Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Vita. / Includes bibliographical references. / by Ellen Schwartz Tormey. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Includes bibliographical references. / by Mark V. Parish. / M.S.

Approximately 80% of pharmaceutical products and the ingredients required for their manufacture are in powder form. The solid dosage form (tablets and capsules) is manufactured by either dry-blending of fine powder ingredients or combining the ingredients in a wet granulation step, followed by drying. Arching, ratholing, caking, segregation and flooding are some of the commonly encountered flow problems in the handling of fine powders. These problems lead to losses worth thousands of dollars at production scale. Poor powder flowability is a consequence of the combined effects of many variables, including improper equipment design, particle size, size distribution, shape, moisture content and surface texture. In the present work, a systematic study has been performed to determine the relationship between the flowability of fine powders and their physical properties of mean size and size distribution, density and shape.<p> Flowability studies were done on six different powders: the NutraSweet® Brand sweetener (aspartame), Respitose ML001, Alpha-D-Lactose monohydrate, the pharmaceutical binder Methocel (R) F50 Premium Hydroxypropyl methylcellulose- HPMC, a placebo pharmaceutical granulate, and common pastry flour. Scanning electron microscopy (SEM) and stereomicroscopy were used for particle shape and size analysis. Particle size distribution was determined using the laser light scattering technique. Powder flowability was measured using shear strength, angle of repose, and tapped-to-bulk density measurements. A novel method of measuring the dynamic angle of repose using electrical capacitance tomography (ECT) was developed. <p> Analysis of the images from microscopy revealed that the particles of aspartame and HPMC powders were elongated, the particles of ML001, pastry flour and lactose monohydrate powders were irregular, and the particles of placebo granulate were nearly spherical. Particle size was found to be the most reliable indicator of powder flowability, with decreasing particle size corresponding to lower flowability; however other parameters such as particle elongation and irregularity, were also found to have an influence on powder flowability. Although HPMC and pastry flour had similar particle sizes, they exhibited differences in flowability. This can be explained by the greater irregularity of the flour particles. Particle irregularity may cause mechanical interlocking between the particles, thus reducing powder flowability. ECT was found to be a promising non-intrusive tool for the measurement of the dynamic angle of repose. Unlike other methods for the measurement of dynamic angle of repose, the results obtained from ECT were not influenced by the effect of end caps. The present technique could be used by pharmaceutical industries in process analytical technology (PAT) for the detection and elimination of potential flow problems early in the manufacturing process.

Approximately 80% of pharmaceutical products and the ingredients required for their manufacture are in powder form. The solid dosage form (tablets and capsules) is manufactured by either dry-blending of fine powder ingredients or combining the ingredients in a wet granulation step, followed by drying. Arching, ratholing, caking, segregation and flooding are some of the commonly encountered flow problems in the handling of fine powders. These problems lead to losses worth thousands of dollars at production scale. Poor powder flowability is a consequence of the combined effects of many variables, including improper equipment design, particle size, size distribution, shape, moisture content and surface texture. In the present work, a systematic study has been performed to determine the relationship between the flowability of fine powders and their physical properties of mean size and size distribution, density and shape.<p> Flowability studies were done on six different powders: the NutraSweet® Brand sweetener (aspartame), Respitose ML001, Alpha-D-Lactose monohydrate, the pharmaceutical binder Methocel (R) F50 Premium Hydroxypropyl methylcellulose- HPMC, a placebo pharmaceutical granulate, and common pastry flour. Scanning electron microscopy (SEM) and stereomicroscopy were used for particle shape and size analysis. Particle size distribution was determined using the laser light scattering technique. Powder flowability was measured using shear strength, angle of repose, and tapped-to-bulk density measurements. A novel method of measuring the dynamic angle of repose using electrical capacitance tomography (ECT) was developed. <p> Analysis of the images from microscopy revealed that the particles of aspartame and HPMC powders were elongated, the particles of ML001, pastry flour and lactose monohydrate powders were irregular, and the particles of placebo granulate were nearly spherical. Particle size was found to be the most reliable indicator of powder flowability, with decreasing particle size corresponding to lower flowability; however other parameters such as particle elongation and irregularity, were also found to have an influence on powder flowability. Although HPMC and pastry flour had similar particle sizes, they exhibited differences in flowability. This can be explained by the greater irregularity of the flour particles. Particle irregularity may cause mechanical interlocking between the particles, thus reducing powder flowability. ECT was found to be a promising non-intrusive tool for the measurement of the dynamic angle of repose. Unlike other methods for the measurement of dynamic angle of repose, the results obtained from ECT were not influenced by the effect of end caps. The present technique could be used by pharmaceutical industries in process analytical technology (PAT) for the detection and elimination of potential flow problems early in the manufacturing process.

No description available.

Thesis (M.S.)--Engineering, Georgia Institute of Technology, 2004. / McDowell, David, Committee Chair; Neu, Richard, Committee Member; Lee, Jim, Committee Member; Cochran, Joe, Committee Member. Includes bibliographical references (leaves 159-162).

Thesis (doctoral)--Helsinki University of Technology, 2001. / Includes bibliographical references. Also available on the World Wide Web.

Recent studies indicate B4C nanopowder may provide additional advantages without loss of established properties. In this study, preliminary forms of graphite-coated B4C nanopowders on the order of 20-40 nm with various additives were sintered and analyzed. Methanol washing was performed on the powders to remove most of the B2O3 impurity usually present. XRD analysis of the powders verified the nanograined nature and, to some extent, the amount of amorphous material within the powders. A dilatometer furnace was used to track the dimensional changes during sintering, and densities of sintered samples were compared to green compact densities. The onset of sintering occurred at various temperatures depending on the dopant and its amount, most often occurring at higher temperatures than expected. This was likely due first to volatilization of residual B2O3 and then to the graphite coatings of the powders preventing direct B4C-B4C contact. Double-stage sintering, where sintering is either slowed, arrested or reversed and then re-accelerated, occurred in all but one sample. Samples with sintered densities greater than 93% theoretical density were hot isostatically pressed (HIP) with the expectation that the post-HIP density would be 100% theoretical density. Ultimately, post-HIP densities increased less than 2% compared to sintered densities.

Thesis (Ph.D.)--McMaster University, 2005. / Supervisor: Ken Coley. Includes bibliographical references (leaves 204-211).

Thesis (doctoral)--Technische Universiteit Delft, 1998. / Includes bibliographical references.