scholarly journals Drawing mechanisms for top coal in longwall top coal caving (LTCC): A review of two decades of literature

2021 ◽  
Author(s):  
Jiachen Wang ◽  
Shengli Yang ◽  
Weijie Wei ◽  
Jinwang Zhang ◽  
Zhengyang Song
Keyword(s):  
Coal Seam ◽  
Relevant Literature ◽  
Theoretical Models ◽  
Significant Loss ◽  
Future Research ◽  
Key Factors ◽  
Practical Applications ◽  
Open Questions ◽  
Physical Tests ◽  
Longwall Top Coal Caving

AbstractThis review details the state of the art in research on top coal drawing mechanisms in Longwall top coal caving (LTCC) by examining the relevant literature over the last two decades. It starts with an introduction of the brief history and basic procedures of LTCC. The framework of research on the drawing mechanism, basic concepts, and some theoretical models of LTCC are detailed in sect. research framework of top coal drawing mechanism. The authors note that the Top coal drawbody (TCD), Top coal boundary (TCB) and Top coal recovery ratio (TCRR) are key factors in the drawing mechanism. The Body–boundary–ratio (BBR) research system has been the classic framework for research over the last 20 years. The modified Bergmark–Roos model, which considers the effects of the supporting rear canopy, flowing velocity of top coal, and its shape factor, is optimal for characterizing the TCD. A 3D model to describe the TCB that considers the thicknesses of the coal seam and roof strata is reviewed. In sect. physical testing and numerical simulation, the physical tests and numerical simulations in the literature are classified for ease of bibliographical review, and classic conclusions regarding the drawing mechanism of top coal are presented and discussed with elaborate illustrations and descriptions. The deflection of the TCD is noted, and is caused by the shape of the rear canopy. The inclined coal seam always induces a larger TCD, and a deflection in the TCD has also been observed in it. The effects of the drawing sequence and drawing interval on the TCRR are reviewed, where a long drawing interval is found to lead to significant loss of top coal. Its flowing behavior and velocity distribution are also presented. Sect. practical applications of drawing mechanisms for LTCC mines 4 summarizes over 10 cases where the TCRR of LTCC mines improved due to the guidance of the drawing mechanism. The final section provides a summary of the work here and some open questions. Prospective investigations are highlighted to give researchers guidance on promising issues in future research on LTCC.

scholarly journals Influence Law of Interbedded Strata and Their Collapse on the Mining of Extremely Thick Coal Seam under Goaf

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Chunxu Ji ◽  
Yongkang Yang ◽  
Xingyun Guo ◽  
Tianhe Kang ◽  
Zefeng Guo
Keyword(s):  
Coal Seam ◽  
Water Inrush ◽  
Theoretical Models ◽  
Pressure Control ◽  
Future Research ◽  
Simulation Experiments ◽  
Thick Coal Seam ◽  
Movement Characteristics ◽  
Mining Pressure ◽  
The Stability

Interbedded strata and their collapse are vital to mining pressure control for extremely thick coal seam under goaf. To ensure the stability of the support and to avoid roof collapse, some traditional underground pressure theoretical models had been widely used in the control of surrounding rock and the selection of support. However, one of the challenges for extremely thick coal seam under goaf is that the abnormal disasters, such as support crushing and water inrush that were occurring frequently. To solve this problem, the movement characteristics of overburden rocks during the mining of extremely thick coal seam under the conditions of the interlayer thickness of 5 m and 40 m were studied by using the similar simulation experiments, while the numerical simulation experiments were carried out for the interval between coal seams of 15 m and 60 m, respectively. Finally, the structure and mechanical transfer mechanism of overburden in stope under different thickness interbedded strata were analyzed dynamically, and the condition of full-thickness connection between upper goaf and lower goaf and corresponding judgment criteria are obtained. These results can guide future research on the mechanical of extremely thick coal seam under goaf, which can provide a theoretical basis and engineering reference for similar projects.

System dynamics applications in performance measurement research: progress and challenges

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Olufunke Oladimeji ◽  
Jennifer Cross ◽  
Heather Keathley-Herring
Keyword(s):  
System Dynamics ◽  
Performance Measurement ◽  
Organizational Performance ◽  
Relevant Literature ◽  
Research Area ◽  
Strategic Decision ◽  
Research Progress ◽  
Future Research ◽  
Content Type ◽  
Practical Applications

PurposeA systematic literature review (SLR) was used to identify and analyze literature related to use of system dynamics (SD) applications in organizational performance measurement (PM) research. The purpose of this article is to present the results of a thematic analysis (TA) conducted to synthesize existing empirical evidence, investigate trends and evaluate developments in the research area.Design/methodology/approachA SLR was conducted resulting in a dataset of 97 articles in this research area. Using TA, major themes/subthemes were inductively synthesized to explore the current development and emerging trends and provide guidance for future research.FindingsThe TA resulted in seven themes in the research area – Enhancing knowledge, Approaches to operationalizing PM systems, Utilizing simulation models, Improving organizational outcomes, Achieving strategic alignment, Applying systems thinking and Identifying critical variables. The analysis suggests that although SD has the potential to improve PM systems, there are many limitations and challenges that must be addressed to improve implementation and practical applications. In addition, the results showed that much of the work is exploratory and many fail to fully validate their models suggesting that this research is still in an relatively early phase of development.Research limitations/implicationsThe results of this study are limited to the 97 articles identified using the SLR protocol. Although the search was designed to be comprehensive, there may be other relevant literature that was excluded. Further, the TA was limited to addressing the research questions.Practical implicationsA key insight for managers is that these tools would support decision-makers in understanding performance behaviors and identifying performance drivers for improvement. This suggests that stakeholders can adopt the approach to improve understanding and effectiveness of PM, and to enhance strategic decision-making.Originality/valueThis study provides a distinct and thorough analysis of this research area by conducting an inductive synthesis of developments and challenges and guidance for future research and practice. The resulting thematic model, identified code definitions and proposed framework of strategies to overcome challenges, provide a general overview and resource to support future studies in the research area and facilitate practical use of SD capabilities to support PM.

scholarly journals Key Factors to Green Building Technologies Adoption in Developing Countries: The Perspective of Chinese Designers

2018 ◽  
Vol 10 (11) ◽  
pp. 4135 ◽  
Author(s):  
Wei Wang ◽  
Shoujian Zhang ◽  
Yikun Su ◽  
Xinyang Deng
Keyword(s):  
Structural Equation Model ◽  
Structural Equation ◽  
Effective Means ◽  
Relevant Literature ◽  
Green Building ◽  
Equation Model ◽  
Future Research ◽  
Management Support ◽  
Key Factors ◽  
The Sustainable Development

Green building is deemed an effective means to realize the sustainable development of environment, economy and society in the construction industry. Green building technologies (GBTS) are important to realize green buildings. In order to make the application of GBTS be adopted and popularized effectively, it is especially important for us to gain thorough comprehension of the key problems that affect the adoption of GBTS. The target of this paper is to better understand the adoption of GBTS from the perspective of designers. This article utilizes a questionnaire to investigate Chinese architectural designers. Through establishing a structural equation model and an analysis of the survey data, the key factors influencing the adoption of GBTS by designers in the Design Company were found out. The results denote that the adoption motivation, the capability of GBTS, the knowledge structure and the defects of GBTS are the significant factors that affect designers’ adoption behaviors. However, the management support of GBTS has no significant effect on designers’ adoption behavior. The research results are helpful to improve adoption of GBTS in design units and accelerate the transformation of GBTS achievements. Additionally, they can promote the application of GBTS in the field of construction. Based on the quantitative theoretical model (the structural equation model), this paper finds out the key factors that affect the application of GBTS from the perspective of designers, enriching the theoretical methods of GBTS research and complementing the relevant literature of GBTS research. Future research will analyze the adoption behavior of GBTS from the point of other stakeholders and from the internal level of the design units.

A unique index with the explicit cost related to forecast

2016 ◽  
Vol 11 (2) ◽  
pp. 518-535
Author(s):  
Sanjay Sharma
Keyword(s):  
Supply Chain ◽  
Inventory Management ◽  
Relevant Literature ◽  
Demand Forecasting ◽  
Product Family ◽  
Basic Unit ◽  
Future Research ◽  
Content Type ◽  
Practical Applications ◽  
Unique Index

Purpose The present paper aims to draw an attention towards the inclusion of forecast related costs. Its main purpose is to initiate a new line of research/practice including the forecasting expenditure. Design/methodology/approach After a relevant review of supply chain/procurement/production planning related literature, it has been observed that the existing work lacks an explicit inclusion of the cost concerned with forecast. The increased cost of forecasting is expected to enhance the forecasting accuracy. At a higher level, product family is considered for the analysis. However, a basic unit of analysis is always a single item production/procurement situation. Therefore, this situation has been discussed analytically with the use of the fundamental equations and an explicit inclusion of forecasting cost for the first time in the relevant literature. Numerous practical applications have been discussed at strategic and operational level. A framework is also presented for future research in this area. Findings A specific contribution of the present paper is an approach towards a unique index for relative forecasting expenditure. The suggested index will be useful for comparison purpose. Also, it can be used as a benchmark that can be improved in future. Practical implications The case is explained when cycle time is invariant after discussing the other potential applications. Usefulness of the proposed methodology and the index is discussed for the business organizations operating independently or in the supply chains. Originality/value On the basis of the forecast, a production or procurement plan is generated in many of the industrial or business situations. In the context of supply chain/production/inventory management, focus is more on demand forecasting techniques or generation of the forecasts in the existing literature. However, the increased costs concerning forecasts are expected to provide more accurate prediction. Therefore, the originality lies in an inclusion of forecast related costs.

The complexity of human cooperation under indirect reciprocity

2021 ◽  
Vol 376 (1838) ◽  
Author(s):  
Fernando P. Santos ◽  
Jorge M. Pacheco ◽  
Francisco C. Santos
Keyword(s):  
Cognitive Complexity ◽  
Evolutionary Game ◽  
Theoretical Models ◽  
Future Research ◽  
Information Requirements ◽  
Honest Signalling ◽  
Indirect Reciprocity ◽  
Complex Information ◽  
Open Questions ◽  
Complex Information Processing

Indirect reciprocity (IR) is a key mechanism to understand cooperation among unrelated individuals. It involves reputations and complex information processing, arising from social interactions. By helping someone, individuals may improve their reputation, which may be shared in a population and change the predisposition of others to reciprocate in the future. The reputation of individuals depends, in turn, on social norms that define a good or bad action, offering a computational and mathematical appealing way of studying the evolution of moral systems. Over the years, theoretical and empirical research has unveiled many features of cooperation under IR, exploring norms with varying degrees of complexity and information requirements. Recent results suggest that costly reputation spread, interaction observability and empathy are determinants of cooperation under IR. Importantly, such characteristics probably impact the level of complexity and information requirements for IR to sustain cooperation. In this review, we present and discuss those recent results. We provide a synthesis of theoretical models and discuss previous conclusions through the lens of evolutionary game theory and cognitive complexity. We highlight open questions and suggest future research in this domain. This article is part of the theme issue ‘The language of cooperation: reputation and honest signalling’.

Helfen und Wohlbefinden aus psychologischer Perspektive

2021 ◽  
Vol 81 (6) ◽  
pp. 423-430
Author(s):  
Maike Luhmann
Keyword(s):  
Empirical Studies ◽  
Theoretical Models ◽  
Well Being ◽  
Self Determination Theory ◽  
Psychological Research ◽  
Self Determination ◽  
Future Research ◽  
Theoretical Frameworks ◽  
Open Questions ◽  
The Relationship

Abstract Psychological research has long been interested in whether helping can make people happy. This article summarizes empirical evidence and theoretical models on the relationship between helping and well-being. Empirical studies indicate a significant, but weak positive relationship between helping behaviors and well-being. The functional approach and self-determination theory are two theoretical frameworks that are particularly relevant for interdisciplinary investigations of this topic. The article concludes with a discussion of open questions and avenues for future research.

The Social Neuroscience of Cooperation

2018 ◽  
Author(s):  
Jay Joseph Van Bavel
Keyword(s):  
Theoretical Models ◽  
Brain Regions ◽  
Review Literature ◽  
Social Neuroscience ◽  
Future Research ◽  
A Value ◽  
Group Cooperation ◽  
Neural Processes ◽  
The Social ◽  
Cooperative Decision Making

We review literature from several fields to describe common experimental tasks used to measure human cooperation as well as the theoretical models that have been used to characterize cooperative decision-making, as well as brain regions implicated in cooperation. Building on work in neuroeconomics, we suggest a value-based account may provide the most powerful understanding the psychology and neuroscience of group cooperation. We also review the role of individual differences and social context in shaping the mental processes that underlie cooperation and consider gaps in the literature and potential directions for future research on the social neuroscience of cooperation. We suggest that this multi-level approach provides a more comprehensive understanding of the mental and neural processes that underlie the decision to cooperate with others.

Novel Coronavirus Disease (COVID-19): A Narrative Review Based on Current Status

2020 ◽  
Vol 18 ◽  
Author(s):  
Rina Das ◽  
Dinesh Kumar Mehta ◽  
Meenakshi Dhanawat
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Clinical Symptoms ◽  
Virus Disease ◽  
Relevant Literature ◽  
World Health ◽  
Current Status ◽  
Future Research ◽  
Treatment And Prevention ◽  
First Case ◽  
Novel Coronavirus

Abstract:: A novel virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), appeared and expanded globally by the end of year in 2019 from Wuhan, China, causing severe acute respiratory syndrome. During its initial stage, the disease was called the novel coronavirus (2019-nCoV). It was named COVID-19 by the World Health Organization (WHO) on 11 February 2020. The WHO declared worldwide the SARS-CoV-2 virus a pandemic on March 2020. On 30 January 2020 the first case of Corona Virus Disease 2019 (COVID-19) was reported in India. Now in current situation the virus is floating in almost every part of the province and rest of the globe. -: On the basis of novel published evidences, we efficiently summarized the reported work with reference to COVID-19 epidemiology, pathogen, clinical symptoms, treatment and prevention. Using several worldwide electronic scientific databases such as Pubmed, Medline, Embase, Science direct, Scopus, etc were utilized for extensive investigation of relevant literature. -: This review is written in the hope of encouraging the people successfully with the key learning points from the underway efforts to perceive and manage SARS-CoV-2, suggesting sailent points for expanding future research.

Further investigations on Fujimoto type strong uniqueness polynomials

Filomat ◽  
2017 ◽  
Vol 31 (16) ◽  
pp. 5203-5216
Author(s):  
Abhijit Banerjee ◽  
Bikash Chakraborty ◽  
Sanjay Mallick
Keyword(s):  
Meromorphic Functions ◽  
Future Research ◽  
Strong Uniqueness ◽  
Open Questions

Taking the question posed by the first author in [1] into background, we further exhaust-ably investigate existing Fujimoto type Strong Uniqueness Polynomial for Meromorphic functions (SUPM). We also introduce a new kind of SUPM named Restricted SUPM and exhibit some results which will give us a new direction to discuss the characteristics of a SUPM. Moreover, throughout the paper, we pose a number of open questions for future research.

Cancer and Cancer Treatment-Related Cognitive Impairment

2019 ◽  
pp. 60-83
Author(s):  
James C.  Root ◽  
Elizabeth Ryan ◽  
Tim A. Ahles
Keyword(s):  
Cancer Survivors ◽  
Cancer Treatment ◽  
Clinical Presentation ◽  
Functional Neuroimaging ◽  
Theoretical Models ◽  
Future Research ◽  
Cognitive Changes ◽  
Central Nervous System Cancer ◽  
Pharmacologic Treatments

As the population of cancer survivors has grown into the millions, there is increasing emphasis on understanding how late effects of treatment impact survivors’ ability return to work/school, ability to function and live independently, and overall quality of life. Cognitive changes are one of the most feared problems among cancer survivors. This chapter describes the growing literature examining cognitive changes associated with non-central nervous system cancer and cancer treatment. Typical elements of cancer treatment are discussed, followed by a description of clinical presentation, self-reported and objectively assessed cognitive findings, and results of structural and functional neuroimaging research. Genetic and other risk factors for cognitive decline following treatment are identified and discussed, together with biomarkers and animal models of treatment-related effects. This is followed by a discussion of behavioral and pharmacologic treatments. Finally, challenges and recommendations for future research are provided to help guide subsequent research and theoretical models.

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