Controls on the evolution of strength and failure style in shallow rock slope failures

Rock fall failure comprises fracturing through zones of intact rock, known as rock bridges, and kinematic release along discontinuity surfaces. Understanding controls on magnitude – frequency relationships of rockfalls, and their associated failure characteristics aids susceptibility analysis and interpretation of pre-failure deformation. For failure to occur, these rock bridges must have been weakened, with this damage accumulation driven by a suite of weathering processes. This thesis aims to explore the spatial and temporal controls on weathering induced strength degradation and its subsequent influence on the mechanics of rockfall detachment. Within this, it examines the role of gravitational ambient stress, as dictated by slope topography and rock mass structure, which recent research suggests influences the efficiency of weathering processes. The project integrates field observations, analogue experiments and numerical modelling over varying spatial scales. Terrestrial laser scanning and gigapixel photography are combined to forensically map rock bridge attributes within rockfall detachment surfaces. The role of slope geometry and rock mass structure in concentrating stress is assessed via conceptual finite element models. Finally, samples are subjected to stress conditions induced by the slope structure and environmental conditions in a series of weathering analogue experiments. Together, these results indicate that weathering significantly reduces intact rock strength with areas of stress concentration purely a mechanical control on rockfall release rather than a temporal control on weakening. Weaker rock is characterised by substantial post-peak strength, which requires multiple stages of brittle fracture before ultimate failure occurs. This in turn influences the stages of failure required through rock bridges before final failure, with this number of rock bridges dependent on rockfall size. Mechanically, failure mode is dependent on rock bridge proportion, distribution and location for individual rockfalls. A conceptual model describes magnitude-frequency characteristics and the observable pattern of pre-failure deformation expected for different stages of weathering

Aggregation characteristics and maturity of Peak District soils

Soil aggregation and aggregate stability are fundamental factors in determination of soil erodibility. The aggregation characteristics of soils in a region of high erosion potential are measured, and controlling factors examined. A relationship between increasing soil maturity and decreasing aggregate stability is described, and its significance in relation to Penck’s Aufbereitung concept is discussed

Local feature extraction based facial emotion recognition: a survey

Notwithstanding the recent technological advancement, the identification of facial and emotional expressions is still one of the greatest challenges scientists have ever faced. Generally, the human face is identified as a composition made up of textures arranged in micro-patterns. Currently, there has been a tremendous increase in the use of local binary pattern based texture algorithms which have invariably been identified to being essential in the completion of a variety of tasks and in the extraction of essential attributes from an image. Over the years, lots of LBP variants have been literally reviewed. However, what is left is a thorough and comprehensive analysis of their independent performance. This research work aims at filling this gap by performing a large-scale performance evaluation of 46 recent state-of-the-art LBP variants for facial expression recognition. Extensive experimental results on the well-known challenging and benchmark KDEF, JAFFE, CK and MUG databases taken under different facial expression conditions, indicate that a number of evaluated state-of-the-art LBP-like methods achieve promising results, which are better or competitive than several recent state-of-the-art facial recognition systems. Recognition rates of 100%, 98.57%, 95.92% and 100% have been reached for CK, JAFFE, KDEF and MUG databases, respectively

Preservation of biogenerated mixed facies: A case study from the Neoproterozoic Villa Mónica formation, Sierra La Juanita, Tandilia, Argentina

The aim of this contribution was to show through field work and mineralogical microtextural studies a complex history of weathering and diagenesis in the Villa Mónica Formation, the most ancient Neoproterozoic unit of the Tandilia System and to present a proposal of a paragenetic sequence. This unit also shows microbially induced structures described here for the first time. At the Estancia La Siempre Verde, La Placeres and Don Camilo quarries, Sierra La Juanita, near Barker locality, the Villa Mónica Formation is composed of carbonate facies, classically defined for more than 40 years as siliciclastic facies and of reinterpreted mixed facies: carbonate/siliciclastic and heterolithic respectively, both bearing biosignatures. The carbonates are represented by well-preserved columnar head stromatolite boundstones and by laminar microbial mat deposits. Both of them were the host rocks - identified here for the first time - of individual or random aggregates of pyramidal quartz megacrystals and they were later dolomitized, silicified, illitized and hematized. The siliciclastics are composed of quartz grains trapped within both the stromatolites and the microbial mats, of illitic siltstones and claystones and of quartzitic sandstones. Illuviation processes transported cutans to lower horizons. Syndiagenesis involved dolomitization and silicification while burial diagenesis produced pressure-solution effects by overburden and neoformation of minerals: diagenetic illite with rutile needles, among others. Compressive movements from the SW, responsible for basin inversion: telodiagenesis (uplift, fracturing, folding and introduction of meteoric fluids), affected the Villa Mónica Formation with neoformation/transformation of minerals: kaolinite, halloysite and smectite, development of slickensides (stress cutans) and ferriargillans, hydration, dedolomitization and calcification.Facultad de Ciencias Naturales y MuseoCentro de Tecnología de Recursos Minerales y Cerámic

Preservation of biogenerated mixed facies: A case study from the Neoproterozoic Villa Mónica formation, Sierra La Juanita, Tandilia, Argentina

The aim of this contribution was to show through field work and mineralogical microtextural studies a complex history of weathering and diagenesis in the Villa Mónica Formation, the most ancient Neoproterozoic unit of the Tandilia System and to present a proposal of a paragenetic sequence. This unit also shows microbially induced structures described here for the first time. At the Estancia La Siempre Verde, La Placeres and Don Camilo quarries, Sierra La Juanita, near Barker locality, the Villa Mónica Formation is composed of carbonate facies, classically defined for more than 40 years as siliciclastic facies and of reinterpreted mixed facies: carbonate/siliciclastic and heterolithic respectively, both bearing biosignatures. The carbonates are represented by well-preserved columnar head stromatolite boundstones and by laminar microbial mat deposits. Both of them were the host rocks - identified here for the first time - of individual or random aggregates of pyramidal quartz megacrystals and they were later dolomitized, silicified, illitized and hematized. The siliciclastics are composed of quartz grains trapped within both the stromatolites and the microbial mats, of illitic siltstones and claystones and of quartzitic sandstones. Illuviation processes transported cutans to lower horizons. Syndiagenesis involved dolomitization and silicification while burial diagenesis produced pressure-solution effects by overburden and neoformation of minerals: diagenetic illite with rutile needles, among others. Compressive movements from the SW, responsible for basin inversion: telodiagenesis (uplift, fracturing, folding and introduction of meteoric fluids), affected the Villa Mónica Formation with neoformation/transformation of minerals: kaolinite, halloysite and smectite, development of slickensides (stress cutans) and ferriargillans, hydration, dedolomitization and calcification.Facultad de Ciencias Naturales y MuseoCentro de Tecnología de Recursos Minerales y Cerámic

Hydrologic response to spring snowmelt and extreme rainfall events of different landscape elements within a prairie wetland basin

Depressions in the prairie pothole region (PPR) are commonly referred to as sloughs and were formed during the most recent glacial retreat, ~10-17 kyrs ago. They are hydrologically isolated, as they are not permanently connected by surface inflow or outflow channels. Extreme thunderstorms are common across the prairies and the hydrologic response of isolated wetlands to intense rainfall events is poorly understood. The purpose of this study was to compare the response of different landscape/ecological elements of a prairie wetland to snowmelt and extreme rainstorms. Comparisons were completed by investigating the spring snowmelts of 2005 and 2006 and the rainstorm event of June 17 - 18, 2005, in which 103 mm fell at the St. Denis National Wildlife Area (NWA) Saskatchewan, Canada (106°06'W, 52°02'N). The wetland was separated into five landscape positions, the pond center (PC), grassed edge (GE), tree ring (TR), convex upland (CXU), and concave upland (CVU). Comparison of the rainfall of June 17 – 18, 2005 with the spring snowmelts of 2005 and 2006 indicates that the hydrologic consequences of these different events are similar. Overland flow, substantial ponding in lowlands, and recharge of the groundwater occur in both cases. Analysis of this intense rainfall has provided evidence that common, intense rainstorms are hydrologically equivalent to the annual spring snowmelt, the major source of water for closed catchments in the PPR

FER Based on Fusion Features of CS-LSMP

Local feature descriptors play a fundamental and important role in facial expression recognition. This paper presents a new descriptor, Center-Symmetric Local Signal Magnitude Pattern (CS-LSMP), which is used for extracting texture features from facial images. CS-LSMP operator takes signal and magnitude information of local regions into account compared to conventional LBP-based operators. Additionally, due to the limitation of single feature extraction method and in order to make full advantages of different features, this paper employs CS-LSMP operator to extract features from Orientational Magnitude Feature Maps (OMFMs), Positive-and-Negative Magnitude Feature Maps (PNMFMs), Gabor Feature Maps (GFMs) and facial patches (eyebrows-eyes, mouths) for obtaining fused features. Unlike HOG, which only retains horizontal and vertical magnitudes, our work generates Orientational Magnitude Feature Maps (OMFMs) by expanding multi-orientations. This paper build two distinct feature maps by dividing local magnitudes into two groups, i.e., positive and negative magnitude feature maps. The generated Gabor Feature Maps (GFMs) are also grouped to reduce the computational complexity. Experiments on the JAFFE and CK+ facial expression datasets showed that the proposed framework achieved significant improvement and outperformed some state-of-the-art methods