High Deformation Zone Research Articles

Superficial Grain Refinement of 316L Stainless Steel by Rolling with Rough Rolls.

This study presents a novel approach to producing superficial micro- and nanostructures using a cold rolling process with rough rolls, followed by low-temperature annealing. The proposed technique attempts to recreate the superficial deformation occurring in the sandblasting process. It allows for the generation of an inhomogeneous network, or tangle, of high-deformation zones on the material's surface that act as nucleation centers during the subsequent annealing process. However, the proposed method has a significant advantage over sandblasting: it is a continuous process with high productivity. An austenitic stainless-steel sheet, previously normalized, was used as the raw material. The samples were cold rolled using rough rolls (rhombic-based pyramids of 2.08 mm, 1.04 mm, and 1.5 mm in length, width, and height, respectively) and annealed at temperatures between 200 °C and 400 °C for one hour. An optical and electronic microstructure analysis showed the presence of small, heterogeneously distributed surface grains of 200-300 nm in diameter. Finite element analysis revealed significant deformation that was inhomogeneous and likely responsible for the uneven distribution of the recrystallized grains. Additionally, surface nanohardness results showed a 20% increase with respect to the central zone of the material. Finally, wear tests of the treated samples showed lower wear than samples rolled with conventional rolls.

The study of wind-interference effect on an elevated RC circular tank due to an adjacent building

Elevated water tanks are constructed to store and supply the water to a building (residential, official, commercial, institutional, etc.) or community, as per demand. Elevated tanks are vulnerable under wind loading, especially when empty. Due to the unavailability of proper and adequate literature on the effect of wind loading on reinforced concrete (RC) circular elevated tank, the present authors have taken up this issue for study. The effect of interference of wind on an elevated RC water tank with circular cross-section, caused by a building adjacent to that water tank, has been studied by performing fluid structure interaction (FSI) analyses. The along and across wind flow cases have been considered to understand the effect of wind directionality. The spacing between the elevated tank and the building, along with the height of interfering building have been varied. The wind pressure coefficient distribution and the deformation contour of the empty elevated tank for isolated and building-interference conditions have been calculated and compared. The concentration of wind-pressure (which is positive in nature) at windward region of principal elevated tank decreases with the decrease in proximity between the tank and the interfering building, for along wind flow condition. Due to the proximity of the interfering building, high deformation zone has been observed at the side region of the elevated principal tank, under the excitation of along wind flow. Also, the magnitude of the deformation of the elevated tank decreases with the decrease in the proximity of the interfering building from the tank, considering the along wind flow. In case of across wind flow, the high deformation zone can be observed at the windward region of the elevated principal tank. The elevated tank columns are observed to exhibit sway under the transverse effect of wind loading.

Implication of 40Ar/39Ar–petrochronology in the Buracão orogenic gold deposit for tectonic and low-temperature evolution of the northern Brasília Fold Belt, Brazil

The 40Ar/39Ar ages (muscovite and biotite) and P-T estimations presented here allow us to reconstruct the Pressure–Temperature–time (P–T–t) path from the metamorphic peak to the generation of the orogenic Au (As, Bi, Ag) mineralization in the Buracão area. The application of software-based pseudosections for bulk phyllite composition allows us to better recognize three main stages in the P-T-t path. Rocks from the study area evolved from (i) syn-D1a greenschist metamorphic peak (T = 480–550 °C and P < 4.0 kbar) attained at ca. 538–530 Ma during the W-E shortening related to local D1 deformational stage, which is regionally reported in the external domain of the northern Brasilia Fold Belt. These younger ages, compared to those of mafic and felsic granulites from the northernmost internal domain west of the study area (ca. 610–570 Ma), indicate that the metamorphic peak in the external domain was attained after the internal domain. The (ii) syn-D1b barren type I quartz vein formation (T = 510–260 °C and P < 4.0 kbar) at ca. 531–525 Ma; and (iii) syn-D2a ore-bearing type II quartz vein formation and gold mineralization (T = 345–285 °C and P = 2.7–1.6 kbar) at ca. 522–515 Ma suggest that low temperature may represent cooling P-T conditions of the peripheral supracrustal cover. Moreover, the diachronicity between the local metamorphic peak and the gold mineralization (22 M.y.) is consistent with the structural relationship between gold veins and post-metamorphic peak D2a high deformation zones, which may have acted as fluid corridors through the metasedimentary pile. These features are coherent with the time span observed in several orogenic gold deposits worldwide, especially those associated with high-angle transpressive shear zones developed in the late stages of orogeny. The combination of the Ar–Ar petrochronology with previous published fluid reconstruction and tectonic data suggests metal-rich fluid percolated along regional shear zones through the Traíras Formation under post-metamorphic peak conditions. This regional tectonic and chronology might be useful for geodynamical reconstruction and as a prospection guide in poorly studied orogenic gold of the area.

Analysis and interpretation of geophysical data to delineate the geologic structures of Abu Dabbab area, South Eastern Desert, Egypt

ABSTRACT The present study aims to identify the geologic structure of the Abu Dabbab area. The previous work state that the study area contains different ore minerals such as Tantalum, Niobium, Cassiterite, Gold, and sulphides. Processing, analysis, and interpretation of aeromagnetic and recorded seismic events data of the study area were to define the seismic activity zones and the main trend in the study area and its relation with ore deposits distribution. The area is controlled by different structural elements of trends NE-SW, NNW-SSE, and E-W. The results indicated that most of ore deposits are located at an active fault zone which is characterised by high seismic activity. There are high deformation zone trends NE-SW. There is a high value zone located approximately at the centre of the northern portion of the study area. This high energy zone is oriented towards NE and extends to the Red Sea. The energy map shows that the energy released from the study area is considered as a part of the energy release of the Red Sea area suggesting a tectonic connection between this region and the Red Sea.

Satellite InSAR as a New Tool for the Verification of Landslide Engineering Remedial Works at the Regional Scale: A Case Study in the Three Gorges Resevoir Area, China

Several countries worldwide are funding large-scale programs to mitigate landslide risk by implementing engineering remedial works. However, the overall effectiveness of such measures is rarely monitored, and they are typically performed at the slope scale without fully exploiting the wide-area capabilities of remote sensing technologies. A multi-scale and multi-source monitoring procedure for evaluating the slope stability and the effectiveness of related remedial works was proposed in this study and applied in the middle section of the Three Gorges Reservoir Area (TGRA), China. The area is highly exposed to landslide hazards, and a massive program of engineering remedial works was recently implemented. Satellite interferometric synthetic aperture radar (InSAR)-based techniques were first exploited at the regional scale with the objective to provide a general overview of the deformative scenario and to highlight localized problems (active landslides or high deformation zones) to be further investigated; then, local-scale field investigation and multi-source ground monitoring data were employed to verify the deforming states of active landslides and to evaluate the effectiveness of the landslide engineering remedial works. The results indicated that, among the 310 mapped landslides in the study area, 52 were identified to be active and in a slow-moving state by satellite InSAR; Among the 58 controlled landslides, 9 of them were suspected to be active in a slow-moving state and require further concern. Particular attention was paid to two controlled landslides that were found in a continuously and progressively deforming state. We observed that the regional-scale program of slope stabilization was highly successful; however, the variation of the surrounding environmental setting could have led to landslide reactivation or partial invalidation of the landslide remedial works. The proposed multi-scale and multi-source monitoring framework is low-cost, easy to perform, and very straightforward to communicate to citizens and authorities. It can be easily implemented with very wide areas to assess the slope stability and to investigate the effectiveness of large-scale governmental risk mitigation programs, identifying precursor signals that could allow for intervention before reaching critical conditions.

Method of load calculation of electrical drives of rolling mills during heavy plate manufacturing

During manufacturing of heavy strips and plates from difficult-to-form steel grades on sheet and wide-strip rolling mills there is a problem of exact calculation of power parameters of rolling. It is pointed out that known methods do not provide required precise information at high deformation zones in a stand. An improved calculation method for rolling pressure and load torque of electrical drive engine is suggested further. This method considers peculiar strain of product in high deformation zones and its accelerated motion in reverse mode. Improved analytical dependences for rolling pressure and load torque of electrical drive are reviewed. Control flow chart and main screen of developed software for calculation of wide- strip rolling parameters are presented. Comparative analysis of calculation data and experimental results of engine equivalent currents during tube steels rolling is made. As a result improved precision of calculation method is justified.

ОЦЕНКА ВОЗМОЖНОСТИ ПРИМЕНЕНИЯ ПОДСТУЖИВАНИЯ ЗАГОТОВКИ ДЛЯ БОРЬБЫ С НЕОДНОРОДНОСТЬЮ ДЕФОРМАЦИЙ ПО ВЫСОТЕ ЗАГОТОВКИ

In the article considers the problem of the heterogeneity of grain caused by the dissipation of stresses and non-uniform examination of the high deformation zone. To reduce the inhomogeneous deformation in the work it is proposed to use forced calling-dawn to create more hot and pliable to deform the middle billet. The paper also notes that calling-dawn can be reason of freezing the sidewall billet. To estimate the temperature field in the workpiece, a mathematical model of cooling on the workpiece is developed. The mathematical model is based on the solution of the heat equation by finite difference method. At the decision the four-point implicit scheme of Samarskii is used. The problem is solved in the cylindrical coordinate system, and takes into account the cooling in the radial direction and length. As boundary conditions, the symmetry conditions, the temperature derivative equality at the coordinate zero, and on the surface the mixed boundary condition considering radiation according to the Stefan-Boltzmann law and convective heat exchange according to the Newton-Richmann law are used. It is proposed to use shielding of radiated energy to reduce end face hardening. A formula is given to estimate the conditional emissivity factor, taking into account the reflected energy screen. In the article calculations of the temperature field according to the method given in the work are carried out. Also the estimation of the difference of the resistance to plastic deformation according to the law of the Zener-Holomon subject to a constant strain and rate of deformation. The conclusion about the futility of the use of calling-dawn of the workpiece in the described way in order to deal with heterogeneity of deformation. After the calculation it was found that short-term calling-dawn of the workpiece with the use of screens can lead to the small alignment of the temperature field along the length of the workpiece.

Grain damage, phase mixing and plate-boundary formation

The generation of plate tectonics on Earth relies on complex mechanisms for shear localization, as well as for the retention and reactivation of weak zones in the cold ductile lithosphere. Pervasive mylonitization, wherein zones of high deformation coincide with extensive mineral grain size reduction, is an important clue to this process. In that regard, the grain-damage model of lithospheric weakening provides a physical framework for both mylonitization and plate generation, and accounts for the competition between grain size reduction by deformation and damage, and healing by grain growth. Zener pinning at the evolving interface between mineral components, such as olivine and pyroxene, plays a key role in helping drive grains to small mylonitic sizes during deformation, and then retards their growth once deformation ceases. The combined effects of damage and pinning, however, rely on the efficiency of inter-grain mixing between phases (e.g., olivine and pyroxene) and grain dispersal, which likely depends on grain size itself. Here we present a new model for inter-grain mixing and damage and the onset of rapid mixing. The model considers the competition between the formation of new grains behind a receding interphase triple junction (e.g., olivine growing into a boundary between two pyroxene grains) and their severance or spalling during progressive deformation and damage. The newly formed grains of one phase are then transported along the opposing phase's grain-boundaries and the two phases become dispersed at the grain-scale in a growing mixed layer. The small intermixed grains also affect the grain evolution of the surrounding host grains by Zener pinning, and hence influence the rheology and growth of the mixed layer. As the grains in the mixed layer shrink, subsequently spalled new grains are also smaller, causing a feedback that leads to more rapid mixing and shear localization in the mixed layer. The early stages of mixing can be compared to laboratory experiments, but the transition to a steady-state localized mixed layer, as a proxy for a mylonitic zone, can take a few million years at mid lithospheric conditions. Moreover, a transition in mixing efficiency occurs as grain size reduces, which can induce hysteretic behavior, wherein strong, slowly deforming regions can co-exist with weak rapidly deforming zones, analogous to plate tectonic states with large strong plates and narrow weak boundaries.

Numerical modeling of mullions in the Taili high deformation zone, North China: Implications for the rheology of granitic rocks

This paper presents a combined field measurement and finite element modeling analysis of the mullions occurring on the contact of two granitic rocks with different grain size in the Taili High-Strain Deformation Zone (THDZ), West Liaoning of North China. All of the field data are located in the plot zone of the modeling results. Numerical modeling results indicate that: (1) The inter-angle between the tangent lines cross the cusp point and the ratio R of amplitude and width of mullions are the most effective parameters to describe the geometric shape and evolution of mullions, as well as useful indicators of the rheology of rocks. (2) The competence contrast controls the growth rate of mullions under shortening. It determines the possible ratio R of final mullions. Moreover, decreasing of the cusp angle in high competence contrast materials is faster than that in low competence contrast model. (3) The initial disturbance is an essential factor for the generation of mullions. Those contacts with higher initial disturbance will develop into mullions more easily and have a high growth rate during the same shortening deformation regime. (4) The rheology and deformation behavior of the granitic rocks in the study area are primarily controlled by the grain sizes of quartz and feldspar. The effective viscosity ratio of biotite adamellite and granitic gneisses is about 0.01–0.5. The deformation mechanisms of these granitic rocks should be dominated by a grain-size-sensitive diffusion creep.

Improving Reliability of Hot Plate Mill Electromechanical System

The paper considers issues of a mathematical model development of a “deformation zone - main electric drive” concerning hot plate mills. The dependence of the calculation of rolling torque on features of high deformation zone is given. Based on the obtained expressions, the structural diagram of the deformation zone model has been developed. The paper specifies the structure of the mathematical model for electric drive speed control system based on the known equations of synchronous motor. After the comparison of the transient processes of the electric drive coordinates and rolling settings obtained at the modeling and oscillography at the mill the conformity of the developed model to the studied object has been proved. The provided mathematical model is recommended to analyze the dynamic percussion leads that occurred at hot plate mill. The model obtained allows it to improve the reliability of the electromechanical system owing to the adaptation of the rolling schedule at the real-time operation mode.

GIS multi-criteria decision analysis for assessment and mapping of neotectonic landscape deformation: A case study from Crete

This study of drainage systems in a tectonically active region is based on the Geographical Information Systems (GIS) integration of data from an analytic hierarchy process (AHP) and a weighted linear combination (WLC) procedure with multiple criteria data. A set of thematic maps were produced, based on existing geological maps and freely-available ASTER Global DEM elevation data, using various geological information (i.e. lineaments and lithologies), geomorphometric indices (i.e. slope gradient, drainage density, stream frequency, and the topographic wetness index) and morphotectonic indices (i.e. amplitude of relief and stream length gradient) that highlight areas of neotectonic landscape deformation. The weights of the factors were determined using AHP and WLC. A neotectonic landscape deformation index (NLDI) is computed as the sum of the various weighted factors to provide a map of NLDI distribution across the study region (western Crete). The main objective of this study was to analyse and map the intra-basin spatial variations in neotectonic landscape deformation: five classes, very low to very high, were determined. High to very high deformation zones are linked with known and newly detected active fault zones. The methodology could be developed into a low-cost technique for assessing seismic hazard, guiding disaster risk reduction activities. It can provide an alternative to the Interferometric Synthetic Aperture Radar (InSAR) approach for highlighting zones of neotectonic deformation, particularly in regions where dense vegetation or snow cover renders InSAR ineffective.

Receiver function images of the Hellenic subduction zone and comparison to microseismicity

Abstract. New combined P receiver functions and seismicity data obtained from the EGELADOS network employing 65 seismological stations within the Aegean constrained new information on the geometry of the Hellenic subduction zone. The dense network and large data set enabled us to estimate the Moho depth of the continental Aegean plate across the whole area. Presence of a negative contrast at the Moho boundary indicating the serpentinized mantle wedge above the subducting African plate was seen along the entire forearc. Furthermore, low seismicity was observed within the serpentinized mantle wedge. We found a relatively thick continental crust (30–43 km) with a maximum thickness of about 48 km beneath the Peloponnese Peninsula, whereas a thinner crust of about 27–30 km was observed beneath western Turkey. The crust of the overriding plate is thinning beneath the southern and central Aegean and reaches 23–27 km. Unusual low Vp / Vs ratios were estimated beneath the central Aegean, which most likely represent indications on the pronounced felsic character of the extended continental Aegean crust. Moreover, P receiver functions imaged the subducted African Moho as a strong converted phase down to a depth of about 100 km. However, the converted Moho phase appears to be weak for the deeper parts of the African plate suggesting nearly complete phase transitions of crustal material into denser phases. We show the subducting African crust along eight profiles covering the whole southern and central Aegean. Seismicity of the western Hellenic subduction zone was taken from the relocated EHB-ISC catalogue, whereas for the eastern Hellenic subduction zone, we used the catalogues of manually picked hypocentre locations of temporary networks within the Aegean. Accurate hypocentre locations reveal a significant change in the dip angle of the Wadati–Benioff zone (WBZ) from west (~ 25°) to the eastern part (~ 35°) of the Hellenic subduction zone. Furthermore, a zone of high deformation can be characterized by a vertical offset of about 40 km of the WBZ beneath the eastern Cretan Sea. This deformation zone may separate a shallower N-ward dipping slab in the west from a steeper NW-ward dipping slab in the east. In contrast to hypocentre locations, we found very weak evidence for the presence of the slab at larger depths in the P receiver functions, which may result from the strong appearance of the Moho multiples as well as eclogitization of the oceanic crust. The presence of the top of a strong low-velocity zone at about 60 km depth in the central Aegean may be related to the asthenosphere below the Aegean continental lithosphere and above the subducting slab. Thus, the Aegean mantle lithosphere seems to be 30–40 km thick, which means that its thickness increased again since the removal of the mantle lithosphere about 15 to 35 Ma ago.

The Determination of Energy-power Parameters of Hot Plate Mill Mechatronic System

The paper considers issues of energy-power parameters determination of mechatronic system of hot plate mill. The dependence of the calculation of roll torque on features of high deformation zone is given. Based on the obtained expressions the structural diagram of the deformation zone model has been developed. The adequacy of specified method for calculation of energy-power parameters was checked and proved. Results of the experimental studies proved the correctness of conclusions to use specified method during rough rolling as well as finish rolling on the hot plate mill.

Numerical modeling on progressive internal deformation in down-built diapirs

A two-dimensional finite difference code (FDCON) is used to estimate the finite deformation within a down-built diapir. The geometry of the down-built diapir is fixed by using two rigid rectangular overburden units which sink into a source layer of a constant viscosity. Thus, the model refers to diapirs consisting of a source layer feeding a vertical stem, and not to other salt structures (e.g. salt sheets or pillows). With this setup we study the progressive strain in three different deformation regimes within the “salt” material: (I) a squeezed channel-flow deformation regime and (II) a corner-flow deformation regime within the source layer, and (III) a pure channel-flow deformation regime within the stem. We analyze the evolution of finite deformation in each regime individually, progressive strain for particles passing all three regimes, and total 2D finite deformation within the salt layer. Model results show that the material which enters the stem bears inherited strain accumulated from the other two domains. Therefore, finite deformation in the stem differs from the expected channel-flow deformation, due to the deformation accumulated within the source layer. The stem displays a high deformation zone within its center and areas of decreasing progressive strain between its center and its boundaries. High deformation zones within the stem could also be observed within natural diapirs (e.g. Klodowa, Polen). The location and structure of the high deformation zone (e.g. symmetric or asymmetric) could reveal information about different rates of salt supplies from the source layer. Thus, deformation pattern could directly be correlated to the evolution of the diapir.

Transfer of deformation in back-arc basins with a laterally variable rheology: Constraints from analogue modelling of the Balkanides–Western Black Sea inversion

The balance between extension and contraction in back-arc basins is very sensitive to a number of parameters related to on-going subduction and collision processes. This leads to complex back-arc geometries, where a lateral transition between crustal blocks with contrasting rheologies is often recorded. One good example is the back-arc region of the Balkanides–Pontides orogens, where lateral variations in rheologies are observed between the Balkanides–Moesian block and the Pontides–Western Black Sea Basin. The latter opened during Cretaceous–Eocene, and has been inverted together with the former starting during late Middle Eocene. The inversion generated contrasting geometries along the orogenic strike, with a narrow zone of high deformation in the Balkanides–Moesia region, wide areas of thrusting with low offsets in the Pontides–Western Black Sea Basin and a transitional zone characterized by highly curved geometries. This overall type of inversion is investigated here by the means of analogue modelling testing the role of inherited crustal geometries during inversion. Our modelling suggests that the contrasting architecture of inverted structures observed in the Balkanides–Pontides domain are the result of pre-existing crustal stretching geometries of various blocks inherited from the Cretaceous–Eocene extension. The stretched and weak back-arc basins can transfer contraction deformation at large distances, explaining structures derived by observational studies. The collisional deformation recorded in the Pontides was transmitted at large distances that are in the range of the contraction structures observed in the centre and northern part of the Western Black Sea. In the light of analogue modelling results we argue that the Western Black Sea was a rheologically weaker domain when compared with the adjacent western onshore at the beginning of the inversion, in contrast with previous results derived from numerical modelling studies that argued for a strong West Black Sea domain at the beginning of inversion.

Mechanical and damage analysis along a flat-rolled wire cold forming schedule

Numerical simulation is used to study patented high-C steel flat-rolled wire cold forming processes. An elasto-plastic power law, identified from mechanical tests, is used into Forge2005® finite element (FEM) package in order to describe the material behaviour during wire drawing followed by cold rolling. A through-process approach has been favoured, transferring residual wire-drawing stresses and strain into the flat-rolling preform. This mechanical analysis, associated with a triaxiality study, points to dangerous areas where fracture may initiate due to high tensile stresses. Lemaitre’s isotropic damage criterion, including crack closure effect, a -1/3 cut-off value of stress triaxiality, and tension/compression damage asymmetry, has been used and has confirmed the previous analysis. A number of non-coalesced voids nucleated on inclusions have been observed in the Scanning Electron Microscopy (SEM), especially in high-deformation zones (“blacksmith’s cross”). Their evolution has been simulated in the FEM model using spherical numerical markers, which deform into oblate or prolate ellipsoids. The deformation-induced morphological evolution of voids observed in the SEM compares well with the geometrical evolution of the markers, which suggests that the morphologies observed do not result from micro-crack propagation, but from material transport of the nucleated voids.

Structure of Sumatra and its implications for the tectonic assembly of Southeast Asia and the destruction of Paleotethys

AbstractIt is now generally accepted that Southeast Asia is composed of continental blocks which separated from Gondwana with the formation of oceanic crust during the Paleozoic, and were accreted to Asia in the Late Paleozoic or Early Mesozoic, with the subduction of the intervening oceanic crust. From east to west the Malay peninsula and Sumatra are composed of three continental blocks: East Malaya with a Cathaysian Permian flora and fauna; Sibumasu, including the western part of the Malay peninsula and East Sumatra, with Late Carboniferous–Early Permian ‘pebbly mudstones’ interpreted as glaciogenic diamictites; and West Sumatra, again with Cathaysian fauna and flora. A further unit, the Woyla nappe, is interpreted as an intraoceanic arc thrust over the West Sumatra block in the mid Cretaceous. There are varied opinions concerning the age of collision of Sibumasu with East Malaya and the destruction of Paleotethys. In Thailand, radiolarites have been used as evidence that Paleotethys survived until after the Middle Triassic. In the Malay peninsula, structural evidence and the ages of granitic intrusions are used to support a Middle Permian to Early Triassic age for the destruction of Paleotethys. It is suggested that the West Sumatra block was derived from Cathaysia and emplaced against the western margin of Sibumasu by dextral transcurrent faulting along a zone of high deformation, the Medial Sumatra Tectonic Zone. These structural units can be traced northwards in Southeast Asia. The East Malaya block is considered to be part of the Indochina block, Sibumasu can be traced through Thailand into southern China, the Medial Sumatra Tectonic Zone is correlated with the Mogok Belt of Myanmar, the West Burma block is the extension of the West Sumatra block, from which it was separated by the formation of the Andaman Sea in the Miocene, and the Woyla nappe is correlated with the Mawgyi nappe of Myanmar.

Coupling Finite Element and Mesh-free Methods for Modelling Brain Deformation in Response to Tumour Growth

Very little is known about the deformation effects of tumour growth within the brain. Computer simulations have the potential to calculate such deformations. A method for computing localised high deformations within the brain’s soft tissue is presented. Such knowledge would be significant towards neuroscience and neurosurgery, particularly for quantifying tumour aggressiveness, therapy planning, as well as surgical planning and simulation. A Finite Element mesh used in the vicinity of a growing tumour is very quickly destroyed and cannot be used reliably unless complicated automatic re-meshing exists. Mesh-free methods are capable of handling much larger deformations, however are known to be less reliable that Finite Element analysis for moderate deformations. A mixed-mesh approach utilises mesh-free regions within localised high-deformation zones, with the remaining model comprised of a Finite Element mesh. In this study, a new algorithm is proposed coupling the Finite Element and Element Free Galerkin methods for use in applications of high localised deformation, such as brain tumour growth. The algorithm is verified against a number of separate Finite Element and mesh-free problems solved via validated/commercial software. Maximum errors of less than 0.85 mm were maintained, corresponding to the working resolution of an MRI scan. A mixed-mesh brain model is analysed with respect to different tumour growth volumes located behind the left ventricle. Significant displacements of up to 9.66 mm surrounding a 4118 mm3 sized tumour are noted, with 14.5% of the brain mesh suffering deformation greater than 5 mm.

Application of the EBSD technique for the characterisation of deformation zones in metal cutting

The Electron Back Scattering Diffraction (EBSD) technique was applied for mapping the extent of plastic deformation zones of single and two-phase steels subjected to orthogonal cutting using the quick-stop method. The analysis of the EBSD patterns obtained indicates that the method appears to be applicable for investigating deformation in a chip root and is well suited for the analysis of the deformation zones ahead of the tool tip in the vicinity of the primary deformation zone Z 1. Though the EBSD patterns (EBSPs) could not be resolved clearly in the chip in the case of materials displaying continuous chips (Remko iron, carbon steels), the analysis was more successful for materials exhibiting shear-localised chips such as austenitic steel, due to the presence of alternating low and high deformation zones. The presence of slip lines within the deformed grains in the austenitic chip material was clearly noticeable and also evidence of twinning deformation was found. The EBSD analysis of the machined surfaces indicated that the deepest heavily deformed area was found for the Remko iron material and the smallest for the austenitic variant. These results were also confirmed by microhardness profiling in the machined surfaces.

Application of data integration for deformation potential mapping using remotely acquired data sets within the Lynn Lake Greenstone Belt, northwestern Manitoba, Canada

The purpose of this paper is to demonstrate the ability of combining remotely acquired data using data integration techniques to define lineament trends that may represent high-strain zones within the Lynn Lake Greenstone Belt. A knowledge-driven data integration approach has been adopted for this study that makes use of theoretical principles and good working knowledge of the regional geology to translate components of a shear-hosted gold conceptual model into a spatial model. Lineaments extracted from airborne vertical gradient magnetic data (VG), very low frequency electromagnetic data (VLF-EM), and RADARSAT synthetic aperture radar (SAR) data are used as evidence for the occurrence of shear zones. Proximity maps created from the extracted lineaments are weighted based on deformational characteristics of shear zones. Combination of these proximity maps, using fuzzy logic and Dempster-Shafer theory, produces a potential for deformation map. Field mapping was undertaken to verify the accuracy of the deformation potential maps generated. Detailed strike-perpendicular structural mapping in areas of above-average outcrop exposure identified a series of subparallel D2 shear zones, which correlated with areas of high deformation potential. Other potential areas of high deformation were field checked and found to represent D2 shear zones not identified during structural mapping. Deformation potential mapping proved invaluable in the interpretation of the western strike extension of the Johnson Shear Zone (JSZ) and demonstrates the broadening of the JSZ west of the Gemmel Lake area. The results from this paper have major implications for future gold exploration in the belt and have demonstrated that VG, VLF, and SAR data can be useful tools to assist in the delineation of major structural trends and high deformation zones within greenstone belts.