3,392 research outputs found
Voyage of the Northern Light : newspaper reports and articles.
No full textCover title.; For private circulation only.; Contains typescript copy of a letter from the author to the Daily telegraph.; Library's N copy is inscribed "To the Editor Bulletin, Joshua Slocum ... Strictly private". ANL; Electronic reproduction. Canberra, A.C.T. : National Library of Australia, 2009
Joshua Davis: Author of Spare Parts
No full textCitation: K-State First (2016). Joshua Davis: Author of Spare Parts [Flier]. Manhattan, Kansas: K-State First.Flyer advertising Joshua Davis's author talk at Kansas State University
Summary of Advances in Heat-Pulse Methods: Measuring Near-Surface Soil Water Content
No full textSurface layer soil water content is important for evaporation, surface energy balance, seed germination, residue decomposition, microbial activity, and many other biological, chemical, and physical processes. The standard method (i.e., the gravimetric method) for measuring soil water content requires destructive sampling and is unsuitable for continuous measurement. Techniques such as neutron thermalization and time domain reflectometry suffer relatively large errors in measuring soil water content near the surface. In a recent Methods of Soil Analysis article, the authors present the principles and procedures for using a heat-pulse sensor to determine near-surface soil water content.This article is published as Zhang, Xiao, Tusheng Ren, Joshua Heitman, and Robert Horton. "Summary of Advances in Heat-Pulse Methods: Measuring Near-Surface Soil Water Content." Soil Science Society of America Journal 82, no. 5 (2018): 1015. doi: 10.2136/sssaj2018.04.0138.</p
Indigeous author talk
No full textA unique online author event celebrating the diversity of literature created by and for Two-Spirit and Indigiqueer people. This event features writers and creators T’áncháy Redvers and Joshua Whitehead in conversation with host Taya Jardine.Other UBCNon UBCUnreviewedOthe
Robust calibration and evaluation of a percolation-based effective‐medium approximation model for thermal conductivity of unsaturated soils
No full textThermal conductivity (λ) is a property characterizing heat transfer in porous media, such as soils and rocks, with broad applications to geothermal systems and aquifer characterizations. Numerous empirical and physically-based models have been developed for thermal conductivity in unsaturated soils. Recently, Ghanbarian and Daigle (G&D) proposed a theoretical model using the percolation-based effective-medium approximation. An explicit form of the G&D model relating λ to water content (θ) and equations to estimate the model parameters were also derived. In this study, we calibrated the G&D model and two widely applied empirical λ(θ) models using a robust calibration dataset of 41 soils. All three λ(θ) model performances were evaluated using a validation dataset of 58 soils. After calibration, the root mean square error (RMSE), mean absolute error (MAE) and coefficient of determination (R2) of the G&D model were 0.092 W−1 m−1 K−1, 0.067 W−1 m−1 K−1 and 0.97, respectively. For the two empirical models, RMSEs ranged from 0.086 to 0.096 W−1 m−1 K−1, MAEs from 0.063 to 0.071 W−1 m−1 K−1, and R2 values were about 0.97. All three metrics indicated that calibration improved the performance of the G&D model, and it had an accuracy similar to that of the two empirical λ(θ) models. Such a robust performance confirmed that the theoretically-based G&D model can be applied to study soil heat transfer and potentially other related fields.This article is published as Fu, Yongwei, Behzad Ghanbarian, Robert Horton, and Joshua Heitman. "Robust calibration and evaluation of a percolation-based effective‐medium approximation model for thermal conductivity of unsaturated soils." Geoderma 438 (2023): 116631. doi:10.1016/j.geoderma.2023.116631. © 2023 The Author(s).This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Estimating thermal conductivity of frozen soils from air‐filled porosity
No full textSoil thermal conductivity (λ) is an important thermal property for environmental, agricultural, and engineering heat transfer applications. Existing λ models for frozen soils are complicated to use because they require estimates of both liquid water content and ice content. This study introduces a new approach to estimate λ of partially frozen soils from air‐filled porosity (n a), which can be determined by using an oven‐drying method. A λ and n a relationship was established based on measurements for 28 partially frozen soils. A strong exponential relationship between λ and n a was found (with R2 of 0.82). Independent tests on 10 partially frozen soils showed that the exponential λ‐n a model produced reliable λ estimates with a RMSE of 0.319 W m−1 K−1, which was smaller than those of two widely used λ models for partially frozen soils. The λ‐n a model is easier to use than existing models, because it requires fewer parameters. Note that the λ‐n a model ignores the effect of temperature on λ of frozen soils and is most applicable to soil at temperatures ≤ ‐4°C.This is a manuscript of an article published as Tian, Zhengchao, Tusheng Ren, Joshua L. Heitman, and Robert Horton. "Estimating thermal conductivity of frozen soils from air‐filled porosity." Soil Science Society of America Journal (2020). doi: 10.1002/saj2.20102. Posted with permission.</p
Hebrew made easy [electronic resource] : or, a brief introduction to the Hebrew grammar, (upon a new and delightful plan); Whereby our British Gentlemen and Ladies may, in so very short a Time as Twenty-Four Days, learn the most necessary and essential Variations of that incomparable Language, without the Help of the Latin, or the Assistance of a Master. The second edition, with additions. By the author of The great importance of the Hebrew language.
No full textThe author of "The great importance of the Hebrew language" = Joshua Kettilby.Kettilby's 'Hebrew made easy' was first published in [1760?] (c.f.t123545). 'The excellency and great importance of the Hebrew language ... by Joshua Kettilby, author of Hebrew made easy' was published in 1762 (c.f.t183663)Electronic reproduction.English Short Title Catalog,Reproduction of original from Bodleian Library (Oxford)
Surface Shading, Soil Temperature, and Soil Moisture Effects on C Loss in a Temperate Peatland
No full textTAGGART, MATTHEW. Surface Shading, Soil Temperature, and Soil Moisture Effects on Soil C Loss in a Temperate Peatland. (Under the direction of Joshua Heitman).
Histosols are a huge reservoir for C, covering < 1% of the world‟s land surface but holding up to 12% of total soil C. Thorough comprehension of factors controlling the rate of soil C loss from peatlands is critical for proper management of these C sinks. Three experiments evaluated how formerly cultivated, warm climate Histosols undergoing restoration efforts might respond to increasing water content via water table re-establishment and decreases in soil temperatures via vegetative shading. We compared temperature and soil CO2 efflux differences from intact soil cores, collected from Juniper bay, under three levels of light reduction in a greenhouse: 0%, 70%, and 90%. Soil in full sun was consistently warmer and showed higher efflux rates than 70% and 90% shade treatments: 4.132, 3.438, and 2.054 μmol CO2 m-2 s-1, respectively. Shade treatments reached peak efflux rates at similar water potential, -2 to -4 kPa. A field experiment at Juniper bay subjected in-situ soil to full sun, 70% light reduction, and light reduction from naturally occurring herbaceous vegetation. Shade treatment effects on soil temperature and C mineralization were evident throughout the growing season. Vegetation shade effects on soil temperature were greatest in August and September when soil under vegetation was 5°-11°C cooler than unshaded soil. Soil CO2 efflux was correlated strongly with soil temperature; daily efflux rates were consistently highest from unshaded soil. Efflux across treatments showed a strong seasonal correlation to soil moisture, increasing as soil dried in response to water table decline. Soil water potential was unaffected by shade treatment, suggesting temperature effects were solely responsible for efflux differences between treatments. C mineralization response to temperature and moisture was verified with lab incubations of soil material at 25° and 37°C for three moisture ranges. Incubation showed a temperature/moisture interaction where Q10 was 2.55 under wet soil conditions (0.40 m3 m-3) and 1.64 when soil was driest (0.15-0.16 m3 m-3). All results confirm surface shading has a
strong influence on soil temperatures and C mineralization rates. Thoughtful management of vegetation in mitigated peatlands may be an effective strategy for slowing soil C losses and promoting soil C sequestration
Estimating soil water retention curves over the entire saturation range: A thermal conductivity-based approach
No full textThe relationship between soil water content (θ) and suction (h, referring to the absolute value of pressure head), is described by the soil water retention curve (SWRC). Our earlier research (Fu et al. (2021, 2023a) [J. Hydrol.127171]; [J. Hydrol.129898]) recognized underlying correlations between SWRCs and soil thermal conductivity (λ) versus θ curves, and developed methodologies to ascertain the parameters of the van Genuchten (vG) equation using λ(θ) measurements, described by the Ghanbarian & Daigle (GD) equation, and basic soil characteristics. Limitations intrinsic to the van Genuchten equation restrict the GD-vG approach to generate precise estimates only in the wet and medium suction range, specifically h ranging from 0 to 150 mH2O. The validity of these approaches in the dry region remains uncertain. In this study, we associated the Peters-
Durner-Iden (PDI) model parameters to those of the GD model. An initial examination was performed on the linearization processes needed to derive the hydraulic continuity water content (θhc) from the capillary water component as characterized by the PDI model and to choose the suction at oven dryness (h0) based on PDI model performance. Subsequently, two piecewise functions and two pedo-transfer functions were formulated to compute the PDI model parameters utilizing soil porosity, particle size distribution, and GD parameters, based on a calibration dataset comprising 25 different soils. The new GD-PDI approach was subsequently assessed with six independent soils and juxtaposed with the previous GD-vG approach. The GD-PDI approach outperformed the GD-vG approach, particularly within the dry range.This is a manuscript of an article published as Fu, Yongwei, Robert Horton, and Joshua Heitman. "Estimating soil water retention curves over the entire saturation range: A thermal conductivity-based approach." Journal of Hydrology (2024): 132138. doi:10.1016/j.jhydrol.2024.132138
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