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Charles D Shackelford - One of the best experts on this subject based on the ideXlab platform.

  • soil water characteristic curves and dual porosity of sand Diatomaceous Earth mixtures
    Journal of Geotechnical and Geoenvironmental Engineering, 2001
    Co-Authors: Craig A Burger, Charles D Shackelford
    Abstract:

    The soil-water characteristic curves (SWCCs) for sand–pelletized Diatomaceous Earth mixtures are measured. The measured SWCCs are bimodal due to two distinct pore-size distributions associated with the microscopic (intrapellet) and macroscopic (interpellet) porosity regions of the pelletized Diatomaceous Earth. The measured data for the bimodal SWCCs are fit with modified forms of the Brooks-Corey, van Genuchten, and Fredlund-Xing SWCC functions, and the microscopic and macroscopic porosity portions of the mixtures are determined from the SWCC fits. Both the total and the microscopic porosity of the mixtures increase with increased percentage by dry weight of Diatomaceous Earth in the mixtures. However, the macroscopic porosity of the mixtures is essentially independent of the Diatomaceous Earth content due to the similarity in the particle-size distributions of the sand and the Diatomaceous Earth. The results suggest that sand–Diatomaceous Earth mixtures may be useful in applications where an increase in...

  • evaluating dual porosity of pelletized Diatomaceous Earth using bimodal soil water characteristic curve functions
    Canadian Geotechnical Journal, 2001
    Co-Authors: Craig A Burger, Charles D Shackelford
    Abstract:

    Soil-water characteristic curve data for specimens containing either ~1 mm or ~2 mm diameter pellets of processed Diatomaceous Earth are measured using a variety of methods (Tempe cell, pressure plate, filter paper, and chilled-mirror psychrometer). The measured soil-water characteristic curve data are bimodal, reflecting both the microscopic porosity region within the individual pellets, or intrapellet porosity, and the macroscopic porosity region between the pellets, or interpellet porosity. The bimodal distributions are consistent with scanning electron micrographs that show the existence of microscopic pores within each pellet, and the relatively high total porosities (0.725 and 0.764) for the coarse-grained Diatomaceous Earth specimens. The measured soil-water characteristic curve data are fit with modified forms of the Brooks–Corey, van Genuchten, and Fredlund–Xing soil-water characteristic curve functions to account for the bimodal shapes of the measured data. The average microscopic porosities res...

  • Soil-Water Characteristic Curves and Dual Porosity of Sand–Diatomaceous Earth Mixtures
    Journal of Geotechnical and Geoenvironmental Engineering, 2001
    Co-Authors: Craig A Burger, Charles D Shackelford
    Abstract:

    The soil-water characteristic curves (SWCCs) for sand–pelletized Diatomaceous Earth mixtures are measured. The measured SWCCs are bimodal due to two distinct pore-size distributions associated with the microscopic (intrapellet) and macroscopic (interpellet) porosity regions of the pelletized Diatomaceous Earth. The measured data for the bimodal SWCCs are fit with modified forms of the Brooks-Corey, van Genuchten, and Fredlund-Xing SWCC functions, and the microscopic and macroscopic porosity portions of the mixtures are determined from the SWCC fits. Both the total and the microscopic porosity of the mixtures increase with increased percentage by dry weight of Diatomaceous Earth in the mixtures. However, the macroscopic porosity of the mixtures is essentially independent of the Diatomaceous Earth content due to the similarity in the particle-size distributions of the sand and the Diatomaceous Earth. The results suggest that sand–Diatomaceous Earth mixtures may be useful in applications where an increase in...

Craig A Burger - One of the best experts on this subject based on the ideXlab platform.

  • soil water characteristic curves and dual porosity of sand Diatomaceous Earth mixtures
    Journal of Geotechnical and Geoenvironmental Engineering, 2001
    Co-Authors: Craig A Burger, Charles D Shackelford
    Abstract:

    The soil-water characteristic curves (SWCCs) for sand–pelletized Diatomaceous Earth mixtures are measured. The measured SWCCs are bimodal due to two distinct pore-size distributions associated with the microscopic (intrapellet) and macroscopic (interpellet) porosity regions of the pelletized Diatomaceous Earth. The measured data for the bimodal SWCCs are fit with modified forms of the Brooks-Corey, van Genuchten, and Fredlund-Xing SWCC functions, and the microscopic and macroscopic porosity portions of the mixtures are determined from the SWCC fits. Both the total and the microscopic porosity of the mixtures increase with increased percentage by dry weight of Diatomaceous Earth in the mixtures. However, the macroscopic porosity of the mixtures is essentially independent of the Diatomaceous Earth content due to the similarity in the particle-size distributions of the sand and the Diatomaceous Earth. The results suggest that sand–Diatomaceous Earth mixtures may be useful in applications where an increase in...

  • evaluating dual porosity of pelletized Diatomaceous Earth using bimodal soil water characteristic curve functions
    Canadian Geotechnical Journal, 2001
    Co-Authors: Craig A Burger, Charles D Shackelford
    Abstract:

    Soil-water characteristic curve data for specimens containing either ~1 mm or ~2 mm diameter pellets of processed Diatomaceous Earth are measured using a variety of methods (Tempe cell, pressure plate, filter paper, and chilled-mirror psychrometer). The measured soil-water characteristic curve data are bimodal, reflecting both the microscopic porosity region within the individual pellets, or intrapellet porosity, and the macroscopic porosity region between the pellets, or interpellet porosity. The bimodal distributions are consistent with scanning electron micrographs that show the existence of microscopic pores within each pellet, and the relatively high total porosities (0.725 and 0.764) for the coarse-grained Diatomaceous Earth specimens. The measured soil-water characteristic curve data are fit with modified forms of the Brooks–Corey, van Genuchten, and Fredlund–Xing soil-water characteristic curve functions to account for the bimodal shapes of the measured data. The average microscopic porosities res...

  • Soil-Water Characteristic Curves and Dual Porosity of Sand–Diatomaceous Earth Mixtures
    Journal of Geotechnical and Geoenvironmental Engineering, 2001
    Co-Authors: Craig A Burger, Charles D Shackelford
    Abstract:

    The soil-water characteristic curves (SWCCs) for sand–pelletized Diatomaceous Earth mixtures are measured. The measured SWCCs are bimodal due to two distinct pore-size distributions associated with the microscopic (intrapellet) and macroscopic (interpellet) porosity regions of the pelletized Diatomaceous Earth. The measured data for the bimodal SWCCs are fit with modified forms of the Brooks-Corey, van Genuchten, and Fredlund-Xing SWCC functions, and the microscopic and macroscopic porosity portions of the mixtures are determined from the SWCC fits. Both the total and the microscopic porosity of the mixtures increase with increased percentage by dry weight of Diatomaceous Earth in the mixtures. However, the macroscopic porosity of the mixtures is essentially independent of the Diatomaceous Earth content due to the similarity in the particle-size distributions of the sand and the Diatomaceous Earth. The results suggest that sand–Diatomaceous Earth mixtures may be useful in applications where an increase in...

C Ulrichs - One of the best experts on this subject based on the ideXlab platform.

  • action of amorphous Diatomaceous Earth against different stages of the stored product pests tribolium confusum tenebrio molitor sitophilus granarius and plodia interpunctella
    Journal of Stored Products Research, 2001
    Co-Authors: I I Mewis, C Ulrichs
    Abstract:

    Environmental and human health problems associated with the use of synthetic pesticides have prompted the demand for non-polluting, biologically specific insecticides. The current study tested the use and action of Diatomaceous Earth against several stored product pests. Fossil Shield 1 applied to wooden plates was lethal to adult Tenebrio molitor and Tribolium confusum, but larvae of the mealworm were unaAected. Beetles died within 14 days exposure in the absence of food to a dose of 2 and 4 g/m 2 , but mortality was reduced in those fed grain bran. Fossil Shield 1 was lethal to first instar larvae of Plodia interpunctella, but not lethal to older larval stages. Two-week old larvae of T. confusum were more sensitive to Diatomaceous Earth than P. interpunctella at the same age. Contact with Diatomaceous Earth caused adult Sitophilus granarius, T. molitor and T. confusum to lose weight and reduced their water content, suggesting disruption of ‘‘the water barrier’’. Death of stored product insects treated with Diatomaceous Earth decreased with increased r.h., due to reduced transpiration through the cuticle. High r.h. delays, or above 60% can prevent, the drying action of Diatomaceous Earth. 7 2000 Elsevier Science Ltd. All rights reserved.

  • action of amorphous Diatomaceous Earth against different stages of the stored product pests tribolium confusum tenebrio molitor sitophilus granarius and plodia interpunctella
    Journal of Stored Products Research, 2001
    Co-Authors: I I Mewis, C Ulrichs
    Abstract:

    Environmental and human health problems associated with the use of synthetic pesticides have prompted the demand for non-polluting, biologically specific insecticides. The current study tested the use and action of Diatomaceous Earth against several stored product pests. Fossil Shield(R) applied to wooden plates was lethal to adult Tenebrio molitor and Tribolium confusum, but larvae of the mealworm were unaffected. Beetles died within 14 days exposure in the absence of food to a dose of 2 and 4 g/m(2), but mortality was reduced in those fed grain bran. Fossil Shield(R) was lethal to first instar larvae of Plodia interpunctella, but not lethal to older larval stages. Two-week old larvae of T. confusum were more sensitive to Diatomaceous Earth than P. interpunctella at the same age. Contact with Diatomaceous Earth caused adult Sitophilus granarius, T. molitor and T. confusum to lose weight and reduced their water content, suggesting disruption of "the water barrier". Death of stored product insects treated with Diatomaceous Earth decreased with increased r.h., due to reduced transpiration through the cuticle. High r.h. delays, or above 60% can prevent, the drying action of Diatomaceous Earth.

I I Mewis - One of the best experts on this subject based on the ideXlab platform.

  • action of amorphous Diatomaceous Earth against different stages of the stored product pests tribolium confusum tenebrio molitor sitophilus granarius and plodia interpunctella
    Journal of Stored Products Research, 2001
    Co-Authors: I I Mewis, C Ulrichs
    Abstract:

    Environmental and human health problems associated with the use of synthetic pesticides have prompted the demand for non-polluting, biologically specific insecticides. The current study tested the use and action of Diatomaceous Earth against several stored product pests. Fossil Shield 1 applied to wooden plates was lethal to adult Tenebrio molitor and Tribolium confusum, but larvae of the mealworm were unaAected. Beetles died within 14 days exposure in the absence of food to a dose of 2 and 4 g/m 2 , but mortality was reduced in those fed grain bran. Fossil Shield 1 was lethal to first instar larvae of Plodia interpunctella, but not lethal to older larval stages. Two-week old larvae of T. confusum were more sensitive to Diatomaceous Earth than P. interpunctella at the same age. Contact with Diatomaceous Earth caused adult Sitophilus granarius, T. molitor and T. confusum to lose weight and reduced their water content, suggesting disruption of ‘‘the water barrier’’. Death of stored product insects treated with Diatomaceous Earth decreased with increased r.h., due to reduced transpiration through the cuticle. High r.h. delays, or above 60% can prevent, the drying action of Diatomaceous Earth. 7 2000 Elsevier Science Ltd. All rights reserved.

  • action of amorphous Diatomaceous Earth against different stages of the stored product pests tribolium confusum tenebrio molitor sitophilus granarius and plodia interpunctella
    Journal of Stored Products Research, 2001
    Co-Authors: I I Mewis, C Ulrichs
    Abstract:

    Environmental and human health problems associated with the use of synthetic pesticides have prompted the demand for non-polluting, biologically specific insecticides. The current study tested the use and action of Diatomaceous Earth against several stored product pests. Fossil Shield(R) applied to wooden plates was lethal to adult Tenebrio molitor and Tribolium confusum, but larvae of the mealworm were unaffected. Beetles died within 14 days exposure in the absence of food to a dose of 2 and 4 g/m(2), but mortality was reduced in those fed grain bran. Fossil Shield(R) was lethal to first instar larvae of Plodia interpunctella, but not lethal to older larval stages. Two-week old larvae of T. confusum were more sensitive to Diatomaceous Earth than P. interpunctella at the same age. Contact with Diatomaceous Earth caused adult Sitophilus granarius, T. molitor and T. confusum to lose weight and reduced their water content, suggesting disruption of "the water barrier". Death of stored product insects treated with Diatomaceous Earth decreased with increased r.h., due to reduced transpiration through the cuticle. High r.h. delays, or above 60% can prevent, the drying action of Diatomaceous Earth.

Payá J. - One of the best experts on this subject based on the ideXlab platform.

  • Use of residual Diatomaceous Earth as a silica source in geopolymer production
    Materials Letters, 2018
    Co-Authors: Fo A., Soriano L., Reig Cerdá Lucía, Tashima M. M., Orrachero M., Monzó J., Payá J.
    Abstract:

    The use of binders as an alternative to Portland cement has gained importance in recent years. Among them, geopolymeric binders, developed by the reaction between an aluminosilicate precursor and a high alkalinity solution, have become one of the most promising alternatives. The activating solution generally comprises waterglass and sodium hydroxide. Since waterglass is the most expensive material and has a high environmental impact, using alternative silica sources will lead to more sustainable binders. Previous studies have successfully used rice husk ash (RHA) as a silica source. This research aims to assess the possibility of using Diatomaceous Earth (or diatomite) as an alternative silica source, like the previous studies with RHA. Diatomite is a sedimentary rock with a high amorphous silica content formed by fossilized diatom remains. In this work, the geopolymer was obtained using a fluid cracking catalyst residue as the precursor and six different activating solution types prepared with commercial products, residual diatomite (from beer and wine industries) and RHA. The results open a new possible route for the reuse and recovery of Diatomaceous Earth residue, although the compressive strength results of the mortars were slightly lower than those for mortars prepared with RHA or commercial reagents.