Effect of strata properties and panel widths on chock performance

AbstractThe selection of optimum chock (support) capacity is very crucial for a successful longwall mining. The selection of chock capacity depends on the site-specific geotechnical parameters, constraints and longwall panel geometry, which are generally not known in detail in priority. Hence, based on the field and laboratory data, various possible combinations should be analyzed to cater for the unforeseeable mining conditions. This paper discusses the use of numerical model for selecting an appropriate chock capacity based on the site-specific geological and geotechnical information and longwall panel geometry. The fracture mechanisms of immediate and main roofs are also discussed for various panel widths and support capacities. For the models considered, the chock convergence is predicted to increase by about 33% due to the increase in face width from 100 to 260m. Similarly, the massive roof strata are found to yield higher chock convergence compared to bedded strata

Automatic/Scalable Firmware and System Software update on Datacenter Products like Server, Storage and Network devices

The invention makes the Datacenter intelligent and scalable in case of “Firmware and System Software updates”. Datacenter ecosystem generally consists of following major components Datacenter Products (Servers, Storage and Network devices) Central Management System (Manages the lifecycle of Datacenter Products). Administrators (Humans maintaining the datacenter) The innovation introduces a new way to do Firmware and System software upgrade and fresh installation on Datacenter Products. This is achieved with two newly introduced software: Smart Update Module The Store Smart Update Module: The Smart Update Module is intelligent software running on a Management Processor. Management processor is small integrated chip inside each Datacenter Product dedicated for managing the lifecycle of each individual Product. Capabilities of the Smart Update Module: Collects the inventory of Firmware and System software of the host Datacenter product. Compares the collected inventory with the Store to check if there are any latest Firmware and System software available for upgrade or fresh installation. Sends alerts to Central Management System (Manager) to notify the Administrator to plan for upgrade. Finally based on Administrator’s planned maintenance window, downloads the Firmware and System Software and upgrades the product. The product can be a Server, Storage and Network devices. The Store: The Store is cloud platform which provides Firmware and System Software over the internet. Capabilities of the Store: The Store contains a huge collection of Firmware and System software required for each Datacenter Product to be usable. The Store always maintains the latest available collection of Firmware and System Software to facilitate upgrades of existing firmware and System software. The Store allows the Smart Update Module to connect and compare its inventory of Firmware and System software against the latest available in the Store. The Store allows the Smart Update Module to pull latest Firmware and System Software for upgrade or fresh installation in case of newly added Datacenter Products. Together with the Smart Update Module and the Store, the entire Firmware and System software upgrade and fresh installation can be made scalable, with increased performance, lightweight Central Management System (Manager) and the entire process is automated

Numerical study of stability and connectivity of vertical goaf drainage holes

During underground longwall coal extraction, overburden strata deformation may result in vertical goaf drainage holes, which are drilled in advance of mining for tail gate gas management, to fail. The performance of these vertical goaf drainage holes is controlled by mine design parameters and local geomechanical properties. This paper investigates the use of advanced 3D finite element modelling and 2D discrete element modelling simulation techniques to understand the fundamentals of vertical goaf drainage hole failure mechanism due to strata shear at a currently operating gassy Australian mine site. Finite element modelling is used to investigate the location of high shear in the overburden strata at the vertical goaf gas drainage hole region during longwall mining and the discrete element modelling is used to examine connectivity from the goaf region to the goaf-gas drainage system.The Anglo-American Metallurgical Coal, Australiahttp://link.springer.com/journal/107062022-01-02hj2021Mining Engineerin

Find the Others: a colorful story about sonder and discovery

\u27Find the Others\u27 tells the story of Benjamin and Clarice, two people who look to find meaning in their monotonous occupations and superficial relationships, only discover something deeper in each other, that reveals a piece of the foggy world they live in

Perianal abscess leading to subcutaneous emphysema and septic shock with multi-organ failure: A case report

Management of benign anorectal conditions like abscesses and hemorrhoids is usually uneventful. However, complicated perianal abscesses can result in severe sepsis and septic shock, even death. Hereby, we report a case of a 30-year-old male with a perianal abscess who underwent incision and drainage and later developed abdominal subcutaneous emphysema with septic shock and finally death. Therefore, neglecting appropriate perioperative care including empirical antibiotics in such patients can have devastating complications

Structural insights into electric field induced polarization and strain responses in K0.5_{0.5}Na0.5_{0.5}NbO3_3 modified morphotropic phase boundary compositions of Na0.5_{0.5}Bi0.5_{0.5}TiO3_3 -based lead-free piezoelectrics

K0.5Na0.5NbO3 (KNN)-modified morphotropic phase boundary (MPB) compositions of the two Na$_{0.5}$Bi$_{0.5}$TiO$_3$-based lead-free piezoelectrics, namely, 0.94Na$_{0.5}$Bi$_{0.5}$TiO$_3$−0.06BaTiO$_3$ (NBT-6BT) and 0.80Na$_{0.5}$Bi$_{0.5}$TiO$_3$−0.20K$_{0.5}$Bi$_{0.5}$TiO$_3$ (NBT-20KBT) are model systems exhibiting large (>0.4%) electric-field-driven strain. There is a general perception that (i) increasing KNN concentration monotonically weakens the direct piezoelectric response $(d_{33})$, and (ii) maximum electrostrain occurs when KNN pushes the system in the fully ergodic relaxor state. We have examined these issues using various complementary techniques involving electrostrain, piezoelectric coefficient $(d_{33})$, ferroelectric switching-current measurements, and field-driven structural studies on the global and local scales using laboratory and synchrotron x-ray diffraction, neutron powder diffraction, and Eu$^{+3}$ photoluminescence techniques. Our investigations revealed the following important features: (i) In the low-concentration regime, KNN induces a tetragonal ferroelectric distortion, which improves the weak signal piezoresponse. (ii) Beyond a threshold concentration, in-phase octahedral tilt sets in and weakens the long-range ferroelectric order to partially stabilize an ergodic state. (iii) The maximum electrostrain (∼0.6%) is achieved in the mixed (nonergodic + ergodic) state. (iv) The mixed state invariably exhibits a less-known phenomenon of field-driven ferroelectric-to-relaxor transformation during bipolar field cycling. (v) The enhanced electrostrain in the mixed state is associated with the electric field increasing the correlation lengths of the short-ranged tetragonal and rhombohedral ferroelectric regions without overall transformation of one phase to the other. We summarize the findings of this work in a comprehensive electric field composition (E-x) phase diagram. The findings reported here are likely to be true for other NBT-based MPB systems