scholarly journals Numerical Simulation of Seepage and Stability of Tailings Dams: A Case Study in Lixi, China

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 742
Author(s):  
Chen Zhang ◽  
Junrui Chai ◽  
Jing Cao ◽  
Zengguang Xu ◽  
Yuan Qin ◽  
...  
Keyword(s):  
Safety Factor ◽  
Working Conditions ◽  
Finite Element Models ◽  
Tailings Dam ◽  
Slope Ratio ◽  
Seepage Field ◽  
Upstream Slope ◽  
Tailings Dams ◽  
Dimensional Finite Element

The purpose of establishing a tailings dam is to safely store tailings to protect the natural environment from damage. Accidents at tailings dams are frequent, however, with serious consequences of not only threats to life and property but also the pollution of the environment. Many tailings dam accidents are caused by seepage failure. In this paper, the object of the case study is the Lixi tailings dam. Three- and two-dimensional finite element models are established. The seepage field of the project under different working conditions is simulated and the position of the phreatic line is obtained. The safety factors under different working conditions are obtained by combining the seepage field with the stable surface. Finally, the influence of different dry and upstream slope ratio on seepage and stability of tailings dam is obtained. The results show that the longer the length of the dry beach, the lower the phreatic line and the greater the safety factor. The higher the upstream slope ratio, the lower the phreatic line and the greater the safety factor.

Influence of Berm Number on Safety Factor of Tailings Dam

2011 ◽  
Vol 374-377 ◽  
pp. 2488-2492 ◽  
Author(s):  
Chuan Wang Song ◽  
Guang Ming Yu ◽  
Pei Shou Wang
Keyword(s):  
Safety Factor ◽  
Research Field ◽  
Dam Safety ◽  
Tailings Dam ◽  
Important Research ◽  
Safety Factors ◽  
Important Indicator ◽  
Influence Analysis ◽  
Dam Impact ◽  
Tailings Dams

Tailings dam safety has always been an important research field of geotechnical engineering world, and research on safety factor of dam is an important indicator of stability of tailings dams. In this paper assumed that Sweden arc method and simplified Bishop method were used to analyze influence of berm number on safety factor of tailings dam in some condition. Results showed that change of berm number had an impact on total safety factor of dam; Impact of change of berm number on safety factors was also different at different intervals. The influence analysis of changes of berm number on safety factor of dam had directive significance for design and construction on site.

Progressive Law, Activism, and Lawyering in an Age of Preemption

2021 ◽  
Vol 46 (1) ◽  
pp. 252-267
Author(s):  
Rashmi Dyal-Chand
Keyword(s):  
Working Conditions ◽  
Local Level ◽  
Global Supply Chain ◽  
Environmental Movements ◽  
Improve Working ◽  
Detailed History ◽  
History Of ◽  
State And Local ◽  
Core Questions

Preemption is one of the most important legal doctrines for today’s progressives to understand because of its power to constrain progressive policymaking and social movement lawyering at the state and local level. By examining the detailed history of a decades-long campaign by the labor and environmental movements to improve working conditions in an industry at the heart of the global supply chain, Scott L. Cummings’s Blue and Green: The Drive for Justice at America’s Port (2018) provides a case study about the doctrine and impacts of preemption. The study also inspires lawyers and activists alike to reexamine core questions of factual relevance, representation and voice, and precedent.

Numerical Analysis of Safety on Waste-Dumping Cover-Slope out of the Tailings Dam

2014 ◽  
Vol 501-504 ◽  
pp. 178-184
Author(s):  
Kai Yang ◽  
Shu Ran Lv ◽  
Chun Xue Wang
Keyword(s):  
Production Cost ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Bottom Layer ◽  
Tailings Dam ◽  
Waste Dump ◽  
Mining Companies ◽  
Tailings Dams ◽  
Before And After ◽  
Dump Slope

Mining companies intend to solve the problem of waste dump and reduce the production cost by dumping a large number of waste soils to cover slope outside the running tailings. Therefore, in order to discuss the safety of waste dump slope covering in front of the tailings dam, numerical method was adopted to study the seepage-line change law, the pore water pressure and anti-sliding safety before and after the waste dump covering out of tailings dam. The researches show that the key to waste-dump slope safety are the drainage performance of waste dump bottom layer and the anti-sliding safety of waste dump soil. The appropriate waste dump slope work can improves the tailings dams safety and solves the waste dump problem in mining production.

Novel and simplified optimisation pathway using response surface and design of experiments methodologies for dental implants based on the stress of the cortical bone

2021 ◽  
pp. 095441192110253
Author(s):  
João PO Freitas ◽  
Bruno Agostinho Hernandez ◽  
Paulo J Paupitz Gonçalves ◽  
Edmea C Baptista ◽  
Edson A Capello Sousa
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Design Of Experiments ◽  
Cortical Bone ◽  
Response Surface ◽  
Dental Implants ◽  
Finite Element Models ◽  
Long Term Treatment ◽  
Dimensional Finite Element ◽  
Surrounding Bone

Dental implants are widely used as a long-term treatment solution for missing teeth. A titanium implant is inserted into the jawbone, acting as a replacement for the lost tooth root and can then support a denture, crown or bridge. This allows discreet and high-quality aesthetic and functional improvement, boosting patient confidence. The use of implants also restores normal functions such as speech and mastication. Once an implant is placed, the surrounding bone will fuse to the titanium in a process known as osseointegration. The success of osseointegration is dependent on stress distribution within the surrounding bone and thus implant geometry plays an important role in it. Optimisation analyses are used to identify the geometry which results in the most favourable stress distribution, but the traditional methodology is inefficient, requiring analysis of numerous models and parameter combinations to identify the optimal solution. A proposed improvement to the traditional methodology includes the use of Design of Experiments (DOE) together with Response Surface Methodology (RSM). This would allow for a well-reasoned combination of parameters to be proposed. This study aims to use DOE, RSM and finite element models to develop a simplified optimisation analysis method for dental implant design. Drawing on data and results from previous studies, two-dimensional finite element models of a single Branemark implant, a multi-unit abutment, two prosthetic screws, a prosthetic crown and a region of mandibular bone were built. A small number of combinations of implant diameter and length were set based on the DOE method to analyse the influence of geometry on stress distribution at the bone-implant interface. The results agreed with previous studies and indicated that implant length is the critical parameter in reducing stress on cortical bone. The proposed method represents a more efficient analysis of multiple geometrical combinations with reduced time and computational cost, using fewer than a third of the models required by the traditional methods. Further work should include the application of this methodology to optimisation analyses using three-dimensional finite element models.

scholarly journals Formação inicial e condições de trabalho de professores de Ciências da Natureza: estudo de elementos relacionados à formação continuada

2017 ◽  
Vol 6 (1) ◽  
Author(s):  
Carlos Ventura Fonseca ◽  
Fabiane De Andrade Ramos
Keyword(s):  
Working Conditions ◽  
Rio Grande ◽  
Natural Sciences ◽  
Rio Grande Do Sul ◽  
National Guidelines ◽  
Academic Production ◽  
Continued Education ◽  
Professional Profile ◽  
Multiple Case

Resumo: A proposta deste artigo é descrever uma investigação qualitativa, caracterizada como estudo de casos múltiplos, que envolveu sete professores da área de Ciências da Natureza que atuam em uma escola pública estadual do Rio Grande do Sul. Objetivou-se que esses movimentos de pesquisa fornecessem elementos considerados indicadores específicos para a construção de ações futuras de formação continuada. Tendo-se como referência a produção acadêmica contemporânea da área educacional e as diretrizes nacionais para as licenciaturas, foi construído e aplicado um questionário com questões abertas e fechadas, utilizando-se análise de conteúdo como técnica interpretativa das respostas descritivas. As análises efetuadas revelaram aproximações e afastamentos entre as visões dos sujeitos sobre as virtudes e fraquezas pertencentes aos respectivos cursos de formação inicial, bem como especificidades das condições de trabalho e do perfil profissional de cada docente que apresenta potencial para nortear, ainda que de modo parcial, o planejamento desejado.Palavras-chave: Formação docente. Trabalho docente. Educação em Ciências. INITIAL EDUCATION AND WORKING CONDITIONS OF NATURAL SCIENCES TEACHERS: STUDY OF ELEMENTS RELATED TO CONTINUED EDUCATION  Abstract: The purpose of this article is to describe a qualitative investigation characterized as a multiple case study involving seven professors from the Natural Sciences area who work in a state public school in Rio Grande do Sul, Brazil. These research movements were designed to provide elements regarded as specific indicators in which to base the construction of future actions for continued education. Referring to the contemporary academic production within educational area and national guidelines for undergraduate courses, a questionnaire with open and closed questions was designed and applied using content analysis as an interpretive technique of descriptive answers. Analyses carried out revealed approximations and withdrawals between the subjects' views on the virtues and weaknesses belonging to respective initial education courses, as well as specificities of working conditions and  professional profile of each teacher who has the potential to guide albeit in partially the desired planning.Keywords: Teacher education. Teaching Work. Science Education.

Smoking Bans and Shop Floor Resistance during the Early Twentieth Century

2016 ◽  
Author(s):  
Gregory Wood
Keyword(s):  
Twentieth Century ◽  
Working Conditions ◽  
Mass Production ◽  
Large Mass ◽  
Shop Floor ◽  
Smoking Bans ◽  
Early Twentieth Century ◽  
Paper Company ◽  
Time Away

This chapter explores early-twentieth-century employers' opposition to smoking in the workplace, focusing on a case study of smoking practices and shop floor disputes at the Hammermill Paper Company in Erie, Pennsylvania, during the long, hot summer of 1915. Uniquely detailed reports of working conditions and workers' behaviors in this large mass-production factory, written by a pair of curious labor spies, documented nicely the ongoing efforts of many workers to circumvent the company's prohibition of smoking. In response to the refusal of management to allow smoking, workers improvised an assortment of surreptitious strategies that would allow them to smoke at work and enjoy time away from their jobs. As the Hammermill case illustrates, the wide extent of worker subversion made the no-smoking rule a dead letter, much to the constant frustration of management and the spies themselves.

Case Study of the St. Paul Companies Virtual Office for the Risk Control Division

2011 ◽  
pp. 60-71
Author(s):  
Nancy Johnson
Keyword(s):  
Working Conditions ◽  
Risk Control ◽  
Working Environment ◽  
Personal Lives ◽  
Virtual Office ◽  
Office Space ◽  
Construction Risk ◽  
Remote Sites ◽  
Control Division

The St. Paul Companies has successfully implemented a virtual office (VO) working environment for their US distributed construction risk control and commercial risk control employees over the past six years. The program goals of operating more cost effectively, increasing contact of the risk control specialists with their customers, and reducing office space costs for The St. Paul Companies have been met. There are many good practices that have been developed over the six years of offering the program, and more refinements and changes planned. As the communications and computer technologies advance, facilitation of working from remote sites improves. While it is easier for employees to work from remote sites, maintaining the boundaries between work and personal lives is more challenging. Improving the VO employees’ and corporate employees’ understanding of the other’s working conditions is necessary to improve relationships and the acceptance of change. The concept of VO work is well established within the organization, and the demand for it is growing.

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