Thesis (Ph.D.)--Aberdeen University, 2009. / Title from web page (viewed on Mar. 3, 2010). Includes bibliographical references.

Thesis (M.Phil.) - University of Queensland, 2005. / Includes bibliography.

Thesis (Ph. D.)--Columbia University, 1940. / Published also as Bulletin no. 7, Dept of civil engineering, Columbia university, 1940. Vita. Bibliography: p. 39.

Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 73-90.

Thesis (M.S.)--Brigham Young University. Dept. of Civil and Environmental Engineering, 2006. / Includes bibliographical references (p. 163-166).

University, Diss., 2003--Bonn. / Erscheinungsjahr an der Haupttitelstelle: 2003.

Th. 3e cycle--Lett. mod.--Paris 12, [ca 1978].

The effect of sand mining on model groups of organisms (vascluar plants, beetles, amphibians and birds) was studied in South Bohemia. The studies were made in the next biotopes by model area sand pit Roudná II southern from Planá nad Lužnicí: unforested area (after mining), forest (on recultivated plots and seminatural forest) and water biotopes (depressions after mining). The next characteristics of biodiversity were determined: the diversity of communites, the frequency of protected, rare and vulnerable species. The protected species occur mainly in amphibians and birds. The suitable recultivation measures were proposed on the base of biodiversity studies.

The Seringveld Conservancy is situated near Cullinan in an area is that is characterised by deep sandy soils. Sand mining for the building industry has become a major threat to the biodiversity of the area. The flora of the Conservancy is best described as a gradual ecotone between the grassland and savanna biomes. The fist objective of the study is to describe the vegetation of the Seringveld Conservancy, in terms of plant communities, plant species composition, habitat as well as composing a vegetation map of the area. The second objective of the study is more theoretical and is aimed at providing a definition for savannas as well as shedding light on the complexity of South African savannas and there underlying driving forces. The Braun-Blanquet approach was used for sampling and 125 relevés were compiled. The data was captured using TURBOVEG and data analysis followed in JUICE 7.0. A total of 376 species was recorded in the area. Analysis from JUICE resulted in a TWINSPAN dendogram, synoptic table and two phytosociological tables. The phytosociological tables obtained from JUICE were refined using Braun-Blanquet procedures. Ten main plant communities and two sub-communities were identified. Each plant community was described in terms of species composition, dominant species and diagnostic species, and ecologically interpreted in terms of habitat characteristics. The plant communities were also compared to communities found in other studies in close proximity of the Seringveld i.e. Ezemvelo Nature Reserve. ArcGIS was used to create various maps further highlighting the uniqueness of the area. A vegetation map indicating the distribution of the plant communities was compiled. The combined results of the phytosociological tables as well as the GIS maps indicate that the Seringveld Conservancy is a complex area containing high biodiversity. Trying to define savanna is related to scale. The study area is considered to be savanna at local scale, this study will refer to savanna as a vegetation type with a well developed grassy layer and an upper layer of woody plants, which can vary from widely spaced to 75 percent tree cover. There is a gradient present between equilibrium and non-equilibrium dynamics in savanna ecosystems of southern Africa. / Dissertation (MSc)--University of Pretoria, 2010. / Plant Science / unrestricted

Particulate, discrete and frictional systems such as sand constitute a separate class of materials. In order to derive stress-strain relations for these materials, their key features have to be identified and incorporated into the theoretical formulations. The presence of voids, the ability to undergo continuous and systematic spatial rearrangement of particles, the existence of bounds for the developed ratio of tangent and normal contact forces and the systematic variations of the tangent and normal contact force distributions during general loading, are identified as key features of particulate, discrete and frictional systems. The contact normal and the contact branch length distribution functions describe the spatial arrangement of particles mathematically. The distribution of contact normals exhibit mutually orthogonal principal directions which coincide with the principal stress directions. Most contacts in frictional systems do not develop limiting friction during general loading. Sliding of a few suitably oriented contacts followed by rolling and rigid body rotations and displacements of a large number of particles is the main mechanism causing non-recoverable deformations in frictional systems. As a part of the rearranging process, dominant chains of particles are continuously constructed and destructed, the rates being different at different stages of loading. A change of loading direction is associated with a change of dominant chains of particles resulting in changes in strain magnitudes. Rate insensitive incremental stress-strain relations are derived here using the principle of virtual forces. The key features of frictional systems have been incorporated into the stress-strain relations following the theoretical framework proposed by Rothenburg(1980), for analysing bonded systems of uniform spherical particles. For frictional systems, the load-deformation response at particle contacts is assumed to be non-linear. The deformations resulting from all internal activity are quantified defining equivalent incrementally elastic stiffnesses in the tangent and normal directions at contacts and defining loading and unloading criteria. After each increment of loading, the incremental stiffnesses and contact normal distribution are updated to account for the changes resulting from rearrangement of particles. Laws that describe the spatial rearrangement of particles, changes in the ratio between the tangent and normal contact force distributions and the resistance to deformation resulting from changes in dominant chains of particles are established based on the information from laboratory experiments reported in the literature and numerical experiments of Bathurst(1985). The stress ratio and the state parameter (defined as the ratio of void ratios at the critical-state to the current state, computed for a given mean-normal stress) are identified as key variables that can be used to quantify the extent of particle rearrangements. The proposed formulations are capable of modelling the non-linear stress-strain response which is dependent on the inherent anisotropy, stress induced anisotropy, density of packing, stress level and stress path. To predict the stress-strain response of sand, a total of 24 model parameters have to be evaluated. All the model parameters can be evaluated from five conventional triaxial compression tests. The proposed stress-strain relations have been verified by comparing with laboratory measurements on sand. The data base consists of triaxial tests reported by Negussey(1984), hollow cylinder tests graciously carried out for the author by A. Sayao, and true triaxial and hollow cylinder tests made available for the Cleveland Workshop(1987). / Applied Science, Faculty of / Civil Engineering, Department of / Graduate