scholarly journals Increasing Labor Efficiency Repairing Metal Structures of Heavy-Duty Quarry Machinery

2019 ◽  
Vol 105 ◽  
pp. 03005
Author(s):  
Michael Drygin ◽  
Nikolai Kuryshkin
Keyword(s):  
Fatigue Cracks ◽  
Coal Mines ◽  
Repair Process ◽  
Specific Rate ◽  
Metal Structures ◽  
Industrial Experiment ◽  
Repair Processes ◽  
Spring Plate ◽  
Dump Trucks ◽  
Open Cast

Supporting metal structures of large dump trucks at open cast coal mines function under exposure to alternating cyclic load. Fatigue cracks that appear there require timely maintenance welding. Organization of repair processes is multivariant; it can be performed either by the enterprise (open cast coal mine) efforts or by special repair units. An industrial experiment carried out at Permyakovskiy and Prokopyevskiy open cast coal mines in Kuzbass has shown that type of large dump trucks’ repair works organization influences significantly process efficiency. Repair welding by enterprise efforts is the most non-productive compared to other types of repair process organization. Its specific rate is 37 per cent lower than in comparison with unstructured welding and 2.2 times lower in comparison with structured metal sheet replacement and structured welding. Structuring repair processes allows to increase their efficiency by 30...40 per cent on average. Structured replacement of the spring plate is the most productive type of metal structure repair process organization. Comparison of maintenance measurement results in accordance with Unified Norms and Prices collected book with the results obtained from the industrial experiment showed that calculation methods give underestimated values of repair processes’ specific rate.

Air quality at open-cast coal mining regions at Hunter Valley, Australia and Ramagundam, India

2021 ◽  
Author(s):  
Harsh Kamath ◽  
Chanchal Chauhan ◽  
Sameer Mishra ◽  
Aariz Ahmed ◽  
Raman Srikanth
Keyword(s):  
Power Plants ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Meteorological Data ◽  
Thermal Power ◽  
Coal Mines ◽  
Export Market ◽  
P Value ◽  
Open Cast ◽  
Monitoring Stations

<p>The upper Hunter Valley region in New South Wales (NSW), Australia has several open-cast coal mines, which supply coal to two large thermal power plants (TPPs) in the area, beside the export market. Long-term Particulate Matter (PM) pollutants and meteorological measurements are recorded by a network of 13 NSW government-owned continuous monitoring stations in the upper Hunter Valley region. The Ramagundam area in the state of Telangana, India has similar pollution source characteristics (coal mines and TPPs), but PM pollutant measurements are largely carried out with manual monitoring stations at 24-hour intervals, not more than twice a week. As the coal and overburden excavation from open-cast coal mines and stack emissions from TPPs lead to local PM pollution, we have used MODIS-MAIAC Aerosol Optical Depth (AOD) at 550 nm and Normalized Difference Vegetation Index (NDVI) along with the local meteorological data such as ambient temperature, relative humidity, wind speed and direction to model PM10 and PM2.5 at the upper Hunter Valley and Ramagundam regions. Our model can explain about 60% of variation in PM10 (p-value < 0.0001), while a similar model is able to explain about 75% of the variation in the PM2.5 (p-value < 0.0001). We will extend our model results from Hunter Valley to Ramagundam area and comment on the potential of using geospatial products such as AOD as a proxy to ground-based pollution measurements in developing countries such as India, where pollution data is scarce.</p>

scholarly journals Performance Evaluation of a Carbon Nanotube Sensor for Fatigue Crack Monitoring of Metal Structures

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4383
Author(s):  
Shafique Ahmed ◽  
Thomas Schumacher ◽  
Erik T. Thostenson ◽  
Jennifer McConnell
Keyword(s):  
Fatigue Crack ◽  
Carbon Nanotube ◽  
Crack Initiation ◽  
Crack Propagation ◽  
Real Time ◽  
False Positive ◽  
Fatigue Cracks ◽  
Fatigue Crack Initiation ◽  
Resistance Change ◽  
Metal Structures

This article describes research that investigated the ability of a carbon nanotube (CNT) sensor to detect and monitor fatigue crack initiation and propagation in metal structures. The sensor consists of a nonwoven carrier fabric with a thin film of CNT that is bonded to the surface of a structure using an epoxy adhesive. The carrier fabric enables the sensor to be easily applied over large areas with complex geometries. Furthermore, the distributed nature of the sensor improves the probability of detecting crack initiation and enables monitoring of crack propagation over time. Piezoresistivity of the sensor enables strains to be monitored in real time and the sensor, which is designed to fragment as fatigue cracks propagate, directly measures crack growth through permanent changes in resistance. The following laboratory tests were conducted to evaluate the performance of the sensor: (1) continuous crack propagation monitoring, (2) potential false positive evaluation under near-threshold crack propagation conditions, and (3) crack re-initiation detection at a crack-stop hole, which is a commonly used technique to arrest fatigue cracks. Real-time sensor measurements and post-mortem fractography show that a distinguishable resistance change of the sensor occurs due to fatigue crack propagation that can be quantitatively related to crack length. The sensor does not show false positive responses when the crack does not propagate, which is a drawback of many other fatigue sensors. The sensor is also shown to be remarkably sensitive to detecting crack re-initiation.

Are open-cast coal mines casting a shadow on the Indian environment?

2008 ◽  
Vol 30 (4) ◽  
pp. 441-459 ◽  
Author(s):  
Urmila Jha-Thakur ◽  
Thomas Fischer
Keyword(s):  
Coal Mines ◽  
Open Cast

scholarly journals Assessing Sustainability Impact of Autonomous Haul System in Indonesian Open Pit Coal Mining Company

2021 ◽  
Vol 3 (4) ◽  
pp. 48-53
Author(s):  
Yonta Wasfadhita ◽  
Gembong Baskoro ◽  
Eka Budiarto ◽  
Dena Hendriana ◽  
Henry Nasution
Keyword(s):  
Human Factors ◽  
Coal Mining ◽  
Coal Mines ◽  
Open Pit ◽  
Mining Company ◽  
Sustainability Index ◽  
The Social ◽  
The World ◽  
Dump Trucks ◽  
Haul Truck

Autonomous Haul System (AHS) has been widely developed in the world since 2007. The main objective of AHS is to eliminate human factors, so that AHS productivity is much higher compared to manned dump trucks. The use of AHS in Indonesia will impact the sustainability index of open pit coal mines. Implementation AHS will affect with slightly higher sustainability index than manned haul trucks, AHS sustainability index is 78,712 and manned haul truck is 74,966. However, there are two sustainability dimensions when using AHS will go decrease, those dimensions are the social and economic dimensions, and AHS will be increasing sustainability index for Ecology, Legal dan Infrastructure Technology.

Effects of Metabolites of Bacteria Bacillus SP. from Permafrost on Speed Repair of Skin Wound

10.12737/7269 ◽  
2014 ◽  
Vol 21 (4) ◽  
pp. 53-61 ◽  
Author(s):  
Бажин ◽  
A. Bazhin ◽  
Калёнова ◽  
L. Kalenova ◽  
Новикова ◽  
...  
Keyword(s):  
Immune System ◽  
Repair Process ◽  
Scar Tissue ◽  
Skin Wound ◽  
Regenerative Process ◽  
Skin Defect ◽  
Bacillus Sp ◽  
Repair Processes ◽  
Stage Of Development ◽  
Cell Immunity

Fossil bacteria are evolutionarily valuable forms of life. In permafrost conditions for a very long time, bacteria can develop a unique repair mechanisms of structural and functional defects. In the experiment on mice of BALB/c it was revealed the presence of high reparative capacity in fossil bacteria strain MG8 Bacillus sp., isolated from samples of relict permafrost, and their metabolic products – metabolites that can be delegated to other living systems. Ability to regulate reparative processes in macroorganism shows in MG8 in the doses less than 20×1103 microbial cells and topically on the wound surface. The “thermal" metabolites, produced by culturing the bacteria at 37°C, are leaders modulation of repair processes in healing skin blemishes. Local application on the wound ointment with "heat" metabolites allows to accelerate by 30% the process of reparation relative to placebo, by 20% – relative to the medicinal product "Solcoseryl" and by 10% – faster than under the influence of bacteria. Dynamics of morphogenetic processes in the healing of skin defect under MG8 bacteria effect and their metabolites is correlated with the dynamics of immune system activity. The sequence of changes in the activity of various components of the immune system (cellular factors inherent immunoresistance – cell immunity humoral immunity) corresponds to the stage of development of the repair process (damage – inflammation – recovery). Mechanisms of regulation of repair processes in the immune system consistent with the general laws regulating the inflammatory process and changes in waves: the predominant increase in the activity of pro-inflammatory mechanisms replaced predominant anti-inflammatory mechanisms of increased activity of the immune system. Using strain MG8 metabolites allows to optimize regenerative process, to reduce time of wound contraction and the formation of scar tissue, to full restore of the coat, so they can be modulators of the wound process, with a predominance of regeneration mechanisms

scholarly journals A Study on Fusion Repair Process for a Precipitation Hardened IN738 Ni-Based Superalloy

1999 ◽  
Author(s):  
Dae-Young Kim ◽  
Jong-Hyun Hwang ◽  
Kwang-Soo Kim ◽  
Joong-Geun Youn
Keyword(s):  
Optimum Condition ◽  
Laser Welding ◽  
Laser Cladding ◽  
Heat Input ◽  
Arc Welding ◽  
Repair Process ◽  
Gas Tungsten Arc Welding ◽  
Repair Processes ◽  
Gas Tungsten Arc ◽  
Welding Heat Input

Several fusion repair processes such as laser cladding, laser welding and gas tungsten arc welding have been taken into consideration for repairing IN738 precipitation hardened Ni-based superalloy material. Effect of heat input on weld cracking susceptibility has been studied to obtain optimum condition for crack free welds. Variations in cracking susceptibility as a function of welding heat input is discussed with reference to metallurgical characteristics of the welds.

scholarly journals Crack Formation in Metal Structures of Heavy Dump Trucks during Operation at Kuzbass Open Pit Mines

2020 ◽  
Vol 174 ◽  
pp. 03020
Author(s):  
Andrey Pokatilov ◽  
Anastasia Shirokolobova ◽  
Roman Dobrynin ◽  
Andrey Vinidiktov
Keyword(s):  
Crack Formation ◽  
Hydraulic Cylinder ◽  
Open Pit ◽  
Strength Analysis ◽  
Structural Elements ◽  
Open Pit Mines ◽  
Metal Structures ◽  
Dump Trucks ◽  
Housing Component ◽  
Cycles To Failure

The results of crack formation monitoring in metal structures of BelAZ heavy dump trucks during their operation at Kuzbass open-casts are given in the article. Possible causes and areas of the crack-like defects formation during operation of heave dump trucks at depths greater than 300 m are considered. The assembly units and elements of heave dump trucks and the areas of the highest total stresses are determined by solid modeling, strength analysis and monitoring of the condition of metal structures under production conditions. The law of crack length development in the areas of the transaxle-housing component and the fastening of the hydraulic cylinder depending on the number of loading cycles is established. The stresses dependence arising in the structural elements of heavy dump trucks during operation under various loads, on the number of loading cycles to failure, is presented.

Sign in / Sign up

Export Citation Format

Share Document