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  • Wiley  (29)
  • Kawamoto, Ken  (29)
  • Englisch  (29)
  • 1
    Online-Ressource
    Online-Ressource
    Gas Transport Parameters in the Vadose Zone: Gas Diffusivity in Field and Lysimeter Soil Profiles
    Wiley ; 2006
    In:  Vadose Zone Journal Vol. 5, No. 4 ( 2006-11), p. 1194-1204
    Details
    In: Vadose Zone Journal, Wiley, Vol. 5, No. 4 ( 2006-11), p. 1194-1204
    Kurzfassung: The main soil‐gas transport parameters, gas diffusivity and air permeability, and their variations with soil type and air‐filled porosity play a key role in soil‐gas emission problems including volatilization of toxic chemicals at polluted sites and the production and emission of greenhouse gases. Only limited information on soil‐gas transport parameters across the vadose zone is available, especially for soil layers below the root zone. In a series of studies, we developed new data for the soil‐gas transport parameters in different soil profiles and tested existing and new predictive models. In this first study, we measured gas diffusivity at different soil‐water matric potentials on undisturbed soil samples for three lysimeter soil profiles down to 1.4‐m depth and for two field soil profiles down to 5.6‐m depth, representing a total of 22 different soil layers with soil texture ranging from sand to sandy clay loam. Five commonly used predictive gas diffusivity models were tested. The three‐porosity model (TPM) performed best for both shallow and deep soil layers. The tortuosity–connectivity parameter X in the TPM varied with soil texture and pore size distribution, and the TPM predicted well the depth distributions of measured soil‐gas diffusivities. The TPM also requires less detailed information on the soil‐water characteristic curve than other well‐performing predictive models, and is therefore recommended for predicting variations in soil‐gas diffusivity within the vadose zone.
    Materialart: Online-Ressource
    ISSN: 1539-1663 , 1539-1663
    URL: Article
    DOI: 10.2136/vzj2006.0014
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2006
    ZDB Id: 2088189-7
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Online-Ressource
    Open Access Wunsch
    Verfügbarkeit (elektronisch / print)
    BTU Cottbus
    Wissenschaftspark Albert Einstein
    EUV Frankfurt
    TH Wildau
    FH Potsdam
  • 2
    Online-Ressource
    Online-Ressource
    Two-Region Extended Archie's Law Model for Soil Air Permeability and Gas Diffusivity
    Wiley ; 2011
    In:  Soil Science Society of America Journal Vol. 75, No. 3 ( 2011-05), p. 795-806
    Details
    In: Soil Science Society of America Journal, Wiley, Vol. 75, No. 3 ( 2011-05), p. 795-806
    Materialart: Online-Ressource
    ISSN: 0361-5995
    URL: Article
    DOI: 10.2136/sssaj2010.0207
    RVK:
    RA 4845
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2011
    ZDB Id: 241415-6
    ZDB Id: 2239747-4
    ZDB Id: 196788-5
    ZDB Id: 1481691-X
    SSG: 13
    SSG: 21
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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    Online-Ressource
    Open Access Wunsch
    Verfügbarkeit (elektronisch / print)
    BTU Cottbus
    Wissenschaftspark Albert Einstein
    EUV Frankfurt
    TH Wildau
    FH Potsdam
  • 3
    Online-Ressource
    Online-Ressource
    Diffusion Aspects of Designing Porous Growth Media for Earth and Space
    Wiley ; 2012
    In:  Soil Science Society of America Journal Vol. 76, No. 5 ( 2012-09), p. 1564-1578
    Details
    In: Soil Science Society of America Journal, Wiley, Vol. 76, No. 5 ( 2012-09), p. 1564-1578
    Materialart: Online-Ressource
    ISSN: 0361-5995
    URL: Article
    DOI: 10.2136/sssaj2011.0438
    RVK:
    RA 4845
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2012
    ZDB Id: 241415-6
    ZDB Id: 2239747-4
    ZDB Id: 196788-5
    ZDB Id: 1481691-X
    SSG: 13
    SSG: 21
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Online-Ressource
    Open Access Wunsch
    Verfügbarkeit (elektronisch / print)
    BTU Cottbus
    Wissenschaftspark Albert Einstein
    EUV Frankfurt
    TH Wildau
    FH Potsdam
  • 4
    Online-Ressource
    Online-Ressource
    Generalized Density‐Corrected Model for Gas Diffusivity in Variably Saturated Soils
    Wiley ; 2011
    In:  Soil Science Society of America Journal Vol. 75, No. 4 ( 2011-07), p. 1315-1329
    Details
    In: Soil Science Society of America Journal, Wiley, Vol. 75, No. 4 ( 2011-07), p. 1315-1329
    Kurzfassung: Accurate predictions of the soil‐gas diffusivity ( D p / D o , where D p is the soil‐gas diffusion coefficient and D o is the diffusion coefficient in free air) from easily measureable parameters like air‐filled porosity (ε) and soil total porosity (ϕ) are valuable when predicting soil aeration and the emission of greenhouse gases and gaseous‐phase contaminants from soils. Soil type (texture) and soil density (compaction) are two key factors controlling gas diffusivity in soils. We extended a recently presented density‐corrected D p (ε)/ D o model by letting both model parameters (α and β) be interdependent and also functions of ϕ. The extension was based on literature measurements on Dutch and Danish soils ranging from sand to peat. The parameter α showed a promising linear relation to total porosity, while β also varied with α following a weak linear relation. The thus generalized density‐corrected (GDC) model gave improved predictions of diffusivity across a wide range of soil types and density levels when tested against two independent data sets (total of 280 undisturbed soils or soil layers) representing Danish soil profile data (0–8 m below the ground surface) and performed better than existing models. The GDC model was further extended to describe two‐region (bimodal) soils and could describe and predict D p / D o well for both different soil aggregate size fractions and variably compacted volcanic ash soils. A possible use of the new GDC model is engineering applications such as the design of highly compacted landfill site caps.
    Materialart: Online-Ressource
    ISSN: 0361-5995 , 1435-0661
    URL: Article
    DOI: 10.2136/sssaj2010.0405
    RVK:
    RA 4845
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2011
    ZDB Id: 241415-6
    ZDB Id: 2239747-4
    ZDB Id: 196788-5
    ZDB Id: 1481691-X
    SSG: 13
    SSG: 21
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Online-Ressource
    Open Access Wunsch
    Verfügbarkeit (elektronisch / print)
    BTU Cottbus
    Wissenschaftspark Albert Einstein
    EUV Frankfurt
    TH Wildau
    FH Potsdam
  • 5
    Online-Ressource
    Online-Ressource
    Density‐Corrected Models for Gas Diffusivity and Air Permeability in Unsaturated Soil
    Wiley ; 2011
    In:  Vadose Zone Journal Vol. 10, No. 1 ( 2011-02), p. 226-238
    Details
    In: Vadose Zone Journal, Wiley, Vol. 10, No. 1 ( 2011-02), p. 226-238
    Kurzfassung: Accurate prediction of gas diffusivity ( D p / D o ) and air permeability ( k a ) and their variations with air‐filled porosity (ε) in soil is critical for simulating subsurface migration and emission of climate gases and organic vapors. Gas diffusivity and air permeability measurements from Danish soil profile data (total of 150 undisturbed soil samples) were used to investigate soil type and density effects on the gas transport parameters and for model development. The measurements were within a given range of matric potentials (−10 to −500 cm H 2 O) typically representing natural field conditions in subsurface soil. The data were regrouped into four categories based on compaction (total porosity Φ 〈 0.4 or 〉 0.4 m 3 m −3 ) and soil texture (volume‐based content of clay, silt, and organic matter 〈 15 or 〉 15%). The results suggested that soil compaction more than soil type was the major control on gas diffusivity and to some extent also on air permeability. We developed a density‐corrected (D‐C) D p (ε)/ D o model as a generalized form of a previous model for D p / D o at −100 cm H 2 O of matric potential ( D p , 100 / D o ). The D‐C model performed well across soil types and density levels compared with existing models. Also, a power‐law k a model with exponent 1.5 (derived from analogy with a previous gas diffusivity model) used in combination with the D‐C approach for k a,100 (reference point) seemed promising for k a (ε) predictions, with good accuracy and minimum parameter requirements. Finally, the new D‐C model concept for gas diffusivity was extended to bimodal (aggregated) media and performed well against data for uncompacted and compacted volcanic ash soil.
    Materialart: Online-Ressource
    ISSN: 1539-1663 , 1539-1663
    URL: Article
    DOI: 10.2136/vzj2009.0137
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2011
    ZDB Id: 2088189-7
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Online-Ressource
    Open Access Wunsch
    Verfügbarkeit (elektronisch / print)
    BTU Cottbus
    Wissenschaftspark Albert Einstein
    EUV Frankfurt
    TH Wildau
    FH Potsdam
  • 6
    Online-Ressource
    Online-Ressource
    Variable Pore Connectivity Model Linking Gas Diffusivity and Air‐Phase Tortuosity to Soil Matric Potential
    Wiley ; 2012
    In:  Vadose Zone Journal Vol. 11, No. 1 ( 2012-02)
    Details
    In: Vadose Zone Journal, Wiley, Vol. 11, No. 1 ( 2012-02)
    Kurzfassung: Soil‐gas diffusivity ( D p / D o ) and its dependency on soil matric potential (ψ) is important when taking regulative measures (based on accurate predictions) for climate gas emissions and also risk‐mitigating measures (based on upper‐limit predictions) of gaseous‐phase contaminant emissions. Useful information on soil functional pore structure, e.g., pore network tortuosity and connectivity, can also be revealed from D p / D o –ψ relations. Based on D p / D o measurements in a wide range of soil types across geographically remote vadose zone profiles, this study analyzed pore connectivity for the development of a variable pore connectivity factor, X , as a function of soil matric potential, expressed as pF (=log |−ψ|), for pF values ranging from 1.0 to 3.5. The new model takes the form of X = X * ( F / F *) A with F = 1 + pF −1 , where X * is the pore network tortuosity at reference F ( F* ) and A is a model parameter that accounts for water blockage. The X –pF relation can be linked to drained pore size to explain the lower probability of the larger but far fewer air‐filled pores at lower pF effectively interconnecting and promoting gas diffusion. The model with X* = 2 and A = 0.5 proved promising for generalizing D p / D o predictions across soils of wide geographic contrast and yielded results comparable to those from widely used predictive models. The X –pF model additionally proved valuable for differentiating between soils (providing a unique soil structural fingerprint for each soil layer) and also between the inter‐ and intraaggregate pore regions of aggregated soils. We further suggest that the new model with parameter values of X * = 1.7 and A = 0 may be used for upper limit D p / D o predictions in risk assessments of, e.g., fluxes of toxic volatile organics from soil to indoor air at polluted soil sites.
    Materialart: Online-Ressource
    ISSN: 1539-1663 , 1539-1663
    URL: Article
    DOI: 10.2136/vzj2011.0096
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2012
    ZDB Id: 2088189-7
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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    Online-Ressource
    Open Access Wunsch
    Verfügbarkeit (elektronisch / print)
    BTU Cottbus
    Wissenschaftspark Albert Einstein
    EUV Frankfurt
    TH Wildau
    FH Potsdam
  • 7
    Online-Ressource
    Online-Ressource
    Gas Transport Parameters in the Vadose Zone: Development and Tests of Power‐Law Models for Air Permeability
    Wiley ; 2006
    In:  Vadose Zone Journal Vol. 5, No. 4 ( 2006-11), p. 1205-1215
    Details
    In: Vadose Zone Journal, Wiley, Vol. 5, No. 4 ( 2006-11), p. 1205-1215
    Kurzfassung: The soil‐air permeability ( k a ) and its dependency on air‐filled porosity (ε) govern convective air and gas transport in soil. For example, accurate prediction of k a (ε) is a prerequisite for optimizing soil vapor extraction systems for cleanup of soils polluted with volatile organic chemicals. In this study, we measured k a at different soil‐water matric potentials down to 5.6‐m depth, totaling 25 differently textured soil layers. Comparing k a and soil‐gas diffusivity ( D p / D 0 ) measurements on the same soil samples suggested an analogy between how the two soil‐gas transport parameters depend on ε. The exponent in a power‐law model for k a (ε) was typically smaller than for D p (ε)/ D 0 , however, probably due to the influence of soil structure and large‐pore network being more pronounced for k a than for D p / D 0 In analogy to recent gas diffusivity models and in line with capillary tube models for unsaturated hydraulic conductivity, two power‐law k a (ε) models were suggested. One k a (ε) model is based on the Campbell pore‐size distribution parameter b and the other on the content of larger pores (ε 100 , corresponding to the air‐filled porosity at −100 cm H 2 O of soil‐water matric potential). Both new models require measured k a at −100 cm H 2 O ( k a,100 ) as a reference point to obtain reasonably accurate predictions. If k a,100 is not known, two expressions for predicting k a,100 from ε 100 were proposed but will cause at least one order of magnitude uncertainty in predicted k a The k a (ε) model based on only ε 100 performed well in the model tests and is recommended together with a similar model for gas diffusivity for predicting variations in soil‐gas transport parameters in the vadose zone.
    Materialart: Online-Ressource
    ISSN: 1539-1663 , 1539-1663
    URL: Article
    DOI: 10.2136/vzj2006.0030
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2006
    ZDB Id: 2088189-7
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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    Online-Ressource
    Open Access Wunsch
    Verfügbarkeit (elektronisch / print)
    BTU Cottbus
    Wissenschaftspark Albert Einstein
    EUV Frankfurt
    TH Wildau
    FH Potsdam
  • 8
    Online-Ressource
    Online-Ressource
    Variable Pore Connectivity Factor Model for Gas Diffusivity in Unsaturated, Aggregated Soil
    Wiley ; 2008
    In:  Vadose Zone Journal Vol. 7, No. 2 ( 2008-05), p. 397-405
    Details
    In: Vadose Zone Journal, Wiley, Vol. 7, No. 2 ( 2008-05), p. 397-405
    Kurzfassung: The soil gas diffusion coefficient ( D p ) and its variations with soil air content (ε) and soil water matric potential (ψ) control vadose zone transport and emissions of volatile organic chemicals and greenhouse gases. This study revisits the 1904 Buckingham power‐law model where D p is proportional to ε X , with X characterizing the tortuosity and connectivity of air‐filled pore space. One hundred years later, most models linking D p (ε) to soil water retention and pore size distribution still assume that the pore connectivity factor, X , is a constant for a given soil. We show that X varies strongly with both ε and matric potential [given as pF = log(−ψ, cm H 2 O)] for indivi dual soils ranging from undisturbed sand to aggregated volcanic ash soils (Andisols). For Andisols with bimodal pore size distribution, the X –pF function appears symmetrical. The minimum X value is typically around 2 and was observed close to ψ of −1000 cm H 2 O (pF 3) when interaggregate voids are drained. To link D p with bimodal pore size distribution, we coupled a two‐region van Genuchten soil water retention model with the Buckingham D p (ε) model, assuming X to vary symmetrically around a given pF. The coupled model well described D p as a function of both ε and ψ for both repacked and undisturbed Andisols and for other soil types. By merely using average values of the three constants in the proposed symmetrical X –pF expression, predictions of D p were better than with traditional models.
    Materialart: Online-Ressource
    ISSN: 1539-1663 , 1539-1663
    URL: Article
    DOI: 10.2136/vzj2007.0058
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2008
    ZDB Id: 2088189-7
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Online-Ressource
    Open Access Wunsch
    Verfügbarkeit (elektronisch / print)
    BTU Cottbus
    Wissenschaftspark Albert Einstein
    EUV Frankfurt
    TH Wildau
    FH Potsdam
  • 9
    Online-Ressource
    Online-Ressource
    The Solute Diffusion Coefficient in Variably Compacted, Unsaturated Volcanic Ash Soils
    Wiley ; 2009
    In:  Vadose Zone Journal Vol. 8, No. 4 ( 2009-11), p. 942-952
    Details
    In: Vadose Zone Journal, Wiley, Vol. 8, No. 4 ( 2009-11), p. 942-952
    Kurzfassung: The solute diffusion coefficient in soil ( D s ) and its dependency on the soil water content (θ), soil type, and compaction govern the transport and fate of dissolved chemicals in the soil vadose zone. Only a few studies have quantified solute diffusivity ( D s / D 0 , where D s and D 0 are the solute diffusion coefficients in soil and pure water, respectively) for variably compacted soils with different textures. We measured the D s for KCl on five different soils from Japan: two volcanic ash soils (Andisols) at different bulk densities, two sandy soils, and a loamy soil. The D s was measured across a wide range of θ using the half‐cell method. The D s / D 0 values for Andisols with bimodal pore size distribution were comparatively lower than for the other soils. Opposite to the behavior for sandy soils, the D s / D 0 for Andisols at a given θ decreased markedly with increasing bulk density under wet conditions but increased with increasing bulk density under dry conditions. Data for all soil types including sandy soils with unimodal pore size distribution implied a two‐region behavior when plotted as log( D s / D 0 ) vs. θ. We suggest that the similar behavior across soil types can be explained by regions of low and high water phase connectivity for relatively structureless soils and by high intraaggregate and low interaggregate water phase tortuosity for aggregated soils. Among a number of tested predictive models for D s / D 0 , the Penman–Millington–Quirk model, which requires knowledge of only θ and total porosity, performed best across soil types.
    Materialart: Online-Ressource
    ISSN: 1539-1663 , 1539-1663
    URL: Article
    DOI: 10.2136/vzj2008.0184
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2009
    ZDB Id: 2088189-7
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Online-Ressource
    Open Access Wunsch
    Verfügbarkeit (elektronisch / print)
    BTU Cottbus
    Wissenschaftspark Albert Einstein
    EUV Frankfurt
    TH Wildau
    FH Potsdam
  • 10
    Online-Ressource
    Online-Ressource
    Unified Measurement System for the Gas Dispersion Coefficient, Air Permeability, and Gas Diffusion Coefficient in Variably Saturated Soil
    Wiley ; 2009
    In:  Soil Science Society of America Journal Vol. 73, No. 6 ( 2009-11), p. 1921-1930
    Details
    In: Soil Science Society of America Journal, Wiley, Vol. 73, No. 6 ( 2009-11), p. 1921-1930
    Kurzfassung: The transport of gaseous compounds in soil takes place by gas diffusion, advection, and dispersion. Gas transport processes are influenced by the soil‐gas diffusion coefficient ( D p ), air permeability ( k a ) and soil‐gas dispersion coefficient ( D H ), respectively. Of three gas transport parameters, D H is the least understood, especially how it is correlated to soil type, moisture conditions, and other transport parameters (i.e., D p and k a ). In this study, a unified measurement system (UMS) that enables sequential measurement of D p , k a , and D H on the same soil core was developed. The experimental sequence is based on a two‐chamber measurement of D H and k a , followed by a one‐chamber measurement of D p Gaseous oxygen concentration and air pressure sensors are located in inlet and outlet chambers as well as at multiple points along the soil column. Using different particle‐size fractions of non‐aggregated (Toyoura sand) and aggregated (Nishi‐Tokyo loam) soils, the effects of soil structure, particle (aggregate) size, and column scale (5‐cm i.d. and 30‐cm or 60‐cm length) on the three gas transport parameters were investigated. For both soils, D H linearly increased with increasing pore‐air velocity. For Toyoura sand, gas dispersivity (λ = D H / u 0 ) decreased with increasing soil‐air content, while for Nishi‐Tokyo loam, gas dispersivity decreased with increasing soil‐air content to a minimum value when inter‐aggregate pores were drained and increased again when the pores inside the soil aggregates started to act as tortuous air‐filled pathways. In the arterial pore region (corresponding to the total pore volume for Narita sand and the inter‐aggregate pore volume for Nishi‐Tokyo loam), a linear relation between tortuosity of the air‐filled pore network ( T , calculated from D p ) and the gas dispersivity (λ) was observed.
    Materialart: Online-Ressource
    ISSN: 0361-5995 , 1435-0661
    URL: Article
    DOI: 10.2136/sssaj2009.0012
    RVK:
    RA 4845
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2009
    ZDB Id: 241415-6
    ZDB Id: 2239747-4
    ZDB Id: 196788-5
    ZDB Id: 1481691-X
    SSG: 13
    SSG: 21
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Online-Ressource
    Open Access Wunsch
    Verfügbarkeit (elektronisch / print)
    BTU Cottbus
    Wissenschaftspark Albert Einstein
    EUV Frankfurt
    TH Wildau
    FH Potsdam
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