Microplastics have become so pervasive that they seem to be present all around us due to the significant environmental threat they pose. Microplastic pollutants have become an issue as global plastic manufacturing has increased. Microplastics are plastic wastes with particulates less than 5 mm in size that are absorbed by sediment, water, the atmosphere, and living beings before affecting health. Moreover, there is a shortage of knowledge on the distribution, sources, toxic effects, analytical techniques, and removal technologies of microplastics. This review examines the distribution and global abundance of microplastics in aquatic and terrestrial environments, analytical methods, remediation technologies, and health risks. The following are included in this review article: (1) sampling, extraction, and analysis techniques for microplastics in sediment, water, and salt; (2) the source, global distribution, and concentration of microplastics; (3) toxicity and consequences of microplastics on human health; and (4) several methods for removing microplastics, grouped into three categories: engineered, biopolymer, and bioengineered approaches. The worldwide distribution, identification, toxic effects, and remediation technology of microplastics will benefit greatly from this review.
A methodology is proposed to develop an optimization model to understand the impact of transporting minerals, from mines to the final destination, on air quality. Recently, there has been increasing concern about the combined effects of multiple activities over many years, and the regional environmental changes brought about by a single project. Environmental issues in the iron ore industry have highlighted the need to broaden the cumulative impact assessment. In this study, we simulated the optimal routes and quantity of materials needed to meet the destination plant demand based upon environment constraints (level of air pollution), as well as the cost of transportation and availability of materials. Multiple scenarios were developed to analyse the effects of changes in routes, alternative transport system (or multi-modal split), traffic congestion, and the cumulative impacts on air quality. The air quality impact zones of the study area were demarcated using a GIS technique. The expected outcome of the study is the selection of a suitable transport system for a particular site with the least impact on air quality, including the transportation route, relative to the minimum cost of transportation of the minerals from the mines to their final destination. The proposed methodology is evaluated with a case study.
The present investigation aims to analyze the anisotropy behavior of 8mm thick rolled plate of duplex stainless steel AISI 2205. The study aims to connect the importance of anisotropy properties with fusion welding to achieve the optimal mechanical properties of the weldment by justifying suitable direction for welding. An outcome of the investigation implies that duplex stainless steel exhibits maximum impact toughness in the longitudinal direction i.e. rolling direction when compared to transverse and diagonal directions. Further, the existence of significant directionality was confirmed by analyzing the tensile behavior which gives greater tensile strength in the transverse direction and higher amount of elongation and better formability in the longitudinal direction. The present work was extended by fabricating the weldment using gas tungsten arc welding by keeping the welding direction perpendicular to the rolling direction of a plate. Microstructure and the mechanical properties of the weld were assessed and compared with the behavior of its parent metal.
In the present investigation, an attempt has been made to enhance the surface quality of austenitic stainless steel 316L and duplex stainless steel 2205 through shot peening process. The study mainly focuses the surface morphology, microstructural changes, surface roughness and microhardness of the peened layers. Metallography analysis was carried out and compared with the unpeened surface characteristics. As result of peening process, surface recrystallization was achieved on the layers of the peened samples. It was found that shot peening plays significant role in enhancing the surface properties of 316L and 2205. Particularly it has greater influence on the work hardening of austenitic stainless steel than the duplex stainless steel due to its more ductility nature under the investigated shot peening parameters. The findings of the present study will be useful with regard to the enhancement of surface texture achieved through peening.
In this investigation, analysis of surface topography on Duplex Stainless Steel (DSS) AISI 2205 was carried out under the shot peened and various machined conditions. The surface profiles of the shot peened, polished, milled, ground and as received conditions were compared in micron level. In order to study the influence of shot peening on the profile of surface roughness, DSS samples were peened using S390 shots for different durations. Severe Plastic Deformation (SPD) was observed on the surface of DSS due to peening. Also, peening has more effect on the austenite phases than the ferrite phases on DSS surface. The shot peened surface profiles obtained using S390 shots offer better topography as compared with the other machined and as received surface conditions. As a part of the study, the effect of dual shot peening was inspected by peening the surface using two shots which introduce lots of micro peaks and valleys on the surface of DSS.
The paper approaches the applicability of operational research techniques in transportation of iron ore from multi location mines to single destination beneficiation plant. The mining industry facing environment problems related to transportation are not being adequately addressed by existing research programs. The paper focuses on air quality impacts due to iron ore transportation from mines to destination plant. Also discusses on selection of suitable mode of system for existing site condition and their environmental loads around the periphery of site and along the material conveying path. The research work illustrates the importance of implementation of transportation impact assessment for proposed projects to get clearance from authorities. In this paper, the transportation routes from the consented mines to the destination plant were optimized with the constraints of less pollution and cost effective by the use of optimization software.
The application of a routine high resolution microseismic monitoring system installed in an opencast coal mine for monitoring highwall slope failures is discussed. A PC based microseismic network consisting of geophones, data loggers, GPS synchronization and Ethernet antennas for wireless communication is employed to study the impact of induced seismicity on the slope failures in real time. The study aimed to understand the rock mass response to mining induced seismicity from the behavior of seismic events within rock mass. The level of induced seismicity due to underground excavation is determined from the seismic source parameters such as locations, magnitude, and seismic energy. The status of the slope is assessed by the quantification of the microseismic events. The understanding of spatial and temporal distribution of the seismic events within the mining district correlated well with the existing geological structures and the excavation sequence. The application of microseismic system in the opencast mine has not only yielded confident results, but also marked as an effective tool for continuous monitoring of seismicity on the deep opencast slopes for mitigating the seismic risks and hazard management.
This paper outlines the results obtained from real time microseismic monitoring of an opencast coal mine in South India. The objective of the study is to investigate the stress changes within the rockmass along the slope due to underground mine development operation and their impact on the stability of the highwall slope. The installed microseismic systems recorded the seismic triggerings down to −2 moment magnitude. In general, most of the events recorded during the monitoring period are weak in seismic energy. The study adopts a simple and more reliable tool to characterize the seismically active zone for assessing the stability of the highwall in real time. The impact of underground working on the slope is studied on the basis of the seismic event impact contours and seismic clusters. During the monitoring period, it is observed that the intensity of the overall microseismic activity along the slope due to the mine development operations did not cause any adverse impact on the highwall stability.
An efficient mine management system demand constant attention of mine managers on the key performance indicators like production targets, equipment status, condition of haul roads, safety etc.. There is a wealth of information generated during day to day working of the mine. The success of a mining enterprise is a function of reliability of accumulated information and decision making on the basis of such information. In the present paper a computerized mine operations management system developed for a large opencast mine making use of the potential benefits of geographical information systems, real time kinematic global positioning systems and a communication network to improve the overall efficiency of the mine is presented.