Creep and superplasticity were investigated by testing a fine-grained extruded Mg–Zn–Zr magnesium alloy under a wide range of applied stress in the temperature range between 100 and 300 ℃. Grain boundary sliding be...Creep and superplasticity were investigated by testing a fine-grained extruded Mg–Zn–Zr magnesium alloy under a wide range of applied stress in the temperature range between 100 and 300 ℃. Grain boundary sliding became the dominating mechanism at 200 ℃, leading to a true superplastic behaviour at 300 ℃, where superplasticity was attained even under relatively high strain rates （5×10-3 s-1 ）. By contrast, for lower temperatures, the straining process was controlled by dislocation climb. A comprehensive model, taking into account the simultaneous operation of the different mechanisms, was developed to describe the strain rate dependence on applied stress.展开更多
This paper presents the results of a sensitivity study carried out to investigate the performances of two commercial codes,OLGA and LedaFlow,used to model the wax deposition process in pipelines under multiphase flow....This paper presents the results of a sensitivity study carried out to investigate the performances of two commercial codes,OLGA and LedaFlow,used to model the wax deposition process in pipelines under multiphase flow.Reliable simulations of the phenomenon are essential to properly design pipelines and to adopt cost-effective strategies for prevention and removal of wax deposits,reducing the risks of blockage.The main limit of the available models is that their predictions depend on a number of parameters which are usually adjusted to fit the experimental data obtained from laboratory deposition tests.Since a reliable upscale criterion has not been developed yet,model predictions have been more suitably validated using real field data,reported in literature.The performances of the commercial codes in modelling wax precipitation and deposition have been compared to each other.展开更多
This paper presents the development and application of an innovative code to extract in an automated way data from the thermo-hydraulic simulator Olga.The results show that the tool can significantly reduce the time n...This paper presents the development and application of an innovative code to extract in an automated way data from the thermo-hydraulic simulator Olga.The results show that the tool can significantly reduce the time needed for the data extraction procedure and increase the reliability of results due to the fact that there is no more the need of the human operator.Moreover,during the data extraction phase,the Olga code is available for running different simulations allowing to optimize the use of this resource.展开更多
The Oil&Gas industry has continuously increased its requirements and together with the high complexity of technological systems and the higher competitiveness of markets,has compelled providers to implement adequa...The Oil&Gas industry has continuously increased its requirements and together with the high complexity of technological systems and the higher competitiveness of markets,has compelled providers to implement adequate management strategies for these systems in order to improve their availability and productivity to meet those more demanding criteria.In this context,the complex of RAM factors constitute a strategic approach for integrating reliability,availability and maintainability,by using methods,tools and engineering techniques(Mean Time to Failure,Equipment down Time and System Availability values)to identify and quantify equipment and system failures that prevent the achievement of the productive objectives.The application of such methodologies requires a deep experience and know-how together with the possibility of acquiring and processing data in operating conditions.This paper presents the most relevant aspects and findings of a study conducted for assessing the operational performance of a reciprocating compressor system package installed and used in the oil and gas'industries.The study was based on the analysis of the behaviour of states defined for each individual parts and component of reciprocating compressor and also aimed to identify and evaluate the effects of RAMtype factors and was conducted in collaboration with a private company that,for privacy reasons,will be named RC company.The Methodologies procedures used in this descriptive study were the bibliographical research,documentary and content analysis of the main literature.Adopting the most suitable maintenance strategy is one of the main challenges that maintenance managers face.The main purpose of this work is to propose a new approach to evaluate maintenance strategies.In this study,three criteria called reliability,availability and maintainability(RAM)have been employed to compare to future maintenance strategies.展开更多
基金partly financially supported by Ort Braude College of Engineering, Israel
文摘Creep and superplasticity were investigated by testing a fine-grained extruded Mg–Zn–Zr magnesium alloy under a wide range of applied stress in the temperature range between 100 and 300 ℃. Grain boundary sliding became the dominating mechanism at 200 ℃, leading to a true superplastic behaviour at 300 ℃, where superplasticity was attained even under relatively high strain rates （5×10-3 s-1 ）. By contrast, for lower temperatures, the straining process was controlled by dislocation climb. A comprehensive model, taking into account the simultaneous operation of the different mechanisms, was developed to describe the strain rate dependence on applied stress.
文摘This paper presents the results of a sensitivity study carried out to investigate the performances of two commercial codes,OLGA and LedaFlow,used to model the wax deposition process in pipelines under multiphase flow.Reliable simulations of the phenomenon are essential to properly design pipelines and to adopt cost-effective strategies for prevention and removal of wax deposits,reducing the risks of blockage.The main limit of the available models is that their predictions depend on a number of parameters which are usually adjusted to fit the experimental data obtained from laboratory deposition tests.Since a reliable upscale criterion has not been developed yet,model predictions have been more suitably validated using real field data,reported in literature.The performances of the commercial codes in modelling wax precipitation and deposition have been compared to each other.
文摘This paper presents the development and application of an innovative code to extract in an automated way data from the thermo-hydraulic simulator Olga.The results show that the tool can significantly reduce the time needed for the data extraction procedure and increase the reliability of results due to the fact that there is no more the need of the human operator.Moreover,during the data extraction phase,the Olga code is available for running different simulations allowing to optimize the use of this resource.
文摘The Oil&Gas industry has continuously increased its requirements and together with the high complexity of technological systems and the higher competitiveness of markets,has compelled providers to implement adequate management strategies for these systems in order to improve their availability and productivity to meet those more demanding criteria.In this context,the complex of RAM factors constitute a strategic approach for integrating reliability,availability and maintainability,by using methods,tools and engineering techniques(Mean Time to Failure,Equipment down Time and System Availability values)to identify and quantify equipment and system failures that prevent the achievement of the productive objectives.The application of such methodologies requires a deep experience and know-how together with the possibility of acquiring and processing data in operating conditions.This paper presents the most relevant aspects and findings of a study conducted for assessing the operational performance of a reciprocating compressor system package installed and used in the oil and gas'industries.The study was based on the analysis of the behaviour of states defined for each individual parts and component of reciprocating compressor and also aimed to identify and evaluate the effects of RAMtype factors and was conducted in collaboration with a private company that,for privacy reasons,will be named RC company.The Methodologies procedures used in this descriptive study were the bibliographical research,documentary and content analysis of the main literature.Adopting the most suitable maintenance strategy is one of the main challenges that maintenance managers face.The main purpose of this work is to propose a new approach to evaluate maintenance strategies.In this study,three criteria called reliability,availability and maintainability(RAM)have been employed to compare to future maintenance strategies.
