The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Göran Alderborn - One of the best experts on this subject based on the ideXlab platform.
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Effect of Surface Energy on Powder Compactibility
Pharmaceutical Research, 2008Co-Authors: Frauke Fichtner, Denny Mahlin, Ken Welch, Simon Gaisford, Göran AlderbornAbstract:Purpose The influence of surface energy on the compactibility of lactose particles has been investigated. Materials and Methods Three powders were prepared by spray drying lactose solutions without or with low proportions of the surfactant polysorbate 80. Various powder and tablet characterisation procedures were applied. The surface energy of the powders was characterized by Inverse Gas Chromatography and the compressibility of the powders was described by the relationship between tablet porosity and compression pressure. The compactibility of the powders was analyzed by studying the evolution of tablet tensile strength with increasing compaction pressure and porosity. Results All powders were amorphous and similar in particle size, shape, and surface area. The compressibility of the powders and the microstructure of the formed tablets were equal. However, the compactibility and dispersive surface energy was dependent of the composition of the powders. Conclusion The decrease in tablet strength correlated to the decrease in powder surface energy at constant tablet porosities. This supports the idea that tablet strength is controlled by formation of intermolecular forces over the areas of contact between the particles and that the strength of these bonding forces is controlled by surface energy which, in turn, can be altered by the presence of surfactants.
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Effect of surface energy on powder compactibility.
Pharm Res, 2008Co-Authors: Göran AlderbornAbstract:The influence of surface energy on the compactibility of lactose particles has been investigated.
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effect of preparation method on Compactability of paracetamol granules and agglomerates
International Journal of Pharmaceutics, 2007Co-Authors: Frauke Fichtner, Ake C Rasmuson, Eva Alander, Göran AlderbornAbstract:The objective of this study was to investigate the effect of fracture strength of paracetamol particles on their Compactability. For this purpose two series of paracetamol particles were prepared by crystal agglomeration and by granulation using different solvents. A free flowing particle size fraction of all types of particles was characterized with respect to their shape, degree of agglomeration and single fracture strength. The powders were compressed to tablets and the compression mechanism of the particles and the evolution in tablet micro-structure were assessed by compression parameters derived from the Heckel and Kawakita equations and by a tablet permeabililty coefficient. Tablet tensile strength and porosity were determined. The degree of deformation and fragmentation during compression varied between agglomerates and granules and was dependent on their failure strength. The granules varied in Compactability with particle failure strength while the agglomerates showed limited variation. It is proposed that, the dominant mechanism of compression for the granules was permanent deformation while for the agglomerates it was fragmentation. It was thus found that the compression mechanism of the particles was dependent on both the degree of agglomeration and the particle failure strength.
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the effect of particle fragmentation and deformation on the interparticulate bond formation process during powder compaction
Pharmaceutical Research, 1995Co-Authors: Maria Eriksson, Göran AlderbornAbstract:Purpose. The compression behaviour and the Compactability of particles have been studied. In addition, an expression describing the bond strength over a tablet cross section was derived and these calculated values were compared with the experimentally determined tablet tensile strength values.
Agus Setyo Muntohar - One of the best experts on this subject based on the ideXlab platform.
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Effect of the cement-rice husk ash on the plasticity and compaction of soil
2020Co-Authors: E A Basha, Roslan Hashim, Agus Setyo MuntoharAbstract:The chemical stabilisation of soils was studied by using cement and rice husk ash. Three types of soils, residual soils, kaolinite and bentonite, were used in the study. The experimental study included the evaluation of the main index properties of the soil and compaction, along with a characterisation of the materials through X-Ray diffraction. Test results show that both cement and rice husk ash reduces the plasticity of soils. In term of Compactability, addition of rice husk ash and cement decreases the maximum dry density and increases the optimum moisture content. From the viewpoint of plasticity, compaction characteristics, and economy, addition of 6 - 8 percent cement and 10 - 15 percent rice husk ash are recommended as an optimum amount.
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stabilization of residual soil with rice husk ash and cement
Construction and Building Materials, 2005Co-Authors: E A Basha, Hilmi Bin Mahmud, Roslan Hashim, Agus Setyo MuntoharAbstract:Abstract Stabilization of residual soils is studied by chemically using cement and rice husk ash. Investigation includes the evaluation of such properties of the soil as compaction, strength, and X-ray diffraction. Test results show that both cement and rice husk ash reduce the plasticity of soils. In term of Compactability, addition of rice husk ash and cement decreases the maximum dry density and increases the optimum moisture content. From the viewpoint of plasticity, compaction and strength characteristics, and economy, addition of 6–8% cement and 10–15% rice husk ash is recommended as an optimum amount.
Horstmichael Ludwig - One of the best experts on this subject based on the ideXlab platform.
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effect of rice husk ash and other mineral admixtures on properties of self compacting high performance concrete
Materials & Design, 2016Co-Authors: Ha Thanh Le, Horstmichael LudwigAbstract:Abstract The present study aims investigating the effects of superplasticizer (SP) and of mineral admixtures on self-Compactability and compressive strength of mortar and of self-compacting high performance concrete (SCHPC). The results show that SP dosages higher than the SP saturation dosage (SSD) did not influence flowability and plastic viscosity, and induced the bleeding. Contrary to fly ash (FA)/silica fume (SF), the incorporation of rice husk ash (RHA) increased the SSD of mortar, slightly decreased filling and passing abilities and significantly increased plastic viscosity and segregation resistance of SCHPC. The incorporation of RHA also eliminated the bleeding of mortar and SCHPC. Having a macro-mesoporous structure, RHA can be used as a viscosity modifying admixture, and improve the robustness of SCHPC with respect to the variation in the high SP dosage. Supposedly, with the coarse particle size and large specific surface area, RHA induces great intermolecular attraction forces with water and SP. Similar to SF, RHA was effective in improving compressive strength of SCHPC, particularly at a larger percentage cement replacement and at later ages. RHA and FA had synergistic effect on self-Compactability and compressive strength. Compressive strength of SCHPC incorporating 20 wt.% FA and 20 wt.% RHA reached about 130 MPa after 56 days.
E A Basha - One of the best experts on this subject based on the ideXlab platform.
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Effect of the cement-rice husk ash on the plasticity and compaction of soil
2020Co-Authors: E A Basha, Roslan Hashim, Agus Setyo MuntoharAbstract:The chemical stabilisation of soils was studied by using cement and rice husk ash. Three types of soils, residual soils, kaolinite and bentonite, were used in the study. The experimental study included the evaluation of the main index properties of the soil and compaction, along with a characterisation of the materials through X-Ray diffraction. Test results show that both cement and rice husk ash reduces the plasticity of soils. In term of Compactability, addition of rice husk ash and cement decreases the maximum dry density and increases the optimum moisture content. From the viewpoint of plasticity, compaction characteristics, and economy, addition of 6 - 8 percent cement and 10 - 15 percent rice husk ash are recommended as an optimum amount.
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stabilization of residual soil with rice husk ash and cement
Construction and Building Materials, 2005Co-Authors: E A Basha, Hilmi Bin Mahmud, Roslan Hashim, Agus Setyo MuntoharAbstract:Abstract Stabilization of residual soils is studied by chemically using cement and rice husk ash. Investigation includes the evaluation of such properties of the soil as compaction, strength, and X-ray diffraction. Test results show that both cement and rice husk ash reduce the plasticity of soils. In term of Compactability, addition of rice husk ash and cement decreases the maximum dry density and increases the optimum moisture content. From the viewpoint of plasticity, compaction and strength characteristics, and economy, addition of 6–8% cement and 10–15% rice husk ash is recommended as an optimum amount.
Peter Kleinebudde - One of the best experts on this subject based on the ideXlab platform.
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critical evaluation of root causes of the reduced Compactability after roll compaction dry granulation
Journal of Pharmaceutical Sciences, 2015Co-Authors: Johanna Mosig, Peter KleinebuddeAbstract:ABSTRACT: The influence of lubrication and particle size on the reduced Compactability after dry granulation was investigated. Powder cellulose, lactose, magnesium carbonate, and two types of microcrystalline cellulose were roll compacted, granulated, and sieved into particle fractions. Particle fractions were compressed into tablets using internal and external lubrication. Internal lubrication resulted in an overlubrication of the granule material compared with the powder material. This resulted in extraordinary high reduction of Compactability after dry granulation for lubricant-sensitive materials. The granule size can cause differences in strength, whereby the degree of this effect was material dependent. The loss in strength with increasing compaction force was comparable for different particles sizes of one material, suggesting a change in material properties independently of the size. Granule hardening could be one reason as for higher compaction forces the integrity of the granule structure survived the compression step. The results demonstrated that granule lubrication mainly influence the degree of the reduced Compactability after dry granulation and must be considered for the evaluation of mechanism for this phenomenon. Hardening of the material as well as size enlargement will cause the loss in strength after recompression, but the influence of both depends strongly on the material. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.
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Increased compactibility of acetames after roll compaction.
European Journal of Pharmaceutics and Biopharmaceutics, 2010Co-Authors: Theresia Kuntz, Martin Alexander Schubert, Peter KleinebuddeAbstract:A common technique for manufacturing granules in a continuous way is the combination of roll compaction and subsequent milling. Roll compaction can considerably impact tableting performance of a material. The purpose of this study was to investigate the influence of roll compaction/dry granulation on the compaction behavior of acetames, a class of active pharmaceutical substances, which are mainly used for the treatment of central nervous diseases. Some representatives of acetames were roll compacted and then compressed into tablets. Compactibility of granules was compared with the compaction behavior of the directly compressed drug powders. In contrast to many other materials, the roll compaction step induced an increase in compactibility for all investigated acetames. Specific surface areas of the untreated and the roll compacted drugs were determined by nitrogen adsorption. The raise in compactibility observed was accompanied by an increase in specific surface area during roll compaction.