Measurement of Porosity in Granular Particle Distributions Using Adaptive Thresholding

Bloom, Michael; Russell, Michael J.; Kustau, Aliaksei; Mandayam, Shreekanth; Sukumaran, Beena

doi:10.1109/tim.2010.2040902

Cited by 11 publications

(6 citation statements)

References 16 publications

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“…The grain patterns in the lactose tablets are much smaller and occur at a much lower frequency in comparison to Eudragit and HPMC; this is a result of the tablet reaching its solid limit. The grain boundaries can be a result of the particle shape prior to compaction as well as the mechanical properties of the particles 44. In Figure 4, the X-ray cross-sections contain ring artifacts, resulting from errors produced using the back projection algorithm, which increase with the perpendicular distance from the central slice and the filters used in reconstruction; these enhance frequencies, for example, high frequencies produced by changing sensitivities in adjacent detector elements in the charge coupled device 45.…”

Section: Resultsmentioning

confidence: 99%

“…The grain boundaries can be a result of the particle shape prior to compaction as well as the mechanical properties of the particles. 44 In Figure 4, the X-ray cross-sections contain ring artifacts, resulting from errors produced using the back projection algorithm, which increase with the perpendicular distance from the central slice and the filters used in reconstruction; these enhance frequencies, for example, high frequencies produced by changing sensitivities in adjacent detector elements in the charge coupled device. 45 This is a systematic error in the reconstruction and does not result in significant errors in the subsequent analysis.…”

Section: Microstructure Analysismentioning

confidence: 99%

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Diffusion and Swelling Measurements in Pharmaceutical Powder Compacts Using Terahertz Pulsed Imaging

Yassin

Lin

et al. 2015

Journal of Pharmaceutical Sciences

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Tablet dissolution is strongly affected by swelling and solvent penetration into its matrix. A terahertz-pulsed imaging (TPI) technique, in reflection mode, is introduced as a new tool to measure one-dimensional swelling and solvent ingress in flat-faced pharmaceutical compacts exposed to dissolution medium from one face of the tablet. The technique was demonstrated on three tableting excipients: hydroxypropylmethyl cellulose (HPMC), Eudragit RSPO, and lactose. Upon contact with water, HPMC initially shrinks to up to 13% of its original thickness before undergoing expansion. HPMC and lactose were shown to expand to up to 20% and 47% of their original size in 24 h and 13 min, respectively, whereas Eudragit does not undergo dimensional change. The TPI technique was used to measure the ingress of water into HPMC tablets over a period of 24 h and it was observed that water penetrates into the tablet by anomalous diffusion. X-ray microtomography was used to measure tablet porosity alongside helium pycnometry and was linked to the results obtained by TPI. Our results highlight a new application area of TPI in the pharmaceutical sciences that could be of interest in the development and quality testing of advanced drug delivery systems as well as immediate release formulations. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:1658–1667, 2015

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Section: Resultsmentioning

confidence: 99%

Section: Microstructure Analysismentioning

confidence: 99%

Diffusion and Swelling Measurements in Pharmaceutical Powder Compacts Using Terahertz Pulsed Imaging

Yassin

Lin

et al. 2015

Journal of Pharmaceutical Sciences

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“…Atkins and McBride (1992), Curry et al (2004) and Dickinson and Ward (1994) point-counted the upper surface of thin sections of epoxy-or superglue-impregnated samples in reflected light. Among the various methods that have been applied by different researchers (Beard and Weyl, 1973;Roberts et al, 1998), it is worth mentioning the use of diver cores with in-situ conductivity probes and X-ray computed tomography (CT) scanning techniques (Bloom et al, 2010;Briggs et al, 2010). However, Dickinson and Ward (1994) have noted the difficulty of obtaining in-situ sand samples in which porosities can be measured without disturbing the loosely packed grains.…”

Section: Materials and Methodologymentioning

confidence: 99%

“…Numerous studies of geological and geotechnical engineering applications to measure the maximum and minimum porosities for different grain size distributions and/or sorting coefficients have been conducted (Bloom et al, 2010;Curry et al, 2004;Gaither, 1953;King, 1899). However, none of these authors studied porosity for beach-monitoring purposes.…”

Section: Introductionmentioning

confidence: 99%

Beach nourishment effects on sand porosity variability

Román-Sierra

Muñoz-Pérez

Navarro-Pons

2014

Coastal Engineering

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A standard assumption in coastal engineering is that the porosity of natural beach sand (non-cohesive) is 40%. However, is this assumption correct for all beach sand? This paper proposes an accurate and simplified method to assess changes in sand porosity after beach nourishment by means of in-situ density surveys through a nuclear densimeter. This novel application has been applied to different beaches in the southwest of Spain according to the tidal range, grain size and beach morphology in several terms. General results show that sand porosities range from 25.6% to 43.4% after beach nourishment works. This research can be considered a support tool in coastal engineering to find shifting sand volumes as a result of sand porosity variability after beach nourishment and later marine influence.

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“…This makes it possible to establish the characteristics of the porous structure and obtain predictive estimates of various physical properties of the object under study (gas permeability, thermal conductivity etc.) as a result of one measuring through the use of computer analysis methods [30,31].…”

Section: Observation Of the Porous Structure And Its Disappearance After Thermal-radiation Modification In Polytetrafluoroethylenementioning

confidence: 99%

Structure of Polytetrafluoroethylene Modified by the Combined Action of γ-Radiation and High Temperatures

et al. 2021

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By means of X-ray computed microtomography (XCMT), the existence of a developed porous structure with an average pore diameter of ~3.5 μm and pore content of ~1.1 vol.% has been revealed in unirradiated polytetrafluoroethylene (PTFE). It has been found that the combined action of gamma radiation (absorbed dose per PTFE of ~170 kGy) and high temperatures (327–350 °C) leads to the disappearance of the porous structure and the formation of several large pores with sizes from 30 to 50 μm in the bulk of thermal-radiation modified PTFE (TRM-PTFE). It has been established by X-ray diffraction (XRD) analysis that the thermal-radiation modification of PTFE leads to an increase in the interplanar spacings, the degree of crystallinity and the volume of the unit cell, as well as to a decrease in the size of crystals and the X-ray density of the crystalline phase in comparison with the initial polymer. It is assumed that the previously-established effect of improving the deformation-strength and tribological properties of the TRM-PTFE can be due not only to the radiation cross-linking of polymer chains but also to the disappearance of the pore system and to the ordering of the crystalline phase of PTFE

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Measurement of Porosity in Granular Particle Distributions Using Adaptive Thresholding

Cited by 11 publications

References 16 publications

Diffusion and Swelling Measurements in Pharmaceutical Powder Compacts Using Terahertz Pulsed Imaging

Diffusion and Swelling Measurements in Pharmaceutical Powder Compacts Using Terahertz Pulsed Imaging

Beach nourishment effects on sand porosity variability

Structure of Polytetrafluoroethylene Modified by the Combined Action of γ-Radiation and High Temperatures

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