Application of discrete fracture networks (DFN) in the stability analysis of Delabole Slate Quarry, Cornwall, UK

This is the author accepted manuscript. The final version is available from ARMA.50th US Rock Mechanics/Geomechanics Symposium, Houston, USA, 26-29 June 2016The failure mechanism of rock slopes is mainly controlled by the strength and orientation of discontinuities within the rock mass. A realistic representation of the joint network within the rock mass is therefore an essential component of stability analysis of rock structures (e.g. rock slopes, tunnels etc.). Discontinuity persistence and connectivity are significant parameters which control the stability of rock slopes. A small percentage of rock bridges on the discontinuity surface can significantly increase its strength and prevent slope failure. Discontinuities within the rock mass are rarely fully connected. In practice, however, discontinuities are often assumed fully persistent due to the difficulties both in mapping and simulation of non-persistence. Discrete fracture networks (DFN) provide a rigorous and convenient tool for the simulation of joint systems within a rock mass. Utilizing statistical methods, DFNs consider the stochastic nature of some key parameters (e.g. persistence and orientation) within numerical models. Discrete fracture network engineering is increasingly used due to recent developments in discontinuity data acquisition techniques (e.g. ground-based digital photogrammetry and laser scanning). Recent development in geomechanical modelling codes and increased computing power have also allowed to either import DFN’s into models or to generate DFN’s within the numerical modelling code itself (e.g. 3DEC). This paper describes the use of photogrammetry at the Delabole slate quarry in Cornwall, UK for remotely acquiring key discontinuity parameter data (orientation, intensity and length) and its subsequent use in developing statistically validated discrete fracture network parameters. The 3D distinct element code, 3DEC, is used for the DFN generation and subsequent stability analysis. Several realizations of the 3DEC-DFN models are run to investigate the stochastic nature of discontinuities within the quarry and their potential influence on the stability of the pit. Finally the simulation results are used to determine the slope instability mechanisms and determine the most likely areas of potential instability

Application of RQD-Number and RQD-Volume multifractal modelling to delineate rock mass characterisation in Kahang Cu-Mo porphyry deposit, central Iran.

Identification of rock mass properties in terms of Rock Quality Designation (RQD) plays a significant role in mine planning and design. This study aims to separate the rock mass characterisation based on RQD data analysed from 48 boreholes in Kahang Cu-Mo porphyry deposit situated in the central Iran utilising RQD-Volume (RQD-V) and RQD-Number (RQD-N) fractal models. The log-log plots for RQD-V and RQD-N models show four rock mass populations defined by RQD thresholds of 3.55, 25.12 and 89.12% and 10.47, 41.68 and 83.17% respectively which represent very poor, poor, good and excellent rocks based on Deere and Miller rock classification. The RQD-V and RQD-N models indicate that the excellent rocks are situated in the NW and central parts of this deposit however, the good rocks are located in the most parts of the deposit. The results of validation of the fractal models with the RQD block model show that the RQD-N fractal model of excellent rock quality is better than the RQD-V fractal model of the same rock quality. Correlation between results of the fractal and the geological models illustrates that the excellent rocks are associated with porphyric quartz diorite (PQD) units. The results reveal that there is a multifractal nature in rock characterisation with respect to RQD for the Kahang deposit. The proposed fractal model can be intended for the better understanding of the rock quality for purpose of determination of the final pit slope.The authors are grateful to the National Iranian Copper Industries Co. (NICICO) for their permission to have access to the Kahang deposit dataset. Additionally, the authors would like to thank Mr. Reza Esfahanipour the head of Exploration and Development Department of the NICICO for his support. The authors also are hugely thankful to the Institute of Materials, Minerals and Mining (IOM3) for its financial support in order to conduct this research

Synthetic metallomolecules as agents for the control of DNA structure

This tutorial review summarises B-DNA structure and metallomolecule binding modes and illustrates some DNA structures induced by molecules containing metallic cations. The effects of aquated metal ions, cobalt amines, ruthenium octahedral metal complexes, metallohelicates and platinum complexes such as cis-platin are discussed alongside the techniques of NMR, X-ray crystallography, gel electrophoresis, circular dichroism, linear dichroism and molecular dynamics. The review will be of interest to people interested in both DNA structure and roles of metallomolecules in biological systems

Structure of the Janus Protein Human CLIC2

Chloride intracellular channel (CLIC) proteins possess the remarkable property of being able to convert from a water-soluble state to a membrane channel state. We determined the three-dimensional structure of human CLIC2 in its water-soluble form by X-ray crystallography at 1.8-Å resolution from two crystal forms. In contrast to the previously characterized CLIC1 protein, which forms a possibly functionally important disulfide-induced dimer under oxidizing conditions, we show that CLIC2 possesses an intramolecular disulfide and that the protein remains monomeric irrespective of redox conditions. Site-directed mutagenesis studies show that removal of the intramolecular disulfide or introduction of cysteine residues in CLIC2, equivalent to those that form the intramolecular disulfide in CLIC1, does not cause dimer formation under oxidizing conditions.We also show that CLIC2 forms pH-dependent chloride channels in vitro with higher channel activity at low pH levels and that the channels are subject to redox regulation. In both crystal forms, we observed an extended loop region from the C-terminal domain, called the foot loop, inserting itself into an interdomain crevice of a neighboring molecule. The equivalent region in the structurally related glutathione transferase superfamily corresponds to the active site. This so-called foot-in-mouth interaction suggests that CLIC2 might recognize other proteins such as the ryanodine receptor through a similar interaction

A combined field/remote sensing approach for characterizing landslide risk in coastal areas

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Understanding the key factors controlling slope failure mechanisms in coastal areas is the first and most important step for analyzing, reconstructing and predicting the scale, location and extent of future instability in rocky coastlines. Different failure mechanisms may be possible depending on the influence of the engineering properties of the rock mass (including the fracture network), the persistence and type of discontinuity and the relative aspect or orientation of the coastline. Using a section of the North Coast of Cornwall, UK, as an example we present a multi-disciplinary approach for characterizing landslide risk associated with coastal instabilities in a blocky rock mass. Remotely captured terrestrial and aerial LiDAR and photogrammetric data was interrogated using Geographic Information System (GIS) techniques to provide a framework for subsequent analysis, interpretation and validation. The remote sensing mapping data was used to define the rock mass discontinuity network of the area and to differentiate between major and minor geological structures controlling the evolution of the North Coast of Cornwall. Kinematic instability maps generated from aerial LiDAR data using GIS techniques and results from structural and engineering geological surveys are presented. With this method, it was possible to highlight the types of kinematic failure mechanism that may generate coastal landslides and highlight areas that are more susceptible to instability or increased risk of future instability. Multi-temporal aerial LiDAR data and orthophotos were also studied using GIS techniques to locate recent landslide failures, validate the results obtained from the kinematic instability maps through site observations and provide improved understanding of the factors controlling the coastal geomorphology. The approach adopted is not only useful for academic research, but also for local authorities and consultancy's when assessing the likely risks of coastal instability

The Charging Structure for the Great Barrier Reef - A review of willingness to pay

The Great Barrier Reef Marine Park Authority (GBRMPA or the Reef Authority) is currently conducting a comprehensive review of the charging structure for the use of the Great Barrier Reef (GBR) Marine Park with a view to implement potential changes from 1 July 2023

Measurement of nitrate and nitrite in biopsy-sized muscle samples using HPLC

Studies of rats have indicated that skeletal muscle plays a central role in whole-body nitrate ( NO−3 )/nitrite ( NO−2 )/nitric oxide (NO) metabolism. Extending these results to humans, however, is challenging due to the small size of needle biopsy samples. We therefore developed a method to precisely and accurately quantify NO−3 and NO−2 in biopsy-sized muscle samples. NO−3 and NO−2 were extracted from rat soleus samples using methanol combined with mechanical homogenization + ultrasound, bead beating, pulverization at liquid N2 temperature or pulverization + 0.5% Triton X-100. After centrifugation to remove proteins, NO−3 and NO−2 were measured using HPLC. Mechanical homogenization + ultrasound resulted in the lowest NO−3 content (62 ± 20 pmol/mg), with high variability [coefficient of variation (CV) >50%] across samples from the same muscle. The NO−2 / NO−3 ratio (0.019 ± 0.006) was also elevated, suggestive of NO−3 reduction during tissue processing. Bead beating or pulverization yielded lower NO−2 and slightly higher NO−3 levels, but reproducibility was still poor. Pulverization + 0.5% Triton X-100 provided the highest NO−3 content (124 ± 12 pmol/mg) and lowest NO−2 / NO−3 ratio (0.008 ± 0.001), with the least variability between duplicate samples (CV ~15%). These values are consistent with literature data from larger rat muscle samples analyzed using chemiluminescence. Samples were stable for at least 5 wk at -80°C, provided residual xanthine oxidoreductase activity was blocked using 0.1 mmol/l oxypurinol. We have developed a method capable of measuring NO−3 and NO−2 in <1 mg of muscle. This method should prove highly useful in investigating the role of skeletal muscle in NO−3 / NO−2 /NO metabolism in human health and disease. NEW & NOTEWORTHY Measurement of nitrate and especially nitrite in small, i.e., biopsy-sized, muscle samples is analytically challenging. We have developed a precise, accurate, and convenient method for doing so using an affordable commercial HPLC system

Cardiovascular Functional Changes in Chronic Kidney Disease:Integrative Physiology, Pathophysiology and Applications of Cardiopulmonary Exercise Testing

The development of cardiovascular disease during renal impairment involves striking multi-tiered, multi-dimensional complex alterations encompassing the entire oxygen transport system. Complex interactions between target organ systems involving alterations of the heart, vascular, musculoskeletal and respiratory systems occur in Chronic Kidney Disease (CKD) and collectively contribute to impairment of cardiovascular function. These systemic changes have challenged our diagnostic and therapeutic efforts, particularly given that imaging cardiac structure at rest, rather than ascertainment under the stress of exercise, may not accurately reflect the risk of premature death in CKD. The multi-systemic nature of cardiovascular disease in CKD patients provides strong rationale for an integrated approach to the assessment of cardiovascular alterations in this population. State-of-the-art cardiopulmonary exercise testing (CPET) is a powerful, dynamic technology that enables the global assessment of cardiovascular functional alterations and reflects the integrative exercise response and complex machinery that form the oxygen transport system. CPET provides a wealth of data from a single assessment with mechanistic, physiological and prognostic utility. It is an underutilized technology in the care of patients with kidney disease with the potential to help advance the field of cardio-nephrology. This article reviews the integrative physiology and pathophysiology of cardio-renal impairment, critical new insights derived from CPET technology, and contemporary evidence for potential applications of CPET technology in patients with kidney disease

Application of unmanned aerial vehicle data and discrete fracture network models for improved rockfall simulations

In this research, we present a new approach to define the distribution of block volumes during rockfall simulations. Unmanned aerial vehicles (UAVs) are utilized to generate high-accuracy 3D models of the inaccessible SW flank of the Mount Rava (Italy), to provide improved definition of data gathered from conventional geomechanical surveys and to also denote important changes in the fracture intensity. These changes are likely related to the variation of the bedding thickness and to the presence of fracture corridors in fault damage zones in some areas of the slope. The dataset obtained integrating UAV and conventional surveys is then utilized to create and validate two accurate 3D discrete fracture network models, representative of high and low fracture intensity areas, respectively. From these, the ranges of block volumes characterizing the in situ rock mass are extracted, providing important input for rockfall simulations. Initially, rockfall simulations were performed assuming a uniform block volume variation for each release cell. However, subsequent simulations used a more realistic nonuniform distribution of block volumes, based on the relative block volume frequency extracted from discrete fracture network (DFN) models. The results of the simulations were validated against recent rockfall events and show that it is possible to integrate into rockfall simulations a more realistic relative frequency distribution of block volumes using the results of DFN analyse

Ultrasonic inspection of flooded mineshafts for stability monitoring

This is the author accepted manuscript.The final version is available from Maney via the DOI in this record.Inspecting abandoned mine shafts is critical in ensuring their safety through early identification of signs of deterioration. Since the common inspection methods of CCTV and LiDAR are not very effective underwater, two modules have been designed for inspecting the linings of flooded, abandoned mine shafts. Using sonar technology, they allow the early stages of degradation to the lining to be detected which – since this could be indicative of imminent collapse – provides protection against the consequential risk to property and human life. Detailed measurements of several shafts’ cross-sections have been recorded using profiling and imaging sonar technology. Although imaging sonar provides very different results in the confined and reverberant environment of a mine shaft, compared to its more common environment of a seabed, it was shown that when combined with the profiling sonar, it allows shafts to be surveyed in a shorter period of time and improves the reliability of the profiling function.European Commissio