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Storage and Flow of Solids

01 Jan 1964-
About: The article was published on 1964-01-01 and is currently open access. It has received 585 citations till now. The article focuses on the topics: Flow (mathematics).
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Journal ArticleDOI
TL;DR: In this paper, the effect of moisture content on the packing and flow properties of lignite powders was experimentally investigated using an FT4 Powder Rheometer and a PT-X powder tester to gain flow parameters like angle of repose, packing density, Hausner ratio, and shear test profiles.
Abstract: The effect of moisture content on the packing and flow properties of lignite powders was experimentally investigated using an FT4 Powder Rheometer and a PT-X powder tester to gain flow parameters like angle of repose, packing density, Hausner ratio, and shear test profiles. Flow criteria showed that flowability decreased with increasing moisture content. The flowability and packing properties were different both above and below the critical moisture content. To explain this phenomenon, a model was proposed to relate the inter-particle force at the microscale from shear test data to the packing properties at the macroscale. The model was further modified to predict effects of moisture content on flowability and packing properties. The term ρpd3gφ2e was defined to describe the influence of water addition.

16 citations

01 Jan 2000
TL;DR: In this paper, it was shown that fine powders often exhibit significant two-phase (solid/gas) interactions when they are handled in bins, hoppers, and processing vessels.
Abstract: Fine powders often exhibit significant twophase (solid/gas) interactions when they are handled in bins, hoppers, and processing vessels. As a result, numerous and more complex flow problems can occur which are not observed with larger particle bulk solids. The powder’s flow pattern has a major effect on the development of certain flow problems, especially flooding. This can usually be overcome by using mass flow designs. Unfortunately, when mass flow is achieved the powder’s discharge rate through a hopper outlet may be severely restricted.

16 citations

Journal ArticleDOI
TL;DR: In this article, a theory that can be used to model the cohesive behavior of bulk materials based on capillary forces between particles is presented, which is useful in describing process flow behavior.

15 citations

Journal ArticleDOI
TL;DR: Melt granule formulations before compression showed good flow properties, were larger in particle size than individual starting API materials and were easily compressible, and a suitable platform for developing direct compressible high-dose immediate-release solid dosage forms of FDC products.
Abstract: The development of oral solid dosage forms, such as tablets that contain a high dose of drug(s), requires polymers and other additives to be incorporated at low levels as possible, to keep the final tablet weight low, and, correspondingly, the dosage form size small enough to be acceptable from a patient perspective. Additionally, a multi-step batch-based manufacturing process is usually required for production of solid dosage forms. This study presents the development and production, by twin-screw melt granulation technology, of a high-dose immediate-release fixed-dose combination (FDC) product of metformin hydrochloride (MET) and sitagliptin phosphate (SIT), with drug loads of 80% w/w and 6% w/w, respectively. For an 850/63 mg dose of MET/SIT, the final weight of the caplets was approximately 1063 mg compared with 1143 mg for the equivalent dose in Janumet®, the marketed product. Mixtures of the two drugs and polymers were melt-granulated at temperatures below the individual melting temperatures of MET and SIT (231.65 and 213.89°C, respectively) but above the glass transition temperature or melting temperature of the binder(s) used. By careful selection of binders, and processing conditions, direct compressed immediate-release caplets with desired product profiles were successfully produced. The melt granule formulations before compression showed good flow properties, were larger in particle size than individual starting API materials and were easily compressible. Melt granulation is a suitable platform for developing direct compressible high-dose immediate-release solid dosage forms of FDC products.

15 citations

Book ChapterDOI
01 Jan 1991
TL;DR: In this article, the authors observed that the lateral pressure on the silo wall increases immediately after the beginning of emptying and can be a multiple of the one during filling, and stress fluctuations are registered during the whole emptying process in big and in model silos as well.
Abstract: After opening a silo bottom outlet some characteristic phenomena can be observed: The lateral pressure on the silo wall increases immediately after the beginning of emptying and can be a multiple of the one during filling. Shear zones come into being along the silo wall and, for a dense fill, also inside the flowing granular material. The dilatancy constraint in the shear zones (caused by the stiffness of neighbouring material) results in a scale effect in model silos, i.e. an additional increase of dimensionless wall stresses. Stress fluctuations are registered during the whole emptying process in big and in model silos as well.

15 citations