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Abstrakt

The presented study concerns development of a facial detection algorithm operating robustly in the thermal infrared spectrum. The paper presents a brief review of existing face detection algorithms, describes the experiment methodology and selected algorithms. For the comparative study of facial detection three methods presenting three different approaches were chosen, namely the Viola–Jones, YOLOv2 and Faster-RCNN. All these algorithms were investigated along with various configurations and parameters and evaluated using three publicly available thermal face datasets. The comparison of the original results of various experiments for the selected algorithms is presented.
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Autorzy i Afiliacje

Marcin Ł. Kowalski
1
Artur Grudzien
1
Wiesław Ciurapinski
1

  1. Military University of Technology, Institute of Optoelectronics, gen. Sylwestra Kaliskiego 2, 00-908 Warszawa, Poland

Abstrakt

This paper presents a study on the influence of psychophysical stimuli on facial thermal emissions. Two independent groups of stimuli are proposed to investigate facial changes resulting from human stress and physical exhaustion. One pertains to physical effort while the other is linked to stress invoked by solving a simple written test. Subjects’ face reactions were measured through collecting and analysing long-wavelength infrared images. A methodology for numerical processing of images is proposed. Results of numerical analysis with respect to different facial regions of interest are provided. An automatic deep learning based algorithm to classify specific thermal face patterns is proposed. The algorithm consists of detection of regions of interests as well as numerical analysis of thermal energy emissions of facial parts. The results of presented experiments allowed the authors to associate emission changes in specific facial regions with psychophysical stimulations of the person being examined. This work proves high usability of thermal imaging to capture changes of heat distribution of face as reactions for external stimuli.

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Autorzy i Afiliacje

Jarosław Panasiuk
Piotr Prusaczyk
Artur Grudzień
Marcin Kowalski

Abstrakt

The paper considers the problem of increasing the generalization ability of classification systems by creating an ensemble of classifiers based on the CNN architecture. Different structures of the ensemble will be considered and compared. Deep learning fulfills an important role in the developed system. The numerical descriptors created in the last locally connected convolution layer of CNN flattened to the form of a vector, are subjected to a few different selection mechanisms. Each of them chooses the independent set of features, selected according to the applied assessment techniques. Their results are combined with three classifiers: softmax, support vector machine, and random forest of the decision tree. All of them do simultaneously the same classification task. Their results are integrated into the final verdict of the ensemble. Different forms of arrangement of the ensemble are considered and tested on the recognition of facial images. Two different databases are used in experiments. One was composed of 68 classes of greyscale images and the second of 276 classes of color images. The results of experiments have shown high improvement of class recognition resulting from the application of the properly designed ensemble.
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Autorzy i Afiliacje

Robert Szmurło
1
ORCID: ORCID
Stanislaw Osowski
2
ORCID: ORCID

  1. Faculty of Electrical Engineering, Warsaw University of Technology, Koszykowa 75, 00-662 Warszawa, Poland
  2. Faculty of Electronic Engineering, Military University of Technology, gen. S. Kaliskiego 2, 00-908 Warszawa, Poland

Abstrakt

A significant problem with the effective functioning of the hard-coal mining industry, especially in relation to mining enterprises and mines located in the Upper Silesian Coal Basin, are the high costs of mining. This is due to many reasons, among which, an important aspect is the ineffective use of the working time of mining faces. The unsatisfactory use of working time caused by unplanned shutdowns of mining faces is a significant reason for the fact that the use of the production potential of the expensive, modern mechanized systems built in them, with the production capacity of around 1,000–1,500 tons per hour, is relatively small – the average daily volume of mining from a longwall working is most often around 3,000 tonnes or even slightly less. A significant reason for this is the occurrence of a large number of interruptions in the continuity of their work, which is mainly caused by equipment failures, the impact of unfavorable geological and mining conditions or technological shutdowns.
The article deals with the problem of the unsatisfactory level of the effective use of working time in mining faces (longwalls) in Polish hard-coal mines. The main reason for this is the occurrence of a large number of unplanned stops and interruptions, sometimes lasting several days. Their elimination or at least reduction would significantly contribute to the improvement of the existing situation. The condition for this, however, is reliable analyses aimed at detailed the identification of their causes. It was proposed to use three methods – the analytic hierarchy process (AHP), the development of the Pareto-Lorenz diagram and the 5 Whys method. Examples of their practical application are also presented.
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Autorzy i Afiliacje

Patrycja Bąk
1
ORCID: ORCID
Marian Turek
2
ORCID: ORCID

  1. AGH University of Science and Technology, Kraków, Poland
  2. Central Mining Institute, Katowice, Poland

Abstrakt

Face Sketch Recognition (FSR) presents a severe challenge to conventional recognition paradigms developed basically to match face photos. This challenge is mainly due to the large texture discrepancy between face sketches, characterized by shape exaggeration, and face photos. In this paper, we propose a training-free synthesized face sketch recognition method based on the rank-level fusion of multiple Image Quality Assessment (IQA) metrics. The advantages of IQA metrics as a recognition engine are combined with the rank-level fusion to boost the final recognition accuracy. By integrating multiple IQA metrics into the face sketch recognition framework, the proposed method simultaneously performs face-sketch matching application and evaluates the performance of face sketch synthesis methods. To test the performance of the recognition framework, five synthesized face sketch methods are used to generate sketches from face photos. We use the Borda count approach to fuse four IQA metrics, namely, structured similarity index metric, feature similarity index metric, visual information fidelity and gradient magnitude similarity deviation at the rank-level. Experimental results and comparison with the state-of-the-art methods illustrate the competitiveness of the proposed synthesized face sketch recognition framework.
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Autorzy i Afiliacje

Sami Mahfoud
1
ORCID: ORCID
Abdelhamid Daamouche
1
ORCID: ORCID
Messaoud Bengherabi
2
ORCID: ORCID
Abdenour Hadid
3
ORCID: ORCID

  1. University M’Hamed Bougara of Boumerdes, Institute of Electrical and Electronic Engineering, Laboratory of Signals and Systems, Boumerdes, 35000, Algeria
  2. Center for Development of Advanced Technologies, P.O. Box 17 Baba-Hassen 16303, Algiers, Algeria
  3. Sorbonne University Abu Dhabi, Sorbonne Center for Artificial Intelligence, Abu Dhabi, UAE

Abstrakt

The article presents experiments in realistic modelling of facial expressions using volume morphing. The experiments use a variable number of points and face features. As the results are shown meshes deviations (between goal mesh and morphed shape). Experiments have shown that it is impossible to carry out a fully realistic morphing based on existing software. At the same time, even imperfect morphing allows you to show the expected emotional facial expression.

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Autorzy i Afiliacje

Przemysław Kowalski

Abstrakt

Since March 11, 2020, the global community has faced the challenges of the COVID-19 pandemic. In response, numerous countries, including the Republic of Lithuania, mandated the wearing of face masks to curb the virus’s spread. Yet, a section of the Lithuanian populace resisted this move, voicing concerns about the inconvenience of mask-wearing and potential privacy infringements. These concerns endured, even amidst debates on the masks’ effectiveness. This article explores how the Lithuanian public responded to mask-wearing protocols during the pandemic. Survey analysis highlighted a troubling trend: many individuals dispose of face masks with their regular trash, often without proper packaging. Most masks are sourced from pharmacies or are provided by employers and are typically thrown away after just one day of use. The data underscores a significant knowledge gap in correct mask disposal, as a significant portion ends up mingled with general household waste, without proper containment. Moreover, many people keep used masks in pockets or bags. Notably, during the pandemic, an estimated 2 mln adult Lithuanians may have generated roughly 15.24 Mg of hazardous plastic waste through mask disposal.
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Autorzy i Afiliacje

Laima Cesoniene
1
ORCID: ORCID
Raimonda Simanaviciute
1
Daiva Sileikiene
1
ORCID: ORCID
Dawid Bedla
2
ORCID: ORCID

  1. Vytautas Magnus University, Agriculture Academy, Faculty of Forest Sciences and Ecology, Studentų St 11, Akademija, Kaunas, Lithuania
  2. University of Agriculture in Krakow, Department of Ecology, Climatology and Air Protection, Krakow, Poland

Abstrakt

The objective of the study was to assess the potential use of optical measuring instruments to determine the minimum chip thickness in face milling. Images of scanned surfaces were analyzed using mother wavelets. Filtration of optical signals helped identify the characteristic zones observed on the workpiece surface at the beginning of the cutting process. The measurement data were analyzed statistically. The results were then used to estimate how accurate each measuring system was to determine the minimum uncut chip thickness. Also, experimental verification was carried out for each mother wavelet to assess their suitability for analyzing surface images.

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Autorzy i Afiliacje

Damian Gogolewski
Włodzimierz Makieła
Łukasz Nowakowski
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Abstrakt

Tunnel construction survey must be necessary to be very quick so that the results can be known as soon as possible. This aim can be achieved through the intelligent positioning method of tunnel excavation face. In this study, the plane parameters of the tunnel cross-section were transformed into the coordinates of the points on the cross-section to realize the automatic transformation of graphic data. According to the theoretical calculation of the lofting point accuracy, the appropriate measurement control network level and measurement accuracy and the appropriate measurement instruments were selected. The fast and intelligent positioning and setting out of tunnel excavation face was realized base on the technology of data communication between computer and measuring instruments. The intelligent positioning method of tunnel excavation face could greatly reduce the time of measurement and positioning, speed up the project progress, reduce the project risk, shorten the construction period and reduce the project cost.
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Bibliografia

[1] K. Rabensteiner, “Automated surveying speeds construction”, Tunnels & Tunnelling, 1996, vol. 28, no. 1, pp. 40–41.
[2] H.E. Bin, “Application of CASIO Measurement Program Assisted by Total Station in Survey of Tunnel Cross-Section”, Tunnel Construction, 2009, vol. 29, no. 1, pp. 120–122.
[3] Z. Lei, “Application of Total Station ’s Surrounding Measurement Function in Highway Survey and Design”, Peak Data Science, 2017, vol. 6, no. 4, pp. 105–107.
[4] L.F. Geng, “Analysis of mechanical properties of full section excavation of single arch four-lane highway tunnel”, Shanxi Architecture, 2009, vol. 2.
[5] Y.H. Deng, “Determination of full section excavation boundary of transition curve tunnel”, Mine Surveying, 2004, vol. 2004, no. 2, pp. 34–36.
[6] W.W. Yan, “Application of CASIO Series Programming Calculator in the Measurement of Tunnel Sections”, Shanxi ence and Technology, 2011, vol. 26, no. 4, pp. 123–124.
[7] W.B. Luo, “The realization of real-time communication between mobile intelligent equipment and total station under net environment”, Surveying and mapping equipment, 2007, vol. 9, no. 4, pp. 42–43.
[8] C.X. Niu, “Construction Survey of Tanba No. 4 Spiral Tunnel on Xiaohe-Ankang Highway”, Tunnel Construction, 2014, vol. 34, no. 2, pp. 163–166, DOI: 10.3973/j.issn.1672-741X.2014.02.013.
[9] L.H. Luo, S.L. Wei, “Application of Surveying Robot in Pipe Jacking Crossing Subway Tunnel Project”, Jiangsu Construction, 2018, vol. 2018, no. 6, pp. 65–66.
[10] W. He, C. Song, B. Du, “Chinese Longest Sea-crossing Metro Tunnel: Wuyuan Bay Station-Liuwudian Station Section of Xiamen Metro Line 3”, Tunnel Construction, 2018, vol. 38, no. 3, pp. 501–505.
[11] Y.X. Hu, Y. Yue, H.D. Zhang, et al., “Application of Gyroscope in Directional Measurement of Long Distance Cross Sea Metro Tunnel”, Urban Geotechnical Investigation & Surveying, 2019, vol. 2019, no. 6, pp. 172–175.
[12] Y. Zhou, S. Wang, M. Xi, et al., “Railway Tunnel Clearance Inspection Method Based on 3D Point Cloud from Mobile Laser Scanning”, Sensors, 2017, vol. 17, no. 9, DOI: 10.3390/s17092055.
[13] W.Wei, “3D Laser scanning technique is applied to the measurement of tunnel section deformation”, Beijing Surveying and Mapping, 2020, vol. 34, no. 4, pp. 561–565.
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Autorzy i Afiliacje

Jiesheng Zhang
1
ORCID: ORCID
Yongzheng Qi
2
ORCID: ORCID

  1. The First Engineering Co., LTD. of CTCE Group, No. 434 Fuyang North Road, Hefei 230041, China
  2. Jiangsu University of Science and Technology, School of Civil Engineering and Architecture, No. 2 Mengxi Road, Zhenjiang 212003, China

Abstrakt

Recent papers and studies over the course of last three years have shown that COVID-19 has a negative impact on the speech communication quality between people. This paper presents an influence analysis of the curvature shape of protective transparent shields on the speech signal. Five shields made of the same material and dimensions but with different curvatures were analyzed, from a completely flat to a very curved shield which has the same shape of curvature at its top and bottom and covers the entire face. The influence of the shield is analyzed with two types of experiments – one using dummy head with integrated artificial voice device, and the other using real speakers (female and male actors). It has been shown that usage of protective shields results in a relative increase in the speech signal level, in the frequency range of around 1000 Hz, compared to the situation when protective shields are not used. The relative increase in speech signal levels for large-curvature shields can be up to 8 dB. The possible causes of this phenomenon have been analyzed and examined.
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Autorzy i Afiliacje

Miloš Bjelic
1
ORCID: ORCID
Miomir Mijic
1
ORCID: ORCID
Tatjana Miljkovic
1
ORCID: ORCID
Dragana Šumarac Pavlovic
1
ORCID: ORCID

  1. School of Electrical Engineering, University of Belgrade Belgrade, Serbia

Abstrakt

Forty years ago Antonina Kłoskowska built up a universal paradigm of three social frames of culture. They included: frame one, i.e. local production of symbolic processes, close to folk culture; frame two — understood as a network of local institutions of culture; frame three — involving a radiation of pan-local centers, in particular a reception of contents transmitted by mass media. A basic sociological criterion of differentiating between these categories includes a type of contact, and adjacency of sender and recipient of symbolic communication. Currently, following years of development of digital means of communication, computer networks and fiber optic technologies, audio-visual systems, mobile telephones, etc. a proposal of frames of culture must be examined again. New media shape new vehicles of expression (e.g. hypertext), but most importantly they inspire specific social relations. Discussion over cultural framework is also triggered by accelerated processes of economic and social transformation, advanced globalization, increase of living standards and dissemination of consumption attitudes, changes in leisure activities of the middle class. In more narrowly understood domain of institutional and professional culture one witnessed the processes of European deregulation and release of culture from state, which in Eastern Europe was accompanied by abolition of censorship and a different model of culture distribution, which is controlled by market and cultural (creative) industry rather than by central government. As a result, the nature of direct communication among people is subject to ongoing transformation. We witness more and more indirect cultural communication (off-line and on-line). Modified and broadened proposal of social frames of culture includes five rather than three paradigms, namely: the culture of indirect communication, the culture of associations and volunteers; the culture of local institutions (public and private), mass culture versus pop culture, cyber-culture, culture of network community.

One has to underline that in the new reality of our civilization we can still use analytic principles of Kłoskowska’s typology. First, we can treat spiritual culture as a phenomenon of autotelic semiosis with pragmatic definition of sign; second, while describing social functioning of culture we can use a sociological criterion of contact and adjacency.

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Autorzy i Afiliacje

Bogusław Sułkowski

Abstrakt

A simple empirical study on the orientation, diameter, and extent of radial fractures (long and short) at the vicinity of the face-perpendicular preconditioned boreholes is described. Homogenous and heterogeneous mining faces were considered when studying the orientation of radial fractures, four and five face-perpendicular preconditioning practices were used to investigate the outspread and diameter of radial fractures from one blasted drill hole to another. Long radial fractures were observed to be developed along the direction of the maximum principal stress and short radial fractures were observed to be developed along the direction of the intermediate principal stress in a homogenous mining face. On the other hand, long radial fractures were observed to be developed along the direction of the intermediate principal stress, while short radial fractures were observed to be developed along the direction of the maximum principal stress when the mining faces subjected to heterogeneous rock mass. The diameters of the radial fractures observed were inconsistent and were not nine times the diameter of the original borehole. Furthermore, the extent of radial fractures from one borehole to another was noted to be gradually improved when the additional of preconditioned borehole was in place. This study maintained that the orientation of radial fractures is mostly controlled by the rock properties, however, extend and the diameters of the radial fractures are controlled by rock properties, the effectiveness of the stress wave and gas pressure and brittleness of the rock mass.

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Autorzy i Afiliacje

Fhatuwani Sengani
Pobierz PDF Pobierz RIS Pobierz Bibtex

Abstrakt

Heat exhaustion of mining environments can cause a significant threat to human health. The existing cooling strategies for the mine face aim to cool the whole face. However, the necessary cooling space for the face is small, with a considerable amount of energy for cooling being wasted. Necessary cooling space is a space occupied by the workers in the face. This study proposed to build a non-homogeneous thermal environment for cost-effective energy savings in the face. An inlet air cooler was laid out in the intake airway to cool the whole face to some extent, and the tracking air cooler was designed to track the worker who constantly moved to improve the thermal environment. The cooling load and air distribution for this cooling strategy were investigated. In addition, the airflow in the face was solved numerically to estimate the cooling effect. The results revealed that an average energy saving of approximately 35% could be achieved. The thermal environment of the necessary cooling space within at least 10 m was significantly improved. This cooling strategy should be taken into account in mine cooling.
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Bibliografia

[1] J.A. Crawford, H.P.R. Joubert, M.J. Mathews, M. Kleingeld, Optimised dynamic control philosophy for improved performance of mine cooling systems. Appl. Therm. Eng. 150, 50-60 (2019). DOI : https://doi.org/10.1016/j.applthermaleng.2018.12.160
[2] Z. Chu, J. Ji, X. Zhang, H. Yan, H. Dong, J. Liu, Development of ZL400 mine cooling unit using semi-hermetic screw compressor and its application on local air conditioning in underground long-wall face. Arch. Min. Sci. 61 (4), 949-966 (2016). DOI: https://doi.org/10.1515/amsc-2016-0063
[3] L. Guo, W. Nie, S. Yin, Q. Liu, Y. Hua, L. Cheng, X. Cai, Z. Xiu, T. Du, The dust diffusion modeling and determination of optimal airflow rate for removing the dust generated during mine tunneling. Build. Environ. 178, 106846 (2020). DOI: https://doi.org/10.1016/j.buildenv.2020.106846
[4] Z. Różański, P. Wrona, J. Sułkowski, J. Drenda, G. Pach, Two stage assessment of thermal hazard in an underground mine. Arch. Min. Sci. 61 (2), 309-322 (2016). DOI: https://doi.org/10.1515/amsc-2016-0023
[5] J. Ji, N. Li, Z. Chang, Y. Fan, L. Ni, Study on heat transfer characteristic parameters and cooling effect of cold wall cooling system in coal mines. Exp. Heat. Transfer. 33 (2), 1-18 (2019). DOI : https://doi.org/10.1080/08916152.2019.1576802
[6] Z.G. Su, Z.A. Jiang, Z.Q. Sun, Study on the heat hazard of deep exploitation in high-temperature mines and its evaluation index. Procedia Earth Planet. Sci. 1, 414-419 (2009). DOI: https://doi.org/10.1016/j.proeps.2009.09.066
[7] A.M. Donoghue, M.J. Sinclair, G.P. Bates, Heat exhaustion in a deep underground metalliferous mine. Occup. Environ. Med. 57, 165-74 (2000).
[8] E.H. Lee, C. Luo, Y.L. Sam, A.C. Roberts, K.W. Kwok, J. Car, C. Soh, G.I. Christopoulos, The underground workspaces questionnaire (UWSQ): Investigating public attitudes toward working in underground spaces. Build. Environ. 153, 28-34 (2019). DOI: https://doi.org/10.1016/j.buildenv.2019.02.017
[9] G . Katavoutas, M.N. Assimakopoulos, D.N. Asimakopoulos, On the determination of the thermal comfort conditions of a metropolitan city underground railway. Sci. Total. Environ. 566, 877-887 (2016). DOI : https://doi.org/10.1016/j.scitotenv.2016.05.047
[10] L.E. Armstrong, R.M. Lopez, Return to exercise training after heat exhaustion. J. Sport Rehab. 16, 182-189 (2007). DOI: https://doi.org/10.1016/j.jsams.2006.11.001
[11] Y. Kasap, The effect of work accidents on the efficiency of production in the coal sector. S. Afr. J. Sci. 107, 77-85 (2011). DOI: https://doi.org/10.4102/sajs.v107i5/6.513
[12] H .S. Li, S.Y. Liu, H.H. Chang, Experimental research on the influence of working parameters on the drilling efficiency. Tunnel. Underground Space Technol. 95, 11 (2020). DOI: https://doi.org/10.1016/j.tust.2019.103174
[13] J.G. Pretorius, M.J. Mathews, P. Maré, M. Kleingeld, J.V. Rensburg, Implementing a DIKW model on a deep mine cooling system. Int. J. Min. Sci. Technol. 29 (2), 319-326 (2019). DOI : https://doi.org/10.3969/j.issn.2095-2686.2019.02.019
[14] N. Szlązak, D. Obracaj, J. Swolkień, K. Piergies, Controlling the distribution of cold water in air cooling systems of underground mines. Arch. Min. Sci. 61 (4), 793-807 (2016). DOI: https://doi.org/10.1515/amsc-2016-0054
[15] C . Jin, X. Bai, Y. An, J. Ni, J. Shen, Case study regarding the thermal environment and energy efficiency of raisedfloor and row-based cooling. Build. Environ. 182, 107110 (2020). DOI : https://doi.org/10.1016/j.buildenv.2020.107110
[16] S. Wang, L. Jin, Z. Han, Y. Li, S. Ou, N. Gao, Z. Huang, Discharging performance of a forced-circulation ice thermal storage system for a permanent refuge chamber in an underground mine. Appl. Therm. Eng. 110, 703-709 (2017). DOI: https://doi.org/10.1016/j.applthermaleng.2016.08.192
[17] B. Nowak, P. Życzkowski, R. Łuczak, Functional dependence of thermodynamic and thermokinetic parameters of refrigerants used in mine air refrigerators. Part 1-refrigerant R407C. Arch. Min. Sci. 62 (1), 55-72 (2017). DOI: https://doi.org/10.1515/amsc-2017-0005
[18] S. Rahnama, P. Sadeghian, P.V. Nielsen, C. Zhang, S. Sadrizadeh, A. Afshari, Cooling capacity of diffuse ceiling ventilation system and the impact of heat load and diffuse panel distribution. Build. Environ. 185, 107290 (2020). DOI: https://doi.org/10.1016/j.buildenv.2020.107290
[19] H . Shi, Q. Chen, Building energy management decision-making in the real world: A comparative study of HVAC cooling strategies. J. Build. Eng. 33, 101869 (2021). DOI: https://doi.org/10.1016/j.jobe.2020.101869
[20] H .X. Guo, K.J. Zhu, C. Ding, L.L. Li, Intelligent optimization for project scheduling of the first mining face in coal mining. Expert Syst. Appl. 37, 1294-1301 (2010). DOI: https://doi.org/10.1016/j.eswa.2009.06.025
[21] T. Ahmad, H.X. Chen, Short and medium-term forecasting of cooling and heating load demand in building environment with data-mining based approaches. Energ. Buildings. 166, 460-76 (2018). DOI : https://doi.org/10.1016/j.enbuild.2018.01.066
[22] P. Guo, C. Chen, Field experimental study on the cooling effect of mine cooling system acquiring cold source from return air. Int. J. Min. Sci. Technol. 23, 453-456 (2013). DOI: https://doi.org/10.1016/j.ijmst.2013.05.008
[23] E. Abdelaziz, R. Saidur, S. Mekhilef, A review on energy saving strategies in industrial sector. Renewable Sustainable Energy Rev. 15, 150-168 (2011). DOI: https://doi.org/10.1016/j.rser.2010.09.003
[24] G .E. du Plessis, L. Liebenberg, E.H. Mathews, Case study: The effects of a variable flow energy saving strategy on a deep-mine cooling system. Appl. Energ. 102, 700-709 (2013). DOI : https://doi.org/10.1016/j.apenergy.2012.08.024
[25] H .L. Hartman, J.M. Mutmansky, R.V. Ramani, Y. Wang, Mine ventilation and air conditioning, 2012 John Wiley & Sons, California. [26] A.W. Homer, Coal mine safety regulation in China and the USA. J. Contemp. Asia. 39, 4-39 (2009).
[27] A.P. Sasmito, J.C. Kurnia, E. Birgersson, A.S. Mujumdar, Computational evaluation of thermal management strategies in an underground mine. Appl. Therm. Eng. 90, 1144-1150 (2015). DOI: https://doi.org/10.1016/j.applthermaleng.2015.01.062
[28] X. Li, H. Fu, Development of an efficient cooling strategy in the heading face of underground mines. Energies 13 (5), 1116 (2020). DOI: https://doi.org/10.3390/en13051116
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Autorzy i Afiliacje

Xian Li
1
ORCID: ORCID
Yaru Wu
1
ORCID: ORCID
Yunfei Zhang
2
ORCID: ORCID

  1. Linyi University, School of Civil Engineering and Architecture, Linyi 276000, P.R. China
  2. Hohai University, College of Civil and Transportation Engineering, Nanjing 210098, P.R. China

Abstrakt

The absolute positions of shearers on advancing coal faces are requisite for providing references for adaptive mining combined with geological models. Common coalmine localization techniques (e.g. UWB, INS, etc.) are not fully applicable to adaptive mining due to their drifting error or the messy environment. The gyro robotic total station (RTS) is versatile and precise in measuring coordinates in coal mines, while its conventional usage is of low automation and poor timeliness, impeding its application on mining faces. This article proposed an automated gyro RTS system for real-time absolute positioning on fully mechanised coal faces. The measuring process was changed to fit mining requirements, and a new state-transferring model was used to automate it. Programs were developed and installed in available instruments, forming a prototype. Field experiments were carried out on a simulative working face, verifying the system’s accuracy and applicability. Results show that the relative positioning error is better than 2.6143×10-4, which meets the demand of advancing faces. The error of the gyro is estimated at 55.5187”, justifying its nominal indicators. To sum up, the automated gyro RTS system proposed in this paper can offer real-time and accurate absolute positions of equipment on working faces, supporting adaptive mining combined with the geological model.
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Autorzy i Afiliacje

Ben Li
1
ORCID: ORCID
Shanjun Mao
1
ORCID: ORCID
Haoyuan Zhang
1
ORCID: ORCID
Xinchao Li
2
ORCID: ORCID
Huazhou Chen
2
ORCID: ORCID

  1. Peking University, Institute of Remote Sensing and Geographic Informat ion System, Beijing 100871, China
  2. Beijing Longruan Technologies Co., Ltd., Beijing 100871, China

Abstrakt

In the current smart tech world, there is an immense need of automating tasks and processes to avoid human intervention, save time and energy. Nowadays, mobile phones have become one of the essential things for human beings either to call someone, connect to the internet, while driving people need mobile phones to receive or make a call, use google maps to know the routes and many more. Normally in cars, mobile holders are placed on the dashboard to hold the mobile and the orientation of the phone needs to be changed according to the driver's convenience manually, but the driver may distract from driving while trying to access mobile phone which may lead to accidents. To solve this problem, an auto adjustable mobile holder is designed in such a way that it rotates according to the movement of the driver and also it can even alert the driver when he feels drowsiness. Image Processing is used to detect the movement of the driver which is then processed using LabVIEW software and NI myRIO hardware. NI Vision development module is used to perform face recognition and servo motors are used to rotate the holder in the required position. Simulation results show that the proposed system has achieved maximum accuracy in detecting faces, drowsiness and finding the position coordinates.
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Autorzy i Afiliacje

Srilatha Madhunala
1
Bhavya Kanneti
1
Priya Anathula
1

  1. Department of ECE, Vardhaman College of Engineering, India
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Abstrakt

Waviness is a parameter used to complete information on the machined surface state. There is little scientific and technical information on the influence exerted by the cutting conditions and the workpiece material hardness on the values of some parameters that define the waviness of milled surface. No works have been identified to present such information for dry high-speed face milling applied to hard steel workpieces. A factorial experiment with four independent variables at three variation levels was planned to model the influence of milling speed, feed, cutting depth, and steel hardness on the total heights of the profile and surface waviness for dry high-speed face milling. Mathematical processing of experimental results was used to identify the power type function and empirical mathematical models. These models highlight the direction of variation and the intensity of influence exerted by the considered input factors on the values of two waviness parameters in the case of dry high-speed face milling of samples made of four hard steels. It has been observed that the increase in steel hardness increases the total heights of the profile and surface waviness. In the case of two types of steel, a good correlation was identified between the values of the total profile waviness height and the total surface waviness height, respectively, using the Pearson correlation coefficient.
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Bibliografia

[1] Vakondios, D., Kyratsis, P., Yaldiz, S., & Antoniadis, A. (2012). Influence of milling strategy on the surface roughness in ball end milling of the aluminum alloy Al7075-T6. Measurement, 45(6), 1480–1488. https://doi.org/10.1016/j.measurement.2012.03.001
[2] Raja, J., Muralikrishnan, B., Fu, S., & Liu, X., (2002). Recent advances in separation of roughness, waviness and form. Precision Engineering, 26(2), 222–235. https://doi.org/10.1016/S0141-6359 (02)00103-4
[3] Clarysse, F., & Vermeulen, M. (2004). Characterizing the surface waviness of steel sheet: reducing the assessment length by robust filtering. Wear, 257(12), 1219–1225. https://doi.org/10.1016/j.wear.2004.04.006
[4] Mezghani, S., & Zahouani, H. (2004). Characterization of the 3D waviness and roughness motifs. Wear, 257(12), 1250–1256. https://doi.org/10.1016/j.wear.2004.04.006
[5] Lingadurai, K., & Shunmugam, M. S. (2006). Metrological characteristics of wavelet filter used for engineering surfaces. Measurement, 39(7) 575–584. https://doi.org/10.1016/j.measurement.2006.02.003
[6] Gogolewski, D., & Makiela, W. (2018). Application of wavelet transform to determine surface texture constituents. In Durakbasa, N. M., Gencyilmaz, M. G. (Eds.). Proceedings of the International Symposium for Production Research 2018, (pp. 224–231). Springer. https://doi.org/10.1007/978-3-319-92267-6_19
[7] Gogolewski, D. (2020). Influence of the edge effect on the wavelet analysis process. Measurement, 152, 107314. https://doi.org/10.1016/j.measurement.2019.107314
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[11] Boryczko, A. (2013). Effect of waviness and roughness components on transverse profiles of turned surfaces. Measurement, 46(1), 688–696. https://doi.org/10.1016/j.measurement.2012.09.007
[12] Wieczorowski, M., Cellary, A., & Majchrowski, R. (2010). The analysis of credibility and reproducibility of surface roughness measurement results. Wear, 269(5-6), 480–484. https://doi.org/10.1016/j.wear.2010.05.003
[13] Jiang, L., Yahya, E., Ding, G., Hu, M., & Qin, S. (2013). The research of surface waviness control method for 5-axis flank milling. International Journal of Advanced Manufacturing Technology, 69, 835–847. https://doi.org/10.1007/s00170-013-5041-7
[14] Cai, C., Liang, X., An, Q., Tao, Z., Ming, W., & Ming Chen, M. (2021). Cooling/lubrication performance of dry and supercritical CO2-based minimum quantity lubrication in peripheral milling Ti-6Al-4V. International Journal of Precision Engineering and Manufacturing – Green Technology, 8(5), 405–421. https://doi.org/10.1007/s40684-020-00194-7
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[18] Yan, G., You, K., & Fang, F. (2020). Three-linear-axis grinding of small aperture aspheric surfaces. International Journal of Precision Engineering and Manufacturing – Green Technology, 7, 997–1008. https://doi.org/10.1007/s40684-019-00103-7
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[23] Pawlus, P., Reizer, R., Wieczorowski, M., & Krolczyk, G. (2020). Material ratio curve as information on the state of surface topography – A review. Precision Engineering, 65, 240-258. https://doi.org/ 10.1016/j.precisioneng.2020.05.008
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Autorzy i Afiliacje

Irina Beşliu-Băncescu
1
Laurenţiu Slătineanu
2
Margareta Coteaţă
2

  1. Stefan cel Mare University of Suceava, Department of Mechanics and Technology, Universitatii Street, 13, 720229 Suceava, Romania
  2. Gheorghe Asachi Technical University of Iasi, Department of Machine Manufacturing Technology, D. Mangeron Blvd, 59A, 700050 Iasi, Romania
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Abstrakt

Biogas, a renewable fuel, has low operational stability range in burners due to its inherent carbon-dioxide content. In cross-flow configuration, biogas is injected from a horizontal injector and air is supplied in an orthogonal direction to the fuel flow. To increase the stable operating regime, backward facing steps are used. Systematic numerical simulations of these flames are reported here. The comprehensive numerical model incorporates a chemical kinetic mechanism having 25 species and 121 elementary reactions, multicomponent diffusion, variable thermo-physical properties, and optically thin approximation based volumetric radiation model. The model is able to predict different stable flame types formed behind the step under different air and fuel flow rates, comparable to experimental predictions. Predicted flow, species, and temperature fields in the flames within the stable operating regime, revealing their anchoring positions relative to the rear face of the backward facing step, which are difficult to be measured experimentally, have been presented in detail. Resultant flow field behind a backward facing step under chemically reactive condition is compared against the flow fields under isothermal and non-reactive conditions to reveal the significant change the chemical reaction produces. Effects of step height and step location relative to the fuel injector are also presented.
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Bibliografia

[1] D. Andriani, A. Wresta, T.D. Atmaja, and A. Saepudin. A review on optimization production and upgrading biogas through CO 2 removal using various techniques. Applied Biochemistry and Biotechnology, 172(4):1909–1928, 2014. doi: 10.1007/s12010-013-0652-x.
[2] I.U. Khan, Mohd H.D. Othman, H. Hashim, T. Matsuura, A.F. Ismail, M. Rezaei-DashtArzhandi, and I. Wan Azelee. Biogas as a renewable energy fuel – A review of biogas upgrading utilization and storage. Energy Conversion and Management, 150:277–294, 2017. doi: 10.1016/j.enconman.2017.08.035.
[3] S. Rasi, A. Veijanen, and J. Rintala. Trace compounds of biogas from different biogas production plants. Energy, 32(8):1375–1380, 2007. doi: 10.1016/j.energy.2006.10.018.
[4] E. Ryckebosh, M. Drouillon, and H. Vervaeren. Techniques for transformation of biogas to biomethane. Biomass and Bioenergy, 35(5):1633–1645, 2011. doi: 10.1016/j.biombioe.2011.02.033.
[5] R.J. Spiegel, and J.L. Preston. Test results for fuel cell operation on anaerobic digester gas. Journal of Power Sources, 86(1-2):283–288, 2000. doi: 10.1016/S0378-7753(99)00461-9.
[6] H.-C. Shin, J.-W. Park, K. Park, and H.-C. Song. Removal characteristics of trace compounds of landfill gas by activated carbon adsorption. Environmental Pollution, 119(2):227–236, 2002. doi: 10.1016/s0269-7491(01)00331-1.
[7] R.J. Spiegel and J.L. Preston. Technical assessment of fuel cell operation on anaerobic digester gas at the Yonkers, NY, wastewater treatment plant. Waste Management, 23(8):709–717, 2003. doi: 10.1016/S0956-053X(02)00165-4.
[8] A. Lock, S.K. Aggarwal, I.K. Puri, and U. Hegde. Suppression of fuel and air stream diluted methane-air partially premixed flames in normal and microgravity. Fire Safety Journal, 43(1):24–35, 2008. doi: 10.1016/j.firesaf.2007.02.004.
[9] T. Leung and I. Wierzba. The effect of hydrogen addition on biogas non-premixed jet flame stability in a co-flowing air stream. International Journal of Hydrogen Energy, 33(14):3856–3862, 2008. doi: 10.1016/j.ijhydene.2008.04.030.
[10] A.M. Briones, S.K. Aggarwal, and V. Katta. A numerical investigation of flame liftoff, stabilization, and blowout. Physics of Fluids, 18(4):043603, 2006. doi: 10.1063/1.2191851.
[11] C.-E. Lee and C.-H. Hwang. An experimental study on the flame stability of LFG and LFG-mixed fuels. Fuel, 86(5-6):649–655, 2007. doi: 10.1016/j.fuel.2006.08.033.
[12] L. Xiang, H. Chu, F. Ren, and M. Gu. Numerical analysis of the effect of CO 2 on combustion characteristics of laminar premixed methane/air flames. Journal of the Energy Institute, 92(5):1487–1501, 2019. doi: 10.1016/j.joei.2018.06.018.
[13] N. Hinton and R. Stone. Laminar burning velocity measurements of methane and carbon dioxide mixtures (biogas) over wide ranging temperatures and pressures. Fuel, 116:743–750, 2014. doi: 10.1016/j.fuel.2013.08.069.
[14] S. Jahangirian, A. Engeda, and I.S. Wichman. Thermal and chemical structure of biogas counterflow diffusion flames. Energy and Fuels, 23(11):5312–5321, 2009. doi: 10.1021/ef9002044.
[15] A. Mameri and F. Tabet. Numerical investigation of counter-flow diffusion flame of biogas-hydrogen blends: Effects of biogas composition, hydrogen enrichment and scalar dissipation rate on flame structure and emissions. International Journal of Hydrogen Energy, 41(3):2011–2022, 2016. doi: 10.1016/j.ijhydene.2015.11.035.
[16] J.I. Erete, K.J. Hughes, L. Ma, M. Fairweather, M. Pourkashanian, and A. Williams. Effect of CO 2 dilution on the structure and emissions from turbulent, non-premixed methane-air jet flames. Journal of the Energy Institute, 90(2):191–200, 2017. doi: 10.1016/j.joei.2016.02.004.
[17] M.R.J. Charest, Ö.L. Gülder, and C.P.T. Groth. Numerical and experimental study of soot formation in laminar diffusion flames burning simulated biogas fuels at elevated pressures. Combustion and Flame, 161(10):2678–2691, 2014. doi: 10.1016/j.combustflame.2014.04.012.
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Autorzy i Afiliacje

Alagani Harish
1
ORCID: ORCID
Vasudevan Raghavan
1

  1. Indian Institute of Technology Madras, Chennai, India

Abstrakt

Influenced by the dynamic pressure of the front abutment pressure and the lateral abutment pressure, large deformation of surrounding rock occurs advancing working face in the entry heading adjacent to the active longwall mining face. Based on the cause analysis of entry large deformation, a new technology was put forward to solve the problem, and the designing method of drilling hole parameters for directional hydraulic fracturing was formed. Holes are drilled in the entry or in the high drainage entry to a certain rock layer over the adjacent working face, hydraulic cutting or slotting at the bottom of a borehole were also applied in advance to guide the hydraulic fractures extend in expected direction, through which the hard roof above the coal pillar can be cut off directionally. As a result, the stress concentration around the entry was transferred, and the entry was located in a destressing area. The field test at Majialiang coal mine indicates that the propagation length of cracks in single borehole is more than 15 m. After hydraulic fracturing, the large deformation range of the entry is reduced by 45 m, the average floor heave is reduced by 70%, and the average convergence of the entry’s two sides is reduced by 65%. Directional hydraulic fracturing has a better performance to control the large deformation of the dynamic pressure of the entry heading adjacent to the advancing coal face. Besides, it can improve the performance of the safety production.

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Autorzy i Afiliacje

Bingxiang Huang
Xinglong Zhao
Jian Ma
ORCID: ORCID
Tianyuan Sun

Abstrakt

The 13th-century Persian poet Saʿdi from Shiraz is considered to be one of the most prominent representatives of medieval Persian ethical literature. His works full of moralizing anecdotes were well known and widely read not only in Persia, but in the other parts of the Islamic world as well. Due to his highly humanistic approach, the relations between people were one of the most important issues discussed by the poet. This article is an attempt to define the status of ‘speech’ in Saʿdi’s moral imagination and to show how it becomes a key instrument in shaping relations with others. In the poet’s opinion, the right words reasonably spoken, just like an appropriate silence, shape the relationship between people and help them avoid conflict and open dispute. Quarrels and confrontations, according to the poet, not only damage a person literally by exposing his flaws and imperfections of character, thereby compromising his reputation (aberu), but may also undermine the basis of social life, generating hostility between people. That is why Saʿdi urges his readers to use soft and gentle speech in dealing with people and always behave in a conciliatory manner in response to aggression and rudeness. Highlighting the moral aspect of speech, Saʿdi shows how kind words form an invisible veil between people, which should be preserved if man desires to maintain his image, good name and dignity.

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Autorzy i Afiliacje

Magdalena Rodziewicz
ORCID: ORCID

Abstrakt

The deformation and failure law of stope roofs is more complicated than horizontal coal seams affected by the angle of the coal seam during the mining process of steeply dipping coal seams. This study focused on and analysed the working face of a 2130 coal mine with steep dipping and large mining height. Through the use of numerical calculation, theoretical analysis, physical similar material simulation experiments, and field monitoring, the distribution characteristics of roof stress, as well as the threedimensional caving migration and filling law, in large mining height working faces under the dip angle effect was investigated. The influence mechanism of the dip angle change on the roof stability of large mining heights was investigated. The results revealed that the roof stress was asymmetrically distributed along the inclination under the action of the dip angle, which resulted in roof deformation asymmetry. With the increase in the dip angle, the rolling and sliding characteristics of roof-broken rock blocks were more obvious. The length of the gangue support area increased, the unbalanced constraint effect of the filling gangue on the roof along the dip and strike was enhanced, and the height of the caving zone decreased. The stability of the roof in the lower inclined area of the working face was enhanced, the failure range of the roof migrated upward, and the damage degree of the roof in the middle and upper areas increased. Furthermore, cross-layer, large-scale, and asymmetric spatial ladder rock structures formed easily. The broken main roof formed an anti-dip pile structure, and sliding and deformation instability occurred, which resulted in impact pressure. This phenomenon resulted in the dumping and sliding of the support. The ‘support-surrounding rock’ system was prone to dynamic instability and caused disasters in the surrounding rock. The field measurement results verified the report and provided critical theoretical support for field engineering in practice.
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Autorzy i Afiliacje

Panshi Xie
1 2
Baofa Huang
1 2
Yongping Wu
1 2
ORCID: ORCID
Shenghu Luo
2 3
ORCID: ORCID
Tong Wang
1 2
ORCID: ORCID
Zhuangzhuang Yan
1 2
Jianjie Chen
4

  1. Xi’an University of Science and Technology, School of Energy Engineering, Xi’an 710054, China
  2. Xi’an University of Science and Technology, Key Laboratory of Western Mine Exploitation and Hazard Prevention Ministry of Educat ion, Xi’an 710054, China
  3. Xi’an University of Science and Technology, Department of Mechanics, Xi’an, 710054, China
  4. Xinjiang Coking Coal Group Corporat ion Limited, Xinjiang 830025, China
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Abstrakt

This work is an experimental study of thermo-mechanical surface hardening of mild steel with trace elements like titanium in negligible concentrations. This is somewhat an advanced technique used to harden steel surface which can be hardened in many typical ways. The concept is combining the thermal as well as mechanical technique to attain better results. It is quite obvious that mechanical refers to the compressive loading during machining and thermal refers to producing heat on the surface of work piece. The ideal conditions are when the heat produced is enough to achieve austenite and then subsequent quick cooling helps in the formation of martensite, which is metallurgically the most highly strong phase of steel, in terms of hardness. The coolant used preferably is the emulsified oil which flows on the surface during machining with variable rate of flow as the optimum effect is. This process hardens the surface of steel and increases its resistance against wear and abrasion. Preference is to achieve surface hardening using the conventional equipment so that operational cost is kept low and better results are attained. This technique has been quite successful in the laboratory. It can be termed as friction hardening. Some improvements in the process scheme and working environment can be made to get better results.
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Bibliografia

[1] Muñoz, J.A., Avalos, M., Schell, N., Brokmeier, H.G. & Bolmaro, R.E. (2021). Comparison of a low carbon steel processed by Cold Rolling ( CR ) and Asymmetrical Rolling (ASR): Heterogeneity in strain path, texture, microstructure and mechanical properties. Journal of Manufacturing Processes. 64(February), 557-575. DOI: 10.1016/J.JMAPRO.2021.02.017.
[2] Hotz, H. & Kirsch, B. (2020). Influence of tool properties on thermomechanical load and surface morphology when cryogenically turning metastable austenitic steel AISI 347. Journal of Manufacturing Processes. 52(August 2020), 120-31. https://doi.org/10.1016/j.jmapro.2020.01.043.
[3] Burke, J.J., Weiss, V. (1974). Advances in deformation processing. New York: Plenum Press.
[4] Bernardo, L., Tressia, G., Masoumi, M., Mundim, E., Regattieri, C. & Sinatora, A. (2021). Roller crushers in iron mining, how does the degradation of Hadfield steel components occur ? Engineering Failure Analysis. 122(February), 105295, 1-18. DOI: 10.1016/j.engfailanal. 2021.105295.
[5] Fedorova, L.V., Fedorov, S.K., Serzhant, A.A., Golovin, V.V. & Systerov, S.V. (2017). Electromechanical surface hardening of tubing steels. Metal Science and Heat Treatment. 59(3-4), 173-175. DOI: 10.1007/s11041-017-0123-z.
[6] Vafaeian, S., Fattah-Alhosseini, A., Mazaheri, Y. & Keshavarz, M.K. (2016). On the study of tensile and strain hardening behavior of a thermomechanically treated ferritic stainless steel. Materials Science and Engineering A. 669, 480-489. http://dx.doi.org/10.1016/j.msea.2016.04.050.
[7] Shi, F., Yin, S., Pham, T.M., Tuladhar, R. & Hao, H. (2021). Pullout and flexural performance of silane groups and hydrophilic groups grafted polypropylene fibre reinforced UHPC. Construction and Building Materials. 277, 122335, 1-10. https://doi.org/10.1016/j.conbuildmat.2021.122335.
[8] Gao, J., Yu, M., Liao, D., Zhu, S., Zhu, Z. & Han, J. (2021). Foreign object damage tolerance and fatigue analysis of induction hardened S38C axles. Materials & Design. 202, 109488, 1-10. https://doi.org/10.1016/j.matdes.2021.109488.
[9] Bedford, G.M., Vitanov, V.I. & Voutchkov, I.I. (2001). On the thermo-mechanical events during friction surfacing of high speed steels. Surface and Coatings Technology. 141, 34-39. https://doi.org/10.1016/S0257-8972(01)01129-X.
[10] Ahmed, W., Hegab, H., Mohany, A. & Kishawy, H. (2021). On machining hardened steel AISI 4140 with self-propelled rotary tools : experimental investigation and analysis. The International Journal of Advanced Manufacturing Technology. 11-12, 113, 3163–3176.
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Autorzy i Afiliacje

Ali R. Sheikh
1
ORCID: ORCID

  1. AGH University of Science and Technology, Poland

Abstrakt

The roof-caving step scale goaf behind the working face is sensitive to the region’s spontaneous combustion and gas concentration distribution, including many rock block cracks and holes. A severe deviation from the dynamics of fluids in porous media by representative element volume (REV), leading to the results of Computational Fluid Dynamics (CFD) simulation, has a significant error. A heterogeneous two-dimensional pore network model was established to simulate the goaf flow accurately. The network was first created using the simple cubic lattice in the OpenPNM package, and the spatial distribution of the “O-ring” bulking factor was mapped to the network. The bulking factor and Weibull distribution were combined to produce the size distribution of the pore and throat in the network. The constructed pore network model was performed with single-phase flow simulations. The study determined the pore structure parameters of the pore network through the goaf’s risked falling characteristics and described the flow field’s distribution characteristics in the goaf. The permeability coefficient increases as pore diameter, throat diameter, pore volume and throat volume increase and increases as throat length decreases. The correlation between throat volume and permeability coefficient is the highest, which indicates that the whole throat is the main control factor governing the air transport capacity in the goaf. These results may provide some guidelines for controlling thermodynamic disasters in the goaf.
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Autorzy i Afiliacje

Ke Gao
1
ORCID: ORCID
Qiwen Li
1
ORCID: ORCID
Lianzeng Shi
1
ORCID: ORCID
Aobo Yang
1
ORCID: ORCID
Zhipeng Qi
1
ORCID: ORCID

  1. Liaoning Technical University, College of Safety Science and Engineering, Key Laboratory of Mine Thermodynamic Disasters and Control Of Ministry Of Education, China

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