scholarly journals Study on the strength property and ratio parameter selection of waste rock cemented backfill

2021 ◽  
Vol 2 (1) ◽  
pp. 7-13
Author(s):  
Xiaoming Wei ◽  
Lijie Guo ◽  
Lei Zhang
Keyword(s):  
Flow Property ◽  
Waste Rock ◽  
Parameter Determination ◽  
Slurry Concentration ◽  
Strength Change ◽  
Cemented Backfill ◽  
Unclassified Tailings ◽  
Research Findings ◽  
Slurry Stability

When tailings are used for cemented backfill preparation, the extremely fine unclassified tailings may lead to slow consolidation and low strength of backfill material. Wasted rock as an additional filling aggregated was suggested to optimize the gradation composition of aggregate by scholars over the world. In this paper, the effect of waste rock addition, cement-tailing ratio and slurry concentration on strength and flow properties of waste rock cemented backfill were studied. The results indicate the strength of waste rock cemented backfill was significantly higher than that of unclassified tailings cemented backfill under same cement consumption, which the average strength improvements were 2.02MPa, 0.98MPa and 0.46MPa under cement-tailing ratio of 1:4, 1:8 and 1:10. With the increase of waste rock addition, the strength change of waste rock cemented backfill was less obvious, but the flow property (yield stress) of filling slurry was improved. Further analysis of the slurry stability illustrates that, with the increase of waste rock addition, the bleeding rate demonstrated a trend similar to that observed for the flow property, however, in an adverse manner. Overall, the optimal slurry concentration of 80% and waste rock addition of 40%～50% were determined. Based on the strength requirement, cement dosage was selected, which the cement-tailing ratio of top 10m and the bottom 10m was 1:8, the cement-tailing ratio of the centre stope was 1:10. The research findings can provide a reference for the ratio parameter determination of extremely fine unclassified tailings backfill of similar mines.

High Strength Combined Support Technology in Deep High Stress Soft Rock Roadway

2012 ◽  
Vol 524-527 ◽  
pp. 598-603
Author(s):  
Nian Jie Ma ◽  
Zhi Qiang Zhao ◽  
Hua Zhao ◽  
Li Shuai Jiang
Keyword(s):  
High Stress ◽  
Soft Rock ◽  
High Strength ◽  
Parameter Determination ◽  
Test Results ◽  
Actual Measurement ◽  
Computer Numerical Simulation ◽  
Soft Rock Roadway ◽  
Rock Roadway

In order to solve the serious damage and repeat revision problem of high stress soft rock roadway in deep -950 level of Tangshan coal mine, based on the theory of the maximum stress level, together with the actual measurement of geostress and the laboratory mechanical parameters of rock-core and computer numerical simulation, the high strength combined support technology and supporting parameters are determined and the engineering test has been done. The engineering test results show that the parameter determination of high strength combined support technology, which based on the actual measurement of geostress, can effective solve the support issue of high stress soft rock roadway and provide useful experience for similar engineering problems.

A Novel and Fundamental Approach Toward Field and Damper Circuit Parameter Determination of Synchronous Machine

2013 ◽  
Vol 49 (5) ◽  
pp. 2097-2105 ◽  
Author(s):  
Kaushik Mukherjee ◽  
K. Lakshmi Varaha Iyer ◽  
Xiaomin Lu ◽  
Narayan C. Kar
Keyword(s):  
Synchronous Machine ◽  
Parameter Determination ◽  
Circuit Parameter

Problem of angular motion control of a non-cooperative on-orbit service object

2021 ◽  
Vol 2021 (1) ◽  
pp. 37-50
Author(s):  
A.A. Fokov ◽  
◽  
O.P. Savchuk ◽  
Keyword(s):  
Motion Control ◽  
State Of The Art ◽  
Object Motion ◽  
The State ◽  
Angular Motion ◽  
Motion Parameter ◽  
Rotary Motion ◽  
Parameter Determination ◽  
Service Object

The realization of existing projects of on-orbit servicing and the development of new ones is a steady trend in the development of space technology. In many cases, on-orbit service clients are objects that exhibit an undesired rotary motion, which renders their servicing difficult or impossible. The problem of on-orbit service object motion control determines the topicality of studies aimed not only at the refinement of methods and algorithms of controlling both the translational and the rotary motion of an object, but also at the development and refinement of methods of onboard determination of the object – service spacecraft relative motion parameters. This paper overviews the state of the art of the problem of object motion parameter determination in on-orbit servicing tasks and existing methods of object motion control and angular motion damping and specifies lines of further investigations into the angular motion control of non-cooperative service objects. Based on the analysis of publications on the subject, the applicability of onboard means for object motion parameter determination is characterized. The analysis of the applicability of methods of remote determination of the parameters of an unknown non-cooperative object from a service spacecraft shows that they are at the research stage. The input data for the verification of methods proposed in the literature were simulated or taken from ground experiments or previous missions. Contact and contactless methods of angular motion control of non-cooperative on-orbit service objects are considered. From the state of the art of investigations into the contactless motion control of on-orbit service objects it may be concluded that the most advanced contactless method of motion control of an on-orbit service object is a technology based on the use of an ion beam directed to the object from an electrojet engine onboard a service spacecraft. Lines of further investigations into non-cooperative object motion control are proposed.

scholarly journals Understanding Uncertainty and Risk in Management

2020 ◽  
Vol 12 (1) ◽  
pp. 12-35
Author(s):  
Piotr Jedynak ◽  
Sylwia Bąk
Keyword(s):  
Value Added ◽  
Research Process ◽  
Main Method ◽  
Proper Understanding ◽  
Organization Management ◽  
One Dimensional ◽  
Modern Management ◽  
Research Findings ◽  
Selection Of

AbstractObjective: The purpose of this text is to identify approaches to defining and subsequently reviewing the definitions of uncertainty and risk as interdisciplinary terms which are of key importance in modern management.Methodology: The work is theoretical. The main method used in the research process was the analysis of scientific literature. A one-dimensional logical classification method was also used, in order to categorize approaches to defining uncertainty and risk, satisfying the exhaustive and mutually exclusive criteria in the selection of categories of approaches.Findings: The main results of the work are: 1) identification of approaches to defining uncertainty and risk, 2) interdisciplinary review of definitions of uncertainty and risk indicating the criteria to distinguish between the two, and 3) determination of the meaning of the terms uncertainty and risk in modern management.Value Added: Considering the approaches to defining uncertainty and risk taken from many fields and disciplines of science, this text is a compendium of theoretical knowledge for the proper understanding and meaning of these concepts in management.Recommendations: The research findings can have implications for both management theory as well as the practice of organization management.

scholarly journals Determination of occupational anxiety levels of teacher candidates studying in a different departmentsFarklı bölümlerde öğrenim gören öğretmen adaylarının mesleki kaygı düzeylerinin belirlenmesi

2018 ◽  
Vol 15 (4) ◽  
pp. 2168
Author(s):  
Duygu Harmandar Demirel ◽  
Emrah Serdar ◽  
Mehmet Demirel
Keyword(s):  
Prospective Teachers ◽  
Teacher Candidates ◽  
Sampling Methods ◽  
Personal Information ◽  
English Summary ◽  
Teaching Profession ◽  
Significant Difference ◽  
Research Findings ◽  
Anxiety Levels

The aim of this study is to determine the anxiety levels of the students studying in the teaching departments and to examine these according to different variables. The sample of the study consisted of 400 non-random sampling methods and 400 prospective teachers who were studying at Dumlupinar University. The personal information form created by the researchers and the data related to the pre-service teachers' concerns about the teaching profession were provided by Caba and Yalçınalp (2009). In the research findings: “Gender”, “Age”, “Satisfaction Status”, “Class”, “Faculty” and “Sports Making Status” showed a significant difference in “OAST” total scores (p <0.05). As a result, it can be concluded that the vocational anxiety levels of the teacher candidates studying in different departments differ according to some variables.Extended English summary is in the end of Full Text PDF (TURKISH) file. ÖzetBu araştırma ile öğretmenlik bölümlerinde okuyan öğrencilerinin mesleğe yönelik kaygı düzeylerini belirlemek ve bunu farklı değişkenlere göre incelemektir. Araştırmanın örneklemini seçkisiz olmayan örnekleme yöntemlerinden uygun örnekleme yoluyla seçilen ve Dumlupınar Üniversitesinde öğrenim görmekte olan 400 öğretmen adayı oluşturmaktadır. Çalışmada oluşturulan demografik bilgi formu ve öğretmen adaylarının öğretmenlik mesleğine yönelik kaygılarına ilişkin veriler Cabı ve Yalçınalp (2009) tarafından geliştirilen Öğretmen Adaylarına Yönelik Mesleki Kaygı Ölçeği (ÖAYMK) ile sağlanmıştır. Verilerin analizinde; betimsel istatistik yöntemler, Man Whitney U ve Kruskal Wallis testlerinden faydalanılmıştır. Araştırma bulgularında: “Cinsiyet”, “Yaş”, “Okuduğu Bölümden Memnun Olma Durumu”, “Sınıf”, “Fakülte” ve “Spor Yapma Durumu” göre “ÖAYMK” toplam puanlarında manidar farklılık bulunmuştur. Araştırmaya gore, öğretmen adaylarının meslekleri ile ilgili kaygı seviyelerinin değişkenlere göre farklılaştığı sonucuna varılabilir.

scholarly journals Using Symbols and Shapes for Analysis in Small Focus Group Research

2016 ◽  
Author(s):  
Oladokun Omojola
Keyword(s):  
Focus Group ◽  
Prima Facie ◽  
Group Method ◽  
Group Discussions ◽  
Focus Group Research ◽  
Group Research ◽  
Research Findings ◽  
Small Focus ◽  
Focus Group Method

Substantial literature exists to support the growing importance of focus group research, having been around for decades. Its ubiquity under the scholarship radar is not in doubt while the analyses of findings commonly seen are scholarly and significantly sophisticated. However, these analyses have been found to be limited in scope for fresh adopters of the focus group method, non-literate beneficiaries of research findings and business people who are critically averse to lengthy textual statements about outcomes. This article introduces the use of symbols as a means of analyzing responses from small focus group discussions. It attempts to demonstrate that using symbols can substantially assist in the prima facie determination of perceptions from a focus group membership, its patterns of agreement and disagreement, as well as the sequence of its discussions.

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