3,869 research outputs found
Mineral acquisition from clay by Budongo Forest chimpanzees
No full textDate of Acceptance: 06/07/2015Chimpanzees of the Sonso community, Budongo Forest, Uganda were observed eating clay and drinking clay-water from waterholes. We show that clay, clay-rich water, and clay obtained with leaf sponges, provide a range of minerals in different concentrations. The presence of aluminium in the clay consumed indicates that it takes the form of kaolinite. We discuss the contribution of clay geophagy to the mineral intake of the Sonso chimpanzees and show that clay eaten using leaf sponges is particularly rich in minerals. We show that termite mound soil, also regularly consumed, is rich in minerals. We discuss the frequency of clay and termite soil geophagy in the context of the disappearance from Budongo Forest of a formerly rich source of minerals, the decaying pith of Raphia farinifera palms.Peer reviewe
Guide to the nature and methods of analysis of the clay fraction of tephras from the South Auckland region, New Zealand.
No full textThe manual outlines some of the more common laboratory procedures available for qualitatively and quantitatively analysing the composition of the tephric clays, many of which are difficult to determine because of their short range order or 'amorphous' nature. Techniques described and assessed in terms of their rapidity and quantitativeness include XRD, IR, DTA, TEM and SEM, sodium fluoride reactivity, chemical dissolution analyses, and surface area measurements. No one technique alone produces a definitive clay fraction analysis of tephric deposits. -from Author
Collective effects on the settling of clay flocs
No full textIn this work a high-magnification digital video camera in combination with a settling column is used to study in a first part the influence of the amount of flocs transferred into the settling column on their settling velocity. In a second part, the setup was used to study the properties of flocs prepared at different clay concentrations but at same flocculant to clay ratio (2.5mgg−1). Illite clay was used and flocculated in a 1 L jar with an anionic polyacrylamide (flocculant). Results show that the average settling velocity of flocs is a function of the amount of transferred flocs. It was also found that floc size and settling velocity depend on clay concentration. This is attributed to the fast aggregation happening in the jar when flocculant and clay are mixed: at higher clay concentrations, larger flocs are created in the first minutes of the experiment, with low densities that prevent them from settling to the bottom of the jar.Environmental Fluid MechanicsRivers, Ports, Waterways and Dredging Engineerin
Clay micromechanics: experimental challenges and perspectives
No full textThe importance of physico-chemical processes at the particle scale for the engineering scale behaviour of fine-grained geomaterials is undisputed. Yet, despite great advances in the discipline, experimental evidence that fully resolves the clay micromechanics i.e. linking the evolving microstructure and interparticle actions under loading, is lacking. This paper will discuss the challenges ahead in quantifying the evolving kinematics and interparticle interactions of finegrained geomaterials. As such, the current limitations, and the potential opportunities of experimental methodologies for manipulating, monitoring and (post-mortem) analysing fine-grained materials at the particle scale will be discussed. In addition to the need of integrating multiple experimental techniques that span several length scales and modalities, the critical role of advanced data reduction and analysis is highlighted, as required for a measurement as opposed to qualitative observation. Throughout the paper, the link between experimental clay micromechanics and modelling will be discussed.Geo-engineerin
Dredging Processes I: The Cutting of Sand, Clay & Rock - Theory
No full textThis book gives an overview of cutting theories. It starts with a generic model, which is valid for all types of soil (sand, clay and rock) after which the specifics of dry sand, water saturated sand, clay, rock and hyperbaric rock are covered. For each soil type small blade angles and large blade angles, resulting in a wedge in front of the blade, are discussed. The failure mechanism of sand, dry and water saturated, is the so called Shear Type. The failure mechanism of clay is the so called Flow Type, but under certain circumstances also the Curling Type and the Tear Type are possible. Rock will usually fail in a brittle way. This can be brittle tensile failure, the Tear Type, for small blade angles, but it can also be brittle shear failure, which is of the Shear Type of failure mechanism for larger blade angles. Under hyperbaric conditions rock may also fail in a more ductile way according to the Flow Type of failure mechanism. For each case considered, the equations/model for the cutting forces, power and specific energy are given. The models are verified with laboratory research, mainly at the Delft University of Technology, but also with data from literature.Marine & Transport TechnologyMechanical, Maritime and Materials Engineerin
Light D'Albergo Bailey
No full textPhotograph shows profile bust portrait of Light D'Albergo (Mrs. Clay) Bailey, teacher and author
Clement Claiborne Clay, Jr., letter and biographical sketch, MSS.0309
No full textAbstract: Letter written from Tuscaloosa in 1834, to his aunt, Mrs. Robert W. Withers of Erie, Greene County, Alabama, and a biographical sketch, author and date unknown, which includes information on Clay's political career, wedding, and friends.Scope and Content Note: The collection contains an 1834 letter written from Tuscaloosa to his aunt, Mrs. Robert W. Withers of Erie, Greene County, Alabama and a biographical sketch, author and date unknown, which includes information on Clay's political career, wedding, and friends.Biographical/Historical Note: Clement Claiborne Clay, Jr., the oldest son of former Alabama senator and governor, Clement Comer Clay, was born on 13 December 1816, in Huntsville, Alabama. He graduated from the University of Alabama in 1834 and from the law department of the University of Virginia at Charlottesville, in 1839. He was admitted to the bar in Alabama in 1840. He married Virginia Tunstall in 1843; the couple had several children.Clay was elected to the Alabama State House of Representatives in 1842, 1844, and 1845, and then served as a county judge in Madison County, Alabama from 1848 to 1850. He ran for a seat in the United States Congress in 1850 but was not elected. Later, in 1853, the Alabama legislature elected him to serve in the United States Senate in the term beginning on 4 March 1853. However, because of the legislature's delay in filling the position, he actually only took office on 29 November 1853, and served until 21 January 1861, when Alabama seceded from the Union at the beginning of the Civil War. He was subsequently elected by the Alabama Confederate legislature as Senator in the First Confederate Congress, where he served from 1862 until 1864.Although he declined the position of Confederate Secretary of War in Jefferson Davis' Cabinet, he and Jacob Thompson headed the Confederate secret agents. They had employed John Wilkes Booth for some services before Booth assassinated Abraham Lincoln, and due to suspicions that Clay was involved in an assassination plot, Clay and his wife were arrested and imprisoned in Fortress Monroe in Washington, DC, in 1865, where they were held for approximately one year.When the Clays were released, they returned to his plantation in Jackson County, Alabama, where he devoted himself to agricultural pursuits and to his law practice. Clement Claiborne Clay, Jr. died on 3 January 1882
Crushed rock and clay amelioration of a nutrient decifient, sandy soil of Maputaland
No full textBibliography: leaves 57-62.Various studies have suggested the possibility that food derived through subsistence agriculture in the Mseleni region of Maputaland contributes to malnutrition within the local community, particularfy within the high proportion of the population which suffers from a severe, disabling form of osteoarthritis. This study was conducted to determine if the application of local crushed rock or black clay to these nutrient deficient, sandy soils would increase available nutrient concentrations and improve the growth of plants in the ameliorated soil
Physico-Chemical Factors of Clay Particle Migration and Formation Damage
No full textThis article describes the effects of different physico-chemical factors on formation damage caused by migration of in situ clay particles as a result of water injection into a clastic reservoir.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Reservoir Engineerin
Quantitative and structural analysis of minerals in soil clay fractions developed under different climate zones in China by XRD with Rietveld method, and its implications for pedogenesis
No full textMineral compositions and structures in soil clay fractions can reflect the pedogenesis and the pedoenvironments of the natural soils. However, the simultaneous quantification and structural analysis of all phases in soils by X-ray diffraction are difficult, mainly due to overlapping reflections. In this study, quantification and structural analysis of the mineral phases in clay fractions in five soils (Alliti-Udic Ferrosol, Claypani-Udic Argosol, and Hapli-Udic Argosol, Malan loess, and Paleosol), developed under different climate zones in China, were carried out by the Rietveld method. Before proceeding with these analyses for the natural soil clay fractions by the Rietveld method, this method was applied to a set of artificial soils of montmorillonite (including a 6.8% quartz impurity), kaolinite, goethite, hematite, and magnetite to evaluate the accuracy of the method. Moreover, in the Rietveld method, the structure phase models, background function, profile models, the initial values for the correction of preferred orientation, and sequence of operations in Rietveld refinement parameters were optimized to improve the accuracy of the method. The evaluation demonstrated the quantitative analysis by the Rietveld method can obtain relatively satisfied results. The absolute errors for the mineral contents below 5% were in the range of - 0.49%- + 0.63%, and those for the mineral contents above 10% were in the range of - 6.32%-+ 5.00%. The absolute errors for the Al-substitutions in the goethite and hematite are - 0.8 Al mol %-+ 3.2 Al mol% and - 0.3 Al mol%-+ 3.3 Al mol%, respectively. Employing the above Rietveld method, the content of every mineral and Al-substituted iron (hydr)oxides (goethite and hematite) in the clay fractions in the five soils developed under different climate zones were obtained. In combined with the soil physicochemical properties, the order of pedogenic development of the five natural soils is Alliti-Udic Ferrosol > Claypani-Udic Argosol > Hapli-Udic Argosol and > Malan loess, respectively
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