soil clay to carbon saturation concept
Vadose Zone Journal, 2012Co-Authors: Per Schjonning, Lars J. Munkholm, L W De Jonge, Per Moldrup, Bent T Christensen, Jorgen E OlesenAbstract:Soil organic carbon (OC) influences clay dispersibility, which affects soil tilth conditions and the risk of vertical migration of clay colloids. No universal lower threshold of OC has been identified for satisfactory stabilization of soil structure. We tested the concept of clay saturation with OC as a predictor of clay dispersibility and soil Friability. Soil was sampled three years in a field varying in clay content (~100 to ~220 g kg-1 soil) and grown with different crop rotations. Clay dispersibility was measured after end-over-end shaking of field-moist soil and 1-2 mm sized aggregates either air-dried or rewetted to -100 hPa matric potential. Tensile strength of 1-2, 2-4, 4-8 and 8-16 mm air-dried aggregates was calculated from their compressive strength, and soil Friability estimated from the strength-volume relation. Crop rotation characteristics gave only minor effects on clay dispersibility and no detectable effects on soil Friability. Dispersed clay correlated to soil content of clay but the correlation increased if subtracting a fraction assumed protected by OC. This trend was less convincing for soil tensile strength and Friability. Increased clay dispersibility and reduced soil Friability one year of measurements could be ascribed to wet conditions for potato harvest and tillage the preceding year. Literature data indicate soils’ content of clay and silt (Fines20) to be a better predictor of specific surface area than clay. We conclude that a clay/OC ratio of 10 and a Fines20/OC ratio of 20 may serve as corresponding thresholds for clay dispersibility, the latter probably best reflecting organomineral interactions of importance to the soil physical properties.
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Soil Friability: A review of the concept, assessment and effects of soil properties and management
Geoderma, 2011Co-Authors: Lars J. MunkholmAbstract:Abstract This review gathers and synthesizes literature on soil Friability produced during the last three decades. Soil Friability is of vital importance for crop production and the impact of crop production on the environment. A friable soil is characterized by an ease of fragmentation of undesirably large aggregates/clods and a difficulty in fragmentation of minor aggregates into undesirable small elements. Soil Friability has been assessed using qualitative field methods as well as quantitative field and laboratory methods at different scales of observation. The qualitative field methods are broadly used by scientists, advisors and farmers, whereas the quantitative laboratory methods demand specialized skills and more or less sophisticated equipment. Most methods address only one aspect of soil Friability, i.e. either the strength of unconfined soil or the fragment size distribution after applying a stress. All methods have significant advantages and limitations. The use of a mixture of qualitative and quantitative methods to get a comprehensive and adequate assessment of soil Friability is recommended. Poor Friability can be experienced if soil is either too wet or too dry and there is a range in water contents for optimal Friability. There is a strong need to get more detailed knowledge about effects of soil water content on soil Friability and especially to be able to quantify the least limiting water range for soil Friability and therefore soil tillage. A strong relationship between organic matter and Friability has been found but it is not possible to identify a specific lower critical level of organic matter across soil types. Sustainable management of soil requires continuous and adequate inputs of organic matter to sustain or improve soil Friability. Intensive tillage and traffic in unfavorable conditions threatens soil Friability and may initiate a vicious cycle where increasingly higher intensity of tillage is needed to produce a proper seedbed.
Marc S. Gordon - One of the best experts on this subject based on the ideXlab platform.
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Process Considerations in Reducing Tablet Friability and Their Effect on in vitro Dissolution
Drug Development and Industrial Pharmacy, 1994Co-Authors: Marc S. GordonAbstract:AbstractThe tablet Friability resulting from manufacturing process variations was studied for two differently sized tablets using the same formulation. Granulations containing lower moisture contents required higher compression and ejection forces to manufacture a tablet at a given hardness, although this did not influence Friability. Increased tablet hardness (and to a lesser extent decreased tablet thickness) decreased the tablet Friability of the larger tablet. An increase in the quantity of granulating fluid increased the granulation particle size and slightly improved compactibility without significantly affecting Friability. Tablet dissolution increased as the quantity of granulating fluid was decreased. There was a strong interaction, with respect to dissolution, between moisture content and the amount of granulating fluid. Tablet hardness did not significantly influence dissolution. Doubling the quantity of magnesium stearate in the granulation in one tablet strength decreased the maximum tablet h...
Dingwei Wang - One of the best experts on this subject based on the ideXlab platform.
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Resilience and Friability of Transportation Networks: Evaluation, Analysis and Optimization
IEEE Systems Journal, 2011Co-Authors: W. H. Ip, Dingwei WangAbstract:To analyze the resilience of transportation networks, it is proposed to use a quantifiable resilience evaluation approach. First, we represent transportation networks by an undirected graph with the nodes as cities and edges as traffic roads. Because the survivability of transportation of a pair of cities depends on the number of passageways between them, the resilience of a city node can be evaluated by the weighted average number of reliable passageways with all other city nodes in the network. The network resilience can then be calculated by the weighted sum of the resilience of all nodes. To identify critical road lines or hub cities in networks, the concept of Friability is proposed. This is defined as the reduction in total resilience upon removing an edge or hub city. Following the resilience and Friability evaluation, a structure optimization model with a computational algorithm for transportation network design is recommended. Based on the recommended approaches, the resilience and Friability of the railway network within the Chinese mainland is evaluated and analyzed. Several interesting conclusions are drawn from the computational results. The Friability value of the railway lines in the Sichuan Basin which was damaged by the recent earthquake in China was also calculated.
Changquan Calvin Sun - One of the best experts on this subject based on the ideXlab platform.
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Dependence of Friability on Tablet Mechanical Properties and a Predictive Approach for Binary Mixtures
Pharmaceutical research, 2017Co-Authors: Shubhajit Paul, Changquan Calvin SunAbstract:Purpose To systematically assess the dependence of Friability on tablet mechanical properties, compaction pressure, and tablet porosity.
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Validation and applications of an expedited tablet Friability method.
International journal of pharmaceutics, 2015Co-Authors: Frederick Osei-yeboah, Changquan Calvin SunAbstract:The harmonized monograph on tablet Friability test in United States Pharmacopeia (USP), European Pharmacopeia (Pharm. Eur.), and Japanese Pharmacopeia (JP) is designed to assess adequacy of mechanical strength of a batch of tablets. Currently, its potential applications in formulation development have been limited due to the batch requirement that is both labor and material intensive. To this end, we have developed an expedited tablet Friability test method, using the existing USP test apparatus. The validity of the expedited Friability method is established by showing that the Friability data from the expedited method is not statistically different from those from the standard pharmacopeia method using materials of very different mechanical properties, i.e., microcrystalline cellulose and dibasic calcium phosphate dihydrate. Using the expedited Friability method, we have shown that the relationship between tablet Friability and tablet mechanical strength follows a power law expression. Furthermore, potential applications of this expedited Friability test in facilitating systematic and efficient tablet formulation and tooling design are demonstrated with examples.
Angi Nadya Bestari - One of the best experts on this subject based on the ideXlab platform.
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optimization formula tablet extract of bengkuang pachyrrhizus erosus variation avicel ph 101 and crospovidone
Current Opinion in Organ Transplantation, 2018Co-Authors: Rizki Kharisma, Ika Puspita Sari, Angi Nadya BestariAbstract:Bengkuang ( Pachyrrhizus erosus ) contains daidzein which is pro-estrogenic compound, suppressing bone restoration by directing mechanism in bone estrogen receptor. Bengkuang can be developed into a useful source of phytoestrogens as a supplement in menopausal women. This study aims to determine the stability and influence of Avicel® PH 101 and crospovidone on granular flow properties and physical properties of Bengkuang tuber extract. Bengkuang tuber extracts were made into tablet preparations by wet granulation method. Variation of crospovidone composition was between 2-5%, while Avicel® PH 101 was between 38.86 to 41.86%. The tablet formulation is optimized using the Simplex Lattice Design method. The results show that the addition of Avicel® PH 101 can improve the index of determination, water absorption, moisture content, hardness, time of disintegration, and Friability of the tablet, as well as crospovidone addition. Avicel® PH 101 and crospovidone interactions increase water content, decrease hardness, and tablet Friability. The optimum tablet formula consists of composition of 293 mg of Avicel® PH 101 and 14 mg of crospovidone per tablet. Testing of optimum formula results with SLD method did not differ significantly to the response of the compression index, hardness and Friability of the tablet. The tablet was stable at room temperature (30oC ± 2 oC) for four weeks.
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the formulation of pacing costus speciosus extract tablet by using avicel ph 200 as filler binder and amylum as disintegration agent
INDONESIAN JOURNAL OF PHARMACY, 2018Co-Authors: Damayanti Damayanti, Ika Puspita Sari, Angi Nadya Bestari, T Saifullah N Sulaiman, Irfan Muris SetiawanAbstract:Pacing ( Costus speciosus ) is an herbaceous plant that is native to Indonesia and it can be used as a male contraceptive due to spermatogenesis inhibition. The purpose of this study is to find out the composition of optimum Avicel PH 200 ® as the filler-binder and amylum as the disintegration agent and to find out the variations on physical properties of the powder and tablet. The tablets were made by directly compression in 8 runs based on Simplex Lattice Design (SLD) from Design Expert 7.1.5, in which the test on physical properties of powder includes tapping index, water absorption, and moisture content, as well as on the physical properties of tablet, including hardness, Friability, and disintegration time. The results showed that the variation in the composition between Avicel ® PH 200 as the filler-binder and amylum as the disintegration agent had a significant effect on the Friability of Costus speciosus (CS) extract tablet, in which the combination of both materials can increase the Friability of the tablet. The optimum formula of CS tablet had a composition of Avicel ® PH 200 by 462,5 mg and amylum by 37,5 mg contained in each tablet.
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The Formulation of Pacing (Costus speciosus) Extract Tablet by Using Avicel®Ph 200 As Filler-Binder and Amylum As Disintegration Agent
INDONESIAN JOURNAL OF PHARMACY, 2018Co-Authors: Damayanti Damayanti, Ika Puspita Sari, Angi Nadya Bestari, Tengku Nanda Saifullah Sulaiman, Irfan Muris SetiawanAbstract:Pacing ( Costus speciosus ) is an herbaceous plant that is native to Indonesia and it can be used as a male contraceptive due to spermatogenesis inhibition. The purpose of this study is to find out the composition of optimum Avicel PH 200 ® as the filler-binder and amylum as the disintegration agent and to find out the variations on physical properties of the powder and tablet. The tablets were made by directly compression in 8 runs based on Simplex Lattice Design (SLD) from Design Expert 7.1.5, in which the test on physical properties of powder includes tapping index, water absorption, and moisture content, as well as on the physical properties of tablet, including hardness, Friability, and disintegration time. The results showed that the variation in the composition between Avicel ® PH 200 as the filler-binder and amylum as the disintegration agent had a significant effect on the Friability of Costus speciosus (CS) extract tablet, in which the combination of both materials can increase the Friability of the tablet. The optimum formula of CS tablet had a composition of Avicel ® PH 200 by 462,5 mg and amylum by 37,5 mg contained in each tablet.
