There is a special reason for reviewing this book at this time: it is the 50th edition of a compendium that is known and used frequently in most chemical and physical laboratories in many parts of the world. Surely, a publication that has been published for 56 years, withstanding the vagaries of science in this century, must have had something to offer. There is another reason: while the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice). I believe that the Handbook can be useful in those laboratories. One of the reasons, among others, is that the various basic items of information it offers may be helpful in new tests, either physical or chemical, which are continuously being published. The basic information may relate

Handbook of Chemistry and Physics

An analytical method for developing a theoretical load-settlement curve for axially loaded piles in clay is presented. The method is based on the correlation of the ratio of load transfer to soil shear strength as a function of pile movement. The results of studies of field tests of instrumented piles and laboratory tests of small piles in clay are used to obtain the desired correlation. The correlation is presented in the form of a family of curves that are obtained when the ratios of load transfer to soil shear strength versus pile movement are plotted as a function of depth. The validity of the family of correlation curves is checked by comparing computed and actual load-settlement curves for some typical field tests. Results obtained by this method indicate that the method may be used effectively to determine load-carrying capacity for axially loaded piles in clay.

Closure to “Load Transfer for Axially Loaded Piles in Clay”

Gas hydrates have received considerable attention due to their important role in flow assurance for the oil and gas industry, their extensive natural occurrence on Earth and extraterrestrial planets, and their significant applications in sustainable technologies including but not limited to gas and energy storage, gas separation, and water desalination Given not only their inherent structural flexibility depending on the type of guest gas molecules and formation conditions, but also the synthetic effects of a wide range of chemical additives on their properties, these variabilities could be exploited to optimise the role of gas hydrates This includes increasing their industrial applications, understanding and utilising their role in Nature, identifying potential methods for safely extracting natural gases stored in naturally occurring hydrates within the Earth, and for developing green technologies This review summarizes the different properties of gas hydrates as well as their formation and dissociation kinetics and then reviews the fast-growing literature reporting their role and applications in the aforementioned fields, mainly concentrating on advances during the last decade Challenges, limitations, and future perspectives of each field are briefly discussed The overall objective of this review is to provide readers with an extensive overview of gas hydrates that we hope will stimulate further work on this riveting field

Gas hydrates in sustainable chemistry

Soil, through its various functions, plays a vital role in the Earth's ecosystems and provides multiple ecosystem services to humanity. Pedotransfer functions (PTFs) are simple to complex knowledge rules that relate available soil information to soil properties and variables that are needed to parameterize soil processes. In this paper, we review the existing PTFs and document the new generation of PTFs developed in the different disciplines of Earth system science. To meet the methodological challenges for a successful application in Earth system modeling, we emphasize that PTF development has to go hand in hand with suitable extrapolation and upscaling techniques such that the PTFs correctly represent the spatial heterogeneity of soils. PTFs should encompass the variability of the estimated soil property or process, in such a way that the estimation of parameters allows for validation and can also confidently provide for extrapolation and upscaling purposes capturing the spatial variation in soils. Most actively pursued recent developments are related to parameterizations of solute transport, heat exchange, soil respiration and organic carbon content, root density and vegetation water uptake. Further challenges are to be addressed in parameterization of soil erosivity and land use change impacts at multiple scales. We argue that a comprehensive set of PTFs can be applied throughout a wide range of disciplines of Earth system science, with emphasis on land surface models. Novel sensing techniques provide a true breakthrough for this, yet further improvements are necessary for methods to deal with uncertainty and to validate applications at global scale.

https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1002/2017RG000581

Pedotransfer functions in Earth system science: challenges and perspectives

A number of analyses, meta-analyses, and assessments, including those performed by the Intergovernmental Panel on Climate Change, the National Oceanic and Atmospheric Administration, the National Renewable Energy Laboratory, and the International Energy Agency, have concluded that deployment of a diverse portfolio of clean energy technologies makes a transition to a low-carbon-emission energy system both more feasible and less costly than other pathways. In contrast, Jacobson et al. [Jacobson MZ, Delucchi MA, Cameron MA, Frew BA (2015) Proc Natl Acad Sci USA 112(49):15060-15065] argue that it is feasible to provide "low-cost solutions to the grid reliability problem with 100% penetration of WWS [wind, water and solar power] across all energy sectors in the continental United States between 2050 and 2055", with only electricity and hydrogen as energy carriers. In this paper, we evaluate that study and find significant shortcomings in the analysis. In particular, we point out that this work used invalid modeling tools, contained modeling errors, and made implausible and inadequately supported assumptions. Policy makers should treat with caution any visions of a rapid, reliable, and low-cost transition to entire energy systems that relies almost exclusively on wind, solar, and hydroelectric power.

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Evaluation of a proposal for reliable low-cost grid power with 100% wind, water, and solar

Although it is well established that heat conduction in unsaturated soil depends on liquid saturation, there are several models available to consider the changes in thermal conductivity during drying and wetting. The key factors affecting thermal conductivity of unsaturated soil are evaluated through a critical examination of these different models and their development. Depending on the principles and assumptions employed, these models are categorized into three groups: mixing models involving series/parallel elements; empirical models where thermal conductivity values at dry and saturated states are used; and mathematical models based on phase volume fractions. Experimental data for different soils are used to assess the quality of prediction for these models. It is found that all the existing models do not realistically account for pore structure or interface properties, and thus are not capable of properly predicting thermal conductivity as a function of liquid saturation. A conceptual model based on soil–water retention mechanisms, is proposed to overcome the pitfalls of the existing models and can be used to establish quantitative thermal conductivity models for variably saturated soils in the future.

/pdf/critical-review-of-thermal-conductivity-models-for-32ba8ju8f5.pdf

Critical Review of Thermal Conductivity Models for Unsaturated Soils

Eight full-scale energy foundations were constructed for a new building at the US Air Force Academy. The foundations are being used to demonstrate this technology to the United States Department of Defense and have several experimental features in order to study their thermal–mechanical behavior. Three of the foundations are instrumented with strain gages and thermistors, and their thermo-mechanical response during a heating and cooling test was evaluated. For a temperature increase of 18 °C, the maximum thermal axial stress ranged from 4.0 to 5.1 MPa, which is approximately 25 % of the compressive strength of concrete (estimated at 21 MPa), and the maximum upward displacement ranged from 1.4 to 1.7 mm, which should not cause angular distortions sufficient enough to cause structural or aesthetic damage of the building. The end restraint provided by the building was observed to change depending on the location of the foundation. The heat flux per meter was measured by evaluating the temperatures and flow rates of a heat exchanger fluid entering and exiting the foundations. The heat flux values were consistent with those in the literature, and the foundation with the three continuous heat exchanger loops was found to have the greatest heat flux per meter. The transient thermal conductivity of the subsurface measured using the temperatures of the subsurface surrounding the foundation ranged from 2.0 to 2.3 W/mK, which is consistent with results from thermal response tests on energy foundations reported in the literature.

/pdf/evaluation-of-thermo-mechanical-and-thermal-behavior-of-full-1eal7xt8uv.pdf

Evaluation of thermo-mechanical and thermal behavior of full-scale energy foundations

This study presents a centrifuge modeling approach to characterize the transient thermomechanical response of energy foundations during heating-cooling cycles to provide data for calibration and validation of soil-structure interaction models. This study focuses on the response of a scale-model energy foundation installed in an unsaturated silt layer with end-bearing boundary conditions. The foundation response was assessed using embedded strain gauges and thermocouples. Other variables monitored include foundation head displacements, soil surface displacements, and changes in temperature and volumetric water content in the unsaturated silt at different depths and radial locations. Measurements during the initial heating process indicate that the thermal axial stress is greater near the toe of the foundation as a result of the restraint associated with mobilization of side shear resistance along the length of the foundation. The thermal axial strains were close to the free-expansion thermal strain...

/pdf/centrifuge-modeling-of-soil-structure-interaction-in-energy-26f0omemes.pdf

Centrifuge Modeling of Soil-Structure Interaction in Energy Foundations

This paper focuses on the response of two full-scale energy foundations beneath an 8-story building during operation of a heat pump over a 658-day period. During circulation of fluid having temperatures ranging from 7 to 35 °C through the closed-loop heat exchangers within the foundations, the temperature of the reinforced concrete ranged from 9 to 30 °C and was relatively uniform with depth. Estimates of the average heat exchange per unit meter ranged from 91 to 95 W/m. The thermal axial strains during the first year of heating and cooling were elastic and recoverable, but a change in mobilized coefficient of thermal expansion occurred in the second year, potentially due to changes in interface shear stresses. The smallest magnitudes of thermal axial strains were observed at the top and bottom of the foundations due to the restraint provided by the overlying building and underlying bedrock. Issues were encountered in the interpretation of the thermal axial stresses, and were attributed to thermally induced dragdown and transient differences in temperature between the reinforced concrete and sensors. The maximum thermo-mechanical axial stress in the foundations was approximately 10 MPa, well within structural limits. The mobilized side shear stresses follow a nonlinear profile with depth, potentially due to the combined effects of thermal expansion and downdrag. The thermal axial displacements estimated at the foundation head relative to the toe ranged from −1.5 upward to 0.8 mm downward during heating and cooling of the foundation, respectively, which are not expected to affect the building.

/pdf/seasonal-response-of-energy-foundations-during-building-1etvy5xu47.pdf

Seasonal Response of Energy Foundations During Building Operation

This paper focuses on the thermo-mechanical response of two full-scale energy foundations installed at the new Denver Housing Authority Senior Living Facility in Denver, Colorado. The energy foundations were formed by attaching heat exchanger tubes to the inside of the reinforcement cages of drilled shafts. The heat exchange tubes were connected to a ground-source heat pump system, which circulates a methanol-water mixture through the tubing to absorb or shed heat into the foundation and surrounding soil or rock. Instrumentation was incorporated to assess the heat exchange response of the foundations as well as the thermo-mechanical strains during construction and typical building operation. The temperature changes within the foundations are stable during heating and cooling operations and the corresponding thermal axial strains are within acceptable limits. The thermal axial strain profiles measured for both foundations follow trends expected for end-bearing boundary conditions with greater strains near the top of the foundations (upward expansion). The mobilized thermal expansion coefficients inferred from the instrumentation confirm that side shear stresses provide resistance to thermally induced movements. The results from this study indicate that energy foundations can be implemented in new buildings to gain improved heat exchange capabilities without major impacts on the foundation performance, for little added installation cost.

John S. McCartney

Papers

Critical Review of Thermal Conductivity Models for Unsaturated Soils

Evaluation of thermo-mechanical and thermal behavior of full-scale energy foundations

Centrifuge Modeling of Soil-Structure Interaction in Energy Foundations

Seasonal Response of Energy Foundations During Building Operation

Strain Distributions in Full-Scale Energy Foundations (DFI Young Professor Paper Competition 2012)