scholarly journals Adapting the Powered Roof Support to Diverse Mining and Geological Conditions

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 405 ◽  
Author(s):  
Dawid Szurgacz ◽  
Jarosław Brodny
Keyword(s):  
Impact Load ◽  
Mining Industry ◽  
Operating Conditions ◽  
Service Workers ◽  
Basic Task ◽  
Geological Conditions ◽  
Control System Model ◽  
And Control ◽  
Design And Testing ◽  
Roof Support

A powered roof support is one of the most important machines of a longwall system. Its basic task is to ensure the safety and continuity of the mining process. The conditions of coal mining process are constantly changing and have significantly deteriorated in recent years, which in turn has also resulted in a significant increase in the requirements for mining support. As a result, it is necessary to develop an appropriate methodology that will facilitate the design and testing process of a power roof support as well as will help to select a roof support adjusted to given conditions. The article presents such a methodology. It is based on forecasted load impacting on a roof support, tests covering selected systems and elements of the section as well as legal conditions regarding the admission of the roof support to operation. This idea was developed in the form of a procedure that, by combining the three areas, should support the decision-making process in the case of different underground conditions. In terms of the expected load impacting on the support, the research team identified the most dangerous phenomena occurring in the rock mass that can generate these loads. Stand tests included impact load and permanent clamping of an excavation. The element that significantly impacts the safety of the support operation is a hydraulic leg, and therefore it was tested together with the safety system and the control system. Model tests were also carried out for the system with a safety valve. The developed concept takes into account legal conditions, which should include test results and different support operating conditions in a more flexible way. The main purpose of the work was to develop a comprehensive methodology for testing and assessing the possibility of using a powered roof support for given mining and geological conditions based on an analysis of safety and control systems. The presented approach is undoubtedly new and original, and can be widely used. It enables better adaptation of the support to given conditions. It also fits the research and activities designed to minimize the presence of miners or service workers in hazardous underground exploitation zones and to improve efficiency and boost sustainable development of the mining industry.

Overview of Path-Planning and Obstacle Avoidance Algorithms for UAVs: A Comparative Study

2018 ◽  
Vol 06 (02) ◽  
pp. 95-118 ◽  
Author(s):  
Mohammadreza Radmanesh ◽  
Manish Kumar ◽  
Paul H. Guentert ◽  
Mohammad Sarim
Keyword(s):  
Path Planning ◽  
Comparative Study ◽  
Operating Conditions ◽  
Computational Time ◽  
Safe Operation ◽  
Sense And Avoid ◽  
Planning Algorithms ◽  
And Control ◽  
Global And Local ◽  
Further Development

Unmanned aerial vehicles (UAVs) have recently attracted the attention of researchers due to their numerous potential civilian applications. However, current robot navigation technologies need further development for efficient application to various scenarios. One key issue is the “Sense and Avoid” capability, currently of immense interest to researchers. Such a capability is required for safe operation of UAVs in civilian domain. For autonomous decision making and control of UAVs, several path-planning and navigation algorithms have been proposed. This is a challenging task to be carried out in a 3D environment, especially while accounting for sensor noise, uncertainties in operating conditions, and real-time applicability. Heuristic and non-heuristic or exact techniques are the two solution methodologies that categorize path-planning algorithms. The aim of this paper is to carry out a comprehensive and comparative study of existing UAV path-planning algorithms for both methods. Three different obstacle scenarios test the performance of each algorithm. We have compared the computational time and solution optimality, and tested each algorithm with variations in the availability of global and local obstacle information.

scholarly journals Exploring the challenges associated with the greening of supply chains in the South African manganese and phosphate mining industry

2014 ◽  
Vol 8 (1) ◽  
Author(s):  
R.I. David Pooe ◽  
Khomotso Mhelembe
Keyword(s):  
Supply Chain ◽  
South African ◽  
Environmental Governance ◽  
Mining Industry ◽  
Monitoring And Control ◽  
The South ◽  
Phosphate Mining ◽  
Phosphate Industry ◽  
Management Recommendations ◽  
And Control

As with most mining activities, the mining of manganese and phosphate has serious consequences for the environment. Despite a largely adequate and progressive framework for environmental governance developed since 1994, few mines have integrated systems into their supply chain processes to minimise environmental risks and ensure the achievement of acceptable standards. Indeed, few mines have been able to implement green supply chain management (GrSCM). The purpose of this article was to explore challenges related to the implementation of GrSCM and to provide insight into how GrSCM can be implemented in the South African manganese and phosphate industry. This article reported findings of a qualitative study involving interviews with 12 participants from the manganese and phosphate industry in South Africa. Purposive sampling techniques were used. Emerging from the study were six themes, all of which were identified as key challenges in the implementation of GrSCM in the manganese and phosphate mining industry. From the findings, these challenges include the operationalisation of environmental issues, lack of collaboration and knowledge sharing, proper application of monitoring and control systems,lack of clear policy and legislative direction, the cost of implementing GrSCM practices, and the need for strong leadership and management of change. On the basis of the literature reviewed and empirical findings, conclusions were drawn and policy and management recommendations were accordingly made.

Experimental Investigation on the Rubbing Process of Labyrinth Seals Considering the Material Combination

2020 ◽  
Author(s):  
Lisa Hühn ◽  
Oliver Munz ◽  
Corina Schwitzke ◽  
Hans-Jörg Bauer
Keyword(s):  
Turbine Blades ◽  
Design Guidelines ◽  
Operating Conditions ◽  
Contact Forces ◽  
Experimental Investigations ◽  
Process Data ◽  
Labyrinth Seals ◽  
Material Combination ◽  
Higher Temperature ◽  
And Control

Abstract Labyrinth seals are used to prevent and control the mass flow rate between rotating components. Due to thermally and mechanically induced expansions during operation and transient flight maneuvers, a contact, the so-called rubbing process, between rotor and stator cannot be excluded. A large amount of rubbing process data concerning numerical and experimental investigations is available in public literature as well as at the Institute of Thermal Turbomachinery (ITS). The investigations were carried out for different operating conditions, material combinations, and component geometries. In combination with the experiments presented in this paper, the effects of the different variables on load due to rubbing are compared, and discussed with the focus lying on the material combination. The influence of the material on the loads can be identified as detailed as never before. For example, the contact forces in the current experiments are higher due to a higher temperature resistance of Young’s modulus. The analysis will also be based on the rubbing of turbine blades. Design guidelines are derived for labyrinth seals with improved properties regarding tolerance of rub events. Based on the knowledge obtained, guidelines for designing reliable labyrinth seals for future engines are discussed.

Artificial Neural Networks Used As a Rule Selector for Fuzzy Logic Controllers

1993 ◽  
Author(s):  
Shou-Heng Huang ◽  
Ron M. Nelson
Keyword(s):  
Fuzzy Logic ◽  
Fuzzy Logic Controller ◽  
Absolute Error ◽  
Operating Conditions ◽  
Delta Rule ◽  
Rule Sets ◽  
Artificial Neural ◽  
Artificial Neural Network Ann ◽  
Set Up ◽  
And Control

Abstract A feedforward, three-layer, partially-connected artificial neural network (ANN) is proposed to be used as a rule selector for a rule-based fuzzy logic controller. This will allow the controller to adapt to various control modes and operating conditions for different plants. A principal advantage of an ANN over a look up table is that the ANN can make good estimates to fill in for missing data. The control modes, operating conditions, and control rule sets are encoded into binary numbers as the inputs and outputs for the ANN. The General Delta Rule is used in the backpropagation learning process to update the ANN weights. The proposed ANN has a simple topological structure and results in a simple analysis and relatively easy implementation. The average square error and the maximal absolute error are used to judge if the correct connections between neurons are set up. Computer simulations are used to demonstrate the effectiveness of this ANN as a rule selector.

Performance Definitions for Three-Fluid Heat and Moisture Exchangers

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Mohamed R. H. Abdel-Salam ◽  
Robert W. Besant ◽  
Carey J. Simonson
Keyword(s):  
Moisture Transfer ◽  
Operating Conditions ◽  
Air Cooling ◽  
Heat And Moisture Exchanger ◽  
Moisture Exchanger ◽  
Heat And Moisture Exchangers ◽  
Overall Performance ◽  
Liquid Heat ◽  
Heat And Moisture ◽  
Design And Testing

This paper presents performance definitions for calculating the overall effectiveness of three-fluid heat and moisture exchangers. The three-fluid heat and moisture exchanger considered in this paper is a combination of a liquid-to-liquid heat exchanger for heat transfer between a desiccant solution and a refrigerant and an energy exchanger for heat and moisture transfer between desiccant solution and air streams. The performance definitions presented in this paper are used to calculate the overall sensible and latent effectivenesses of a three-fluid heat and moisture exchanger, which has been tested under air cooling and dehumidifying operating conditions in a previous work (Abdel-Salam et al., 2016, “Design and Testing of a Novel 3-Fluid Liquid-to-Air Membrane Energy Exchanger (3-Fluid LAMEE),” Int. J. Heat Mass Transfer, 92, pp. 312–329). The effectiveness of this three-fluid heat and moisture exchanger is compared when calculated using the traditional energy exchanger effectiveness equations and the overall performance definitions. Results show that the overall performance definitions provide effectiveness values that are less sensitive to changes in the inlet refrigerant temperature and therefore are more generally applicable for energy exchanger design than the traditional effectiveness equations used in the literature.

scholarly journals Mathematical Modelling and Control of a Two-Wheeled PUMA-LikeVehicle

2016 ◽  
Vol 6 (2) ◽  
pp. 11 ◽  
Author(s):  
Khaled M Goher
Keyword(s):  
Mathematical Modelling ◽  
Sliding Mode ◽  
Impact Load ◽  
State Space Model ◽  
Linear Quadratic Regulator ◽  
The Body ◽  
Pole Placement ◽  
General Motors ◽  
Linear Quadratic ◽  
And Control

<p class="1Body">This paper presents mathematical modelling and control of a two-wheeled single-seat vehicle. The design of the vehicle is inspired by the Personal Urban Mobility and Accessibility (PUMA) vehicle developed by General Motors® in collaboration with Segway®. The body of the vehicle is designed to have two main parts. The vehicle is activated using three motors; a linear motor to activate the upper part in a sliding mode and two DC motors activating the vehicle while moving forward/backward and/or manoeuvring. Two stages proportional-integral-derivative (PID) control schemes are designed and implemented on the system models. The state space model of the vehicle is derived from the linearized equations. Controller based on the Linear Quadratic Regulator (LQR) and the pole placement techniques are developed and implemented. Further investigation of the robustness of the developed LQR and the pole placement techniques is emphasized through various experiments using an applied impact load on the vehicle.</p>

scholarly journals Investigating the use of knowledge management as a management tool in the mining industry

2016 ◽  
Vol 14 (1) ◽  
pp. 176-182 ◽  
Author(s):  
Dinko Herman Boikanyo ◽  
Ronnie Lotriet ◽  
Pieter W. Buys
Keyword(s):  
Knowledge Management ◽  
Business Performance ◽  
Mining Industry ◽  
Management Tool ◽  
Transfer Of Knowledge ◽  
Planning And Control ◽  
Research Population ◽  
And Control ◽  
Use Of Knowledge ◽  
Structured Questionnaire

The main objective of this research study is to investigate the extent to which knowledge management is used within the mining industry. Knowledge management includes the identification and examination of available and required knowledge and the subsequent planning and control of actions to develop knowledge assets to accomplish organizational objectives. A structured questionnaire is used for the study. A total of 300 mines were randomly selected from a research population of mining organizations in South Africa, Africa and globally. The respondents were all part of senior management. A response rate of 64% was achieved. A significant number of respondents indicates that there is no transfer of knowledge about the best practices within their organizations. Some of the participants indicate that their organizations do not have the required technical infrastructure to enable knowledge sharing whilst some agree that the culture in their organizations is not conducive to the sharing of knowledge. A statistically and practically significant positive relationship with a large effect is found between the construct of knowledge management and perceived business performance. The mining organizations in Africa are ranked the lowest in terms of applications of knowledge management principles

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