Comparison of the Methods for Calculating Instant Depth of Cut

2013 ◽  
Vol 634-638 ◽  
pp. 3313-3320 ◽  
Author(s):  
Yong Sun ◽  
X.S. Li
Keyword(s):  
Theoretical Analysis ◽  
Calculation Method ◽  
Approximate Formula ◽  
Accurate Solution ◽  
Mining Machine ◽  
Depth Of Cut ◽  
Calculation Methods ◽  
Continuous Mining ◽  
Selection Of ◽  
Advance Speed

When cutting rocks using mechanical excavators, the depth of cut (DOC) of cutting picks is a major factor that affects the forces on the picks and the drum on which the picks are installed. To optimize the design of the picks and the drum, as well as the operation of the continuous mining machine, it is necessary to analyze the DOC of individual picks accurately. In a cutting cycle, different picks can be in various positions and consequently have diverse DOCs which are termed the instant DOCs at the corresponding positions. In this study, it is aimed to investigate both accurate solution and approximate formula for the calculation of instant DOC. Based on theoretical analysis, the equations for the calculation of instant DOC have been developed, and the quantitative comparisons between the different DOC calculation methods have been made. The influence of the advance speed per revolution of the drum on the instant DOC, the cut interactions between picks and the cutting sections of individual picks have also been investigated. The results can assist in the selection of an appropriate DOC calculation method and improvement of drum design and operation.

Influence of Cutting Parameters and Interactions on the Depth of Cut in Continuous Mining Operation

2012 ◽  
Vol 538-541 ◽  
pp. 1422-1428 ◽  
Author(s):  
Yong Sun ◽  
X S Li ◽  
Wen Shao
Keyword(s):  
Mining Operation ◽  
Cutting Parameters ◽  
Mining Machine ◽  
Depth Of Cut ◽  
Force Analysis ◽  
Accurate Analysis ◽  
Cutting Line ◽  
Continuous Mining ◽  
Advance Speed

During mechanized continuous mining, the depth of cut (DOC) of picks on the drum directly affects the forces exerted on the picks, as well as the forces and torque acting on the drum. Therefore, accurate analysis of DOC of individual picks is needed to optimize the design of the drum and the operation of the continuous mining machine. However, the current existing models cannot meet this need, because they only take into account drum advance speed per revolution and the spirals of picks or the picks per cutting line. In this paper, we attempt to improve the accuracy of DOC calculation by considering drum advance speed per revolution, cutting patterns, the interactions between picks and the profiles of picks. Furthermore, the change of DOC of individual pick in a cutting cycle is also analyzed. The proposed models can help calculate pick forces and drum’s reactive forces more accurately. They also enable those empirical force models which are developed based on the experiments with small DOC to be used for force analysis with larger DOC more accurately.

The Research Project «Names of Modern Professions» in Extracurricular Work with 6-th Grade Russian Students

2020 ◽  
Vol 81 (6) ◽  
pp. 23-31
Author(s):  
M. I. Vasileva
Keyword(s):  
Theoretical Analysis ◽  
Scientific Literature ◽  
Research Process ◽  
Russian Language ◽  
Research Project ◽  
Educational Activities ◽  
Research Activities ◽  
The Russian Language ◽  
Selection Of

The aim of the study was to investigate approaches to the formation of general educational skills. A survey examining the design and research process was carried out by 6th-grade Russian students over the course of an extracurricular project entitled «Names of Modern Professions». In the paper, the selection of the «Lexicology» section for such activities carried out by school pupils is substantiated and stages of work on the project are described. The applied methodology involves theoretical analysis of scientific literature, formative experimentation, analysis of products of educational activities, observation and description. It is concluded that the design of extracurricular research activities in the Russian language contributes to the formation of general educational competencies in conducting surveys and searching for information on the basis of subject skills.

Effect of Operator Position on the Incidence of Continuous Mining Machine/Worker Collisions

2007 ◽  
Vol 51 (20) ◽  
pp. 1416-1420
Author(s):  
John R. Bartels ◽  
Dean H. Ambrose ◽  
Sean Gallagher
Keyword(s):  
Response Times ◽  
Health And Safety ◽  
Mining Machine ◽  
Workplace Relationships ◽  
Continuous Miner ◽  
Work Posture ◽  
Close Proximity ◽  
Continuous Mining ◽  
Machine Speed ◽  
Machine Work

Remote operation of continuous miners has enhanced the health and safety of underground miners in many respects; however, numerous fatal and non-fatal continuous miner struck-by accidents have occurred when using remote controls. In an effort to prevent these injuries, NIOSH researchers at Pittsburgh Research Laboratory examined the workplace relationships between continuous miner operators and various tramming modes of the equipment using motion captured data, predicted operator response times, and field- of- view data to determine causes of operator-machine struck-by events in a virtual mine environment. Factors studied included machine speed, direction of escape, operator facing orientation relative to the machine, work posture, distance from machine, and operator anthropometry. Close proximity to the machine, high machine tramming speeds, a right-facing orientation and operator positioning near the tail all resulted in high risk of being struck. It is hoped that this data will provide an improved rationale for operator positioning for remotely operated continuous miners.

New Development in High Efficiency Deep Grinding

2012 ◽  
Author(s):  
Andre D. L. Batako ◽  
Valery V. Kuzin ◽  
Brian Rowe
Keyword(s):  
Machine Tool ◽  
High Efficiency ◽  
Machining Process ◽  
Depth Of Cut ◽  
Removal Rates ◽  
Workpiece Surface ◽  
New Development ◽  
Cutting Processes ◽  
Selection Of ◽  
Made In

High Efficiency Deep Grinding (HEDG) has been known to secure high removal rates in grinding processes at high wheel speed, relatively large depth of cut and moderately high work speed. High removal rates in HEDG are associated with very efficient grinding and secure very low specific energy comparable to conventional cutting processes. Though there exist HEDG-enabled machine tools, the wide spread of HEDG has been very limited due to the requirement for the machine tool and process design to ensure workpiece surface integrity. HEDG is an aggressive machining process that requires an adequate selection of grinding parameters in order to be successful within a given machine tool and workpiece configuration. This paper presents progress made in the development of a specialised HEDG machine. Results of HEDG processes obtained from the designed machine tool are presented to illustrate achievable high specific removal rates. Specific grinding energies are shown alongside with measured contact arc temperatures. An enhanced single-pole thermocouple technique was used to measure the actual contact temperatures in deep cutting. The performance of conventional wheels is depicted together with the performance of a CBN wheel obtained from actual industrial tests.

Application of MCDM-based TOPSIS method for the selection of optimal process parameter in turning of pure titanium

2017 ◽  
Vol 24 (7) ◽  
pp. 2009-2021 ◽  
Author(s):  
Akhtar Khan ◽  
Kalipada Maity
Keyword(s):  
Decision Making ◽  
Cutting Force ◽  
Pure Titanium ◽  
Cutting Speed ◽  
Optimal Combination ◽  
Depth Of Cut ◽  
Topsis Method ◽  
Content Type ◽  
Cp Ti ◽  
Selection Of

Purpose The purpose of this paper is to explore a multi-criteria decision-making (MCDM) methodology to determine an optimal combination of process parameters that is capable of generating favorable dimensional accuracy and product quality during turning of commercially pure titanium (CP-Ti) grade 2. Design/methodology/approach The present paper recommends an optimal combination of cutting parameters with an aim to minimize the cutting force (Fc), surface roughness (Ra), machining temperature (Tm) and to maximize the material removal rate (MRR) after turning of CP-Ti grade 2. This was achieved by the simultaneous optimization of the aforesaid output characteristics (i.e. Fc, Ra, Tm, and MRR) using the MCDM-based TOPSIS method. Taguchi’s L9 orthogonal array was used for conducting the experiments. The output responses (cutting force: Fc, surface roughness: Ra, machining temperature: Tm and MRR) were integrated together and presented in terms of a single signal-to-noise ratio using the Taguchi method. Findings The results of the proposed methodology depict that the higher MRR with desirable surface quality and the lower cutting force and machining temperature were observed at a combination of cutting variables as follows: cutting speed of 105 m/min, feed rate of 0.12 mm/rev and depth of cut of 0.5 mm. The analysis of variance test was conducted to evaluate the significance level of process parameters. It is evident from the aforesaid test that the depth of cut was the most significant process parameter followed by cutting speed. Originality/value The selection of an optimal parametric combination during the machining operation is becoming more challenging as the decision maker has to consider a set of distinct quality characteristics simultaneously. This situation necessitates an efficient decision-making technique to be used during the machining operation. From the past literature, it is noticed that only a few works were reported on the multi-objective optimization of turning parameters using the TOPSIS method so far. Thus, the proposed methodology can help the decision maker and researchers to optimize the multi-objective turning problems effectively in combination with a desirable accuracy.

Influences of Mining Depths of Coal Faces in Duanwang Coal Mine on the Gas Emission Law

2013 ◽  
Vol 295-298 ◽  
pp. 2874-2878
Author(s):  
Xin Xian Zhai ◽  
Yan Wei Zhai ◽  
Shi Wei Zhang
Keyword(s):  
Theoretical Analysis ◽  
Coal Mine ◽  
Production Capacity ◽  
Control Measures ◽  
Shanxi Province ◽  
Coal Face ◽  
Gas Emission ◽  
Average Value ◽  
Mining Depth ◽  
Selection Of

Duanwang Coal Mine in Shanxi province, China, is located at north of Qinshui coalfield which gently inclined and thick seams have been mined. Authorized production capacity of the coal mine is 1.8Mt/a. With the increase of mining depth, the mine gas emission quantity increased. The mine became high gassy one from low gassy mine. Using field measurement and theoretical analysis methods, the following conclusion can be drawn. Gas emission quantity of coal face is directly correlated with mining depth. With the increase of mining depth, both absolute and relative gas emission quantities at coal face increased. The gradient of gas emission quantity was 0.0438-0.1338m3/t/m, the average value was 0.1062m3/t/m. These results would provide a foundation for prediction of the gas emission quantity and selection of gas control measures.

scholarly journals Developing Soft Skills among Potential Employees: A Theoretical Review on Best International Practices

2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Oleksandr Malykhin ◽  
Nataliia Oleksandrivna Aristova ◽  
Liudmyla Kalinina ◽  
Tetyana Opaliuk
Keyword(s):  
Professional Development ◽  
Theoretical Analysis ◽  
Soft Skills ◽  
The Other ◽  
Skills Development ◽  
Common Language ◽  
The Common ◽  
The One ◽  
A Company ◽  
Selection Of

The present paper addresses the issue of determining the best international practices for developing soft skills among students of different specialties through carrying out a theoretical review. Basing on literature on present-day theory the authors make an attempt to explain soft skills dichotomies, summarize existing approaches to classifying soft skills, consolidate and document best international practices for soft skills development among potential employees of different specialties including bachelor students, master students, doctoral and postdoctoral students. The data obtained in the theoretical analysis reveal that the possible ambiguities in the interpretation of the concept of “soft skills” are caused, on the one hand, by the dichotomic perception of their nature by present-day researchers and educators and, on the other hand, by the absence of the common language which makes it difficult to provide a more unified definition most satisfactory to all concerned. The authors are convinced that soft skills have a cross-cutting nature and regard them as personal and interpersonal meta-qualities and meta-abilities that are vital to any potential employee who is going to make positive contributions not only to his/her professional development but to the development of a company he/she is going to work for. The results of the conducted theoretical review clearly indicate that the absence of the unified understanding of the concept of “soft skills” is reflected in the existence of different approaches to classifying soft skills, let alone, the selection of didactic tools for developing soft skills among potential employees.

Sign in / Sign up

Export Citation Format

Share Document