Bulk Properties of Solids

3 Key excerpts on "Bulk Properties of Solids"

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  eBook - ePub

  Dosage Form Design Parameters

  Volume II

  • (Author)
  • 2018(Publication Date)
  • Academic Press

    (Publisher)

  Apart from the interparticle force that exists between the particles, the attractive force can also lead to adhesion of the particles to the surface of the processing equipment. The electrostatic charge that develops on the surface of the instrument and solid particles leads to charge transfer and affects the bulk behavior of the solid. The complex behavior of the particles properties makes it intrinsically difficult to correlate with the solid bulk behavior. Additionally, correlating the contribution of different solid-state properties to an individual particle of powder bulk behavior, as well as global powder bulk is very complicated and affects the quality.

  To develop the correlation between particle properties and powder bulk behavior requires a further understanding of some critical properties. The next section highlights the effects of that particle properties, particularly bulk and surface properties of particles on the processing techniques (milling, blending) and processing parameters. In a further section, the extrinsic factors, the processing parameters, such as temperature and moisture, and their influence on the solid formulation process and the characteristics of the solid dosage form are considered. The individual processing operation is considered and the role of solid state properties on these techniques and ultimately towards the bulk behavior of the solid is reported.

  Taking the lead from interparticle interaction behavior of the pharmaceutical powders and understanding the role of different forces (van der Waals, electrostatic, etc.), the next section discusses the importance and significance of bulk level characteristics in product development.

  6.4 Role of Bulk Level Properties in Formulation Development: Industrial Perspective

  The manufacturing process needed for the development of any dosage form and the role of product and process design in the pharmaceutical industry is depicted in Fig. 6.3 . Additionally, the physicochemical properties of the API highly affect and influence the formulation and manufacturing processes (Liu et al., 2017 ). The particle size and selection of API is the foremost thing for any formulation to be processed as it is the key factor for the development of any dosage form; stability and efficacy of the drug and has a direct impact of formulation performance. Moreover to understand the effect of bulk properties of API on formulation bioavailability and stability, models that can account for the effect of API on dissolution rate are needed to guide formulation efforts (Leturia et al., 2014

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  eBook - ePub

  The Belt Conveyor

  A Concise Basic Course

  • D.V. Subba Rao(Author)
  • 2020(Publication Date)
  • CRC Press

    (Publisher)

  Properties of bulk materials

  Bulk materials or bulk solids consist essentially of many particles or granules of different sizes (and possibly different chemical compositions and densities) randomly grouped together to form a bulk. Bulk materials are stored and handled in volumes often in unpackaged form. Examples include dry powders, granules, flakes and resins. Ores, minerals, coal, fertilizer, sulphur and salt are other common types of bulk materials.

  Bulk materials are generally the most difficult state of matter to handle. Bulk materials handling is characterized by continuous-flow operations, involving materials in an aggregate form. In many cases, the bulk materials assume flow characteristics similar to those of fluids. Elements of a typical bulk materials handling system are as follows:

  1. bins, silos, hoppers, bunkers for storing the material (see Section 8.1 )
  2. discharge devices or feeders (see Section 8.2 )
  3. conveyors
  4. flow aid devices when needed (see Section 8.4 ).

  The following are the most important properties of the bulk materials that affect the design of any materials handling systems.

  2.1 Properties of bulk materials

  2.1.1 Particle size

  Various terms are in use to give a qualitative indication of the size of the particles constituting bulk materials; the word ‘size ’ here is used loosely to mean some sort of average dimension across the particle. Table 2.1 shows the qualitative terms used to describe the size of bulk materials:

  Table 2.1 Qualitative terms for various sizes

  Descriptive term	Typical size range	Examples
  Coarse (or broken) solid	5–100 mm	Coal, ore, aggregates, etc.
  Granular solid	0.3–5 mm	Granulated sugar (0.3–0.5 mm); rice (2–3 mm)
  Particulate solid:
  Coarse powder	100–300 μm	Table salt (200–300 μm)
  Fine powder	10–100 μm	Icing sugar (≅45 μm)
  Superfine powder	1–10 μm	Face powder
  Ultrafine powder	<1 μm	Paint pigments

  The size of the particle of standard configurations such as sphere and cube can easily be specified. For example, the size of a spherical particle is its diameter (d ) and that of a cubical particle is the length of its side (l ), as shown in Figure 2.1

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  Geological and Soil Evidence

  Forensic Applications

  • Kenneth Pye(Author)
  • 2007(Publication Date)
  • CRC Press

    (Publisher)

  59 3 Bulk Properties of Geological and Soil Materials 3.1 Physical Characteristics Several properties of bulk sediments and soils can be used for the purposes of forensic comparison (Table 3.1). These properties may be physical, chemical, biological, or biochemical in character. The selection of which properties to determine in any given situation will inevitably be governed by a number of factors, including the nature and size of the questioned samples, what is known about the character of the crime scene or other comparison samples, and the availability or otherwise of analytical instrumentation, expertise, time, and bud-get. Some bulk properties can be determined relatively quickly with simple equip-ment and at low cost, but others require the use of highly sophisticated equipment that frequently involves longer time periods and significantly higher costs. Different bulk properties vary in terms of their discriminatory power, and an understanding of this is critical for correct interpretation of the significance of results. In most circumstances, it is desirable to make use of several different techniques that provide information about a range of phys-ical, chemical, mineralogical, and biological characteristics. In previous forensic work, these have commonly included color, particle size distribution, bulk mineralogy, chemical composition, and pollen assemblage (e.g., Bremner 1996; Karathanasis and Hajek (2002); Oldfield 1999; Thornton and Crim, 1986; Demmelmeyer and Adam, 1995; Marumo and Sugita, 1998, 2001; Marumo et al., 1999; Brown, 2000; Brown et al., 2002; Lee et al., 2002; Croft and Pye, 2004a, 2004b, 2004c). Only in very rare situations does a single bulk property or type of data provide sufficient information on which to base conclusions about a possible association. 60 Geological and Soil Evidence: Forensic Applications 3.1.1 Color One of the most visually obvious features of a sediment or soil is its color (Bigham and Ciolkosz, 1993).

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