Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Mechanical properties of nanocrystalline materials

http://www.uniroma2.it/didattica/tbs2/deposito/Manufacture,_characterisation_and_application_of_cellular_metals_and_metal_foams.pdf

Manufacture, characterisation and application of cellular metals and metal foams

There have been a number of review papers on layered silicate and carbon nanotube reinforced polymer nanocomposites, in which the fillers have high aspect ratios. Particulate–polymer nanocomposites containing fillers with small aspect ratios are also an important class of polymer composites. However, they have been apparently overlooked. Thus, in this paper, detailed discussions on the effects of particle size, particle/matrix interface adhesion and particle loading on the stiffness, strength and toughness of such particulate–polymer composites are reviewed. To develop high performance particulate composites, it is necessary to have some basic understanding of the stiffening, strengthening and toughening mechanisms of these composites. A critical evaluation of published experimental results in comparison with theoretical models is given.

/pdf/effects-of-particle-size-particle-matrix-interface-adhesion-yv055zq7xi.pdf

Effects of particle size, particle/matrix interface adhesion and particle loading on mechanical properties of particulate–polymer composites

Below 1000°C the oxidation of nickel cannot be controlled by the diffusion of ions through the bulk crystal lattice of the pure oxide, because the measured oxidation rates are several orders of magnitude faster than would be predicted on this basis. Short-circuit diffusion through oxide grain boundaries or dislocations has usually been held responsible, but there has hitherto been no proper quantitative confirmation of this mechanism. We report measurements of the oxide scale thickness and oxide grain size as a function of time during the oxidation of high-purity nickel in the temperature range 500–800°C. All the oxidation experiments were carried out in pure oxygen at a pressure of one atmosphere. The measured parabolic oxidation rate constants have been compared with those calculated from grain boundary diffusion data obtained in our previous work, using a grain boundary diffusion model for the oxidation process. The quantitative agreement between measured and calculated oxidation rates shows c...

A quantitative demonstration of the grain boundary diffusion mechanism for the oxidation of metals

A model of ductile fracture based on the nucleation and growth of voids

The structure and properties of drawn pearlite

Structure and mechanical properties of Cu-X (X = Nb,Cr,Ni) nanolayered composites

The nucleation of precipitates: The system Al-Zn-Mg

Internal stresses in tension and compression in an extruded and artificially aged Mg-7.7at.% Al alloy have been determined by in-situ neutron diffraction. Measurements were made on grains having the c axis normal to, parallel to and at 62° from the stress axis, and on the reinforcing phase. The results are consistent with basal slip and {1012} twinning. The second-phase particles of Mg17Al12 bear much higher stresses than the magnesium matrix does. A simple mean stress model proposed by Brown and Clarke is shown to describe adequately the strengthening due to the particles. Twinning manifests itself clearly through variations in the integrated intensity of diffraction peaks during loading. Most of the observed variations in scattered peak intensity can be explained by referring to the lattice reorientation produced by {1012} twinning. The calculated stress tensors corresponding to these intensity variations have been used to show that a critical resolved shear stress criterion is applicable for {...

J.D. Embury

Papers

A model of ductile fracture based on the nucleation and growth of voids

The structure and properties of drawn pearlite

Structure and mechanical properties of Cu-X (X = Nb,Cr,Ni) nanolayered composites

The nucleation of precipitates: The system Al-Zn-Mg

Study of the mechanical properties of Mg-7.7at.% Al by in-situ neutron diffraction