Recent Patents on Roll Crushing Mills for Selective Crushing of Coal and Gangue

2020 ◽  
Vol 13 (1) ◽  
pp. 2-12 ◽  
Author(s):  
Daolong Yang ◽  
Yanxiang Wang ◽  
Bangsheng Xing ◽  
Yanting Yu ◽  
Yuntao Wang ◽  
...  
Keyword(s):  
Traditional Approach ◽  
Ground Level ◽  
Electric Machine ◽  
Coal Gangue ◽  
Land Occupation ◽  
Transmission Problems ◽  
Environmental Treatment ◽  
Transport Volume ◽  
Complex Transmission ◽  
Roll Crusher

Background: Gangue is the concomitant product of coal mining. The traditional approach for gangue treatment is to transport it from underground to ground level to accumulate and form gangue hills. Objective: On the basis of summarizing previous research results, this paper introduces the hydraulic roller crusher and the electric machine built-in coal gangue roller crusher, which avoids the complex transmission problems caused by the movement of the central axis when the roller crusher is allowed to roll. Methods: The hydraulic counter-roll crusher directly separates large pieces of coal and underground gangue such that large pieces of coal gangue do not escape from the well. The electric machine built-in roller crusher is an explosion-proof electric machine used in the crushing roller. Results: Both of these crushers can be used in the selective crushing technology of coal gangue in a coal mine and can meet the requirements of crushing different material sizes and generally avoid the centre of the roller crusher. Conclusion: Both of these crushers reduce transportation costs, minimise land occupation, prevent surface subsidence, decrease environmental treatment costs, reduce environmental pollution, and decrease the transport volume of gangue underground. Various patents have been discussed in this article.

A New Comprehensive Utilization Method for Coal Gangue: Preparing Alite-Sulphoaluminate Cement

2013 ◽  
Vol 652-654 ◽  
pp. 1527-1532 ◽  
Author(s):  
Guan Li Xu ◽  
Chuan Min Sun ◽  
Yao Sun ◽  
Hai Liao
Keyword(s):  
Compressive Strength ◽  
Water Treatment ◽  
Solid Waste ◽  
Coal Industry ◽  
Coal Gangue ◽  
High Alumina ◽  
Land Occupation ◽  
Comprehensive Utilization ◽  
Sulphoaluminate Cement ◽  
High Alumina Content

Coal gangue is a kind of solid waste which is discharged from coal mining and coal washing. Dumped gangues do not only take a large land occupation but also pollute air and water. Treatment and utilizing of coal gangues has become the major issue for the coal industry to resolve. As major experimental material in this study, the coal gangue from Dawukou, Shizuishan, Ningxia province, China had been analyzed to have high-alumina content, and it could been used as alumina constituent for the preparation of sulphoaluminate cement. In this paper, alite-sulphoaluminate cements were prepared at 1330°C using coal gangue, limestone and gypsum as major main materials, fluorite and barite as minor materials. The result shows that major clinker minerals of the cement are sulphoaluminate, alite and belite, while major hydrate is ettringite, compressive strength of the cement is 48.9MPa after 7d. These experiments provide a new method of coal gangue comprehensive utilization.

scholarly journals 3D propagation of relativistic solar protons through interplanetary space

2020 ◽  
Vol 639 ◽  
pp. A105
Author(s):  
S. Dalla ◽  
G. A. de Nolfo ◽  
A. Bruno ◽  
J. Giacalone ◽  
T. Laitinen ◽  
...  
Keyword(s):  
Interplanetary Space ◽  
Traditional Approach ◽  
Ground Level ◽  
Mean Free Path ◽  
Heliospheric Current Sheet ◽  
High Spectral Resolution ◽  
Particle Model ◽  
3D Effects ◽  
Field Lines ◽  
Energy Dependent

Context. Solar energetic particles (SEPs) with energy in the GeV range can propagate to Earth from their acceleration region near the Sun and produce ground level enhancements (GLEs). The traditional approach to interpreting and modelling GLE observations assumes particle propagation which is only parallel to the magnetic field lines of interplanetary space, that is, spatially 1D propagation. Recent measurements by PAMELA have characterised SEP properties at 1 AU for the ∼100 MeV–1 GeV range at high spectral resolution. Aims. We model the transport of GLE-energy solar protons using a 3D approach to assess the effect of the heliospheric current sheet (HCS) and drifts associated to the gradient and curvature of the Parker spiral. We derive 1 AU observables and compare the simulation results with data from PAMELA. Methods. We use a 3D test particle model including a HCS. Monoenergetic populations are studied first to obtain a qualitative picture of propagation patterns and numbers of crossings of the 1 AU sphere. Simulations for power law injection are used to derive intensity profiles and fluence spectra at 1 AU. A simulation for a specific event, GLE 71, is used for comparison purposes with PAMELA data. Results. Spatial patterns of 1 AU crossings and the average number of crossings per particle are strongly influenced by 3D effects, with significant differences between periods of A+ and A− polarities. The decay time constant of 1 AU intensity profiles varies depending on the position of the observer and it is not a simple function of the mean free path as in 1D models. Energy dependent leakage from the injection flux tube is particularly important for GLE energy particles, resulting in a rollover in the spectrum.

scholarly journals FISHEYE PHOTOGRAMMETRY TO GENERATE LOW-COST DTMS

2019 ◽  
Vol XLII-2/W17 ◽  
pp. 257-263
Author(s):  
L. Perfetti ◽  
F. Fassi ◽  
C. Rossi
Keyword(s):  
Spatial Information ◽  
Traditional Approach ◽  
Low Cost ◽  
Digital Camera ◽  
Ground Level ◽  
Archaeological Site ◽  
Wide Angle Lens ◽  
Low Altitude ◽  
Archaeological Areas ◽  
Image Network

Abstract. In the archaeological practice, Digital Terrain Models (DTMs) and Digital Surface Models (DSMs) may be used to represent spatial information about the site by conveying information such as differences in levels, morphology of the terrain and movements of volumes during the excavation. Nowadays DTMs and DSMs can be easily obtained by image-based matching using low altitude aerial dataset acquired from a digital camera by means of a lifting device. In recent years, the spread of commercial multi-rotor unmanned aerial vehicles and their decreasing cost made low-altitude aerial photography even easier than before, where balloons, kites and telescopic masts would have been used instead. However, the use of drones is often forbidden by law, especially in the archaeological areas, and therefore a more traditional approach must to be adopted instead.This paper presents two different approaches adopted on the field to acquire the DTM of an archaeological excavation: the use of a pole held by a chest harness to lift a camera up to 3.5 m height fitted with a 20 mm wide angle lens; and a second solution that exploits ground-based fisheye photogrammetry. In general, an image network acquired from ground level is challenging due to: i) the poor coverage that can be obtained on the ground, ii) the large number of images that are required to cover large areas and consequently iii) the longer elaboration time that is required to process the data. The fisheye approach, however, proved to be more effective thanks to the more robust image network resulting both from the wider field of view and from the possibility to handle large datasets by downsampling the images and still retrieving strong key points. The main difference with the first system is that the monotonous images acquired by the 20 mm lens, very plain in texture, require working at full resolution in order to distinguish valid features in the sand.The final product of the tests carried out along this line in 2019 at Saqqara (Egypt) is a comprehensive DSM of the entire archaeological site with an accuracy of ~3 cm.

Electric Machine Undergraduate Lab: A Traditional Approach with a New Technical Base

2007 ◽  
Vol 44 (1) ◽  
pp. 12-22 ◽  
Author(s):  
A. J. Conejo ◽  
J. M. Arroyo ◽  
F. Milano ◽  
J. A. Mora
Keyword(s):  
Traditional Approach ◽  
Electric Machine ◽  
Technical Base

Effects of Vibration on the Preparation of Ultrathin Sections

1973 ◽  
Vol 31 ◽  
pp. 358-359
Author(s):  
Joseph M. Blum ◽  
Edward P. Gargiulo ◽  
J. R. Sawers
Keyword(s):  
Cutting Speed ◽  
Ground Level ◽  
Environmental Vibration ◽  
Block Face ◽  
Ultrathin Sections ◽  
Embedding Medium ◽  
Thickness Variations ◽  
Building Walls ◽  
Cutting Direction ◽  
Diamond Knife

It is now well-known that chatter (Figure 1) is caused by vibration between the microtome arm and the diamond knife. It is usually observed as a cyclical variation in “optical” density of an electron micrograph due to sample thickness variations perpendicular to the cutting direction. This vibration might be induced by using too large a block face, too large a clearance angle, excessive cutting speed, non-uniform embedding medium or microtome vibration. Another prominent cause is environmental vibration caused by inadequate building construction. Microtomes should be installed on firm, solid floors. The best floors are thick, ground-level concrete pads poured over a sand bed and isolated from the building walls. Even when these precautions are followed, we recommend an additional isolation pad placed on the top of a sturdy table.

A global perspective of ground level, 'ambient' carbon dioxide for assessing the response of plants to atmospheric CO2

2001 ◽  
Vol 7 (7) ◽  
pp. 789-796 ◽  
Author(s):  
L. H. Ziska ◽  
O. Ghannoum ◽  
J. T. Baker ◽  
J. Conroy ◽  
J. A. Bunce ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Ground Level ◽  
Global Perspective ◽  
Atmospheric Co2

Perceptions of a Peer Suicide Prevention Program by Inmates and Professionals Working in Prisons

Crisis ◽  
2013 ◽  
Vol 34 (4) ◽  
pp. 289-292 ◽  
Author(s):  
Laurent Auzoult ◽  
Sid Abdellaoui
Keyword(s):  
Suicide Prevention ◽  
Prevention Program ◽  
Suicide Risk ◽  
Traditional Approach ◽  
Prevention Programs ◽  
New Methods ◽  
Penal Institutions ◽  
Peer Suicide ◽  
Suicide Prevention Programs ◽  
Methods Of Suicide

Background: Suicide prevention is a major challenge for penal institutions in many countries. The traditional approach relies on the expertise of health professionals and is supplemented by the intervention of other professionals and the inmates themselves. New methods of suicide prevention based on peer support have been developed in recent years. Peer prevention programs rely on the ability of inmates to identify suicide risk. Aims: This study examines perceived suicide risk among inmates and explores possible explanations. Method: 54 inmates and 17 professionals working in prisons responded to a questionnaire. Results: The peer prevention program was found to change inmates’ expectations of support in the event of a suicide crisis. The study also found that the inmates involved in the program tended to underestimate the risk of suicide. The perception of the prevention program and the level of self-consciousness were found to account for the underestimation of suicide risk. Conclusions: Support for inmates involved in suicide prevention programs must take into account their isolation in prison. The training provided to inmates must also consider the biases affecting the assessment of risk.

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