The complexity of calcareous deposits processes in a marine environment results in simultaneous effects of the following parameters： temperature, polarization potential, interfacial pH, chemical composition, etc.. Th...The complexity of calcareous deposits processes in a marine environment results in simultaneous effects of the following parameters： temperature, polarization potential, interfacial pH, chemical composition, etc.. The comprehension of these processes implies studies in artificial seawater and a follow-up of the parameters by voltarnperometry and chronoamperometry. Calcareous deposits electrochemically are very often used to follow up the evolution of scale deposition in desalination circuits. Again, the scale formation is brought about by electrochemical reduction of dissolved oxygen. The hydroxyl ions formed on the metallic surface engender a rise of interfacial pH which causes calcareous deposition （CaCOs and Mg（OH）2）. This reaction goes with reaction of hydrogen evolution which could disrupt the formed deposit, A study is carried out in a solution of seawater ASTM without calcium and without magnesium （so that the deposit will not be formed） on a titanium rotating disk electrode monitored between 300 and 1000 rpm. Study shows that Levich criterion is checked for the four values of selected potential on the diffusion plateau and a very cathodic polarization potential and a high temperature favors hydrogen current rate.展开更多
Currently,the reduction of weight in automotive is a very important topic to reduce the air pollution.In this context,the purpose of the present paper is to analyze a real case study through a comparison of the enviro...Currently,the reduction of weight in automotive is a very important topic to reduce the air pollution.In this context,the purpose of the present paper is to analyze a real case study through a comparison of the environmental impacts between a conventional steel bumper and a polyester prototype.In the first part of this work,a door-to-door life-cycle assessment methodology was used throughout the study of the component manufacturing phase.The SimaPro 7.1 software is used to evaluate the impacts of both bumpers on the environment and health.The second part is devoted to dust analysis from the polyester workshop.The obtained results have allowed us to show the company that its choice of steel substitution by the polyester is advantageous for certain impacts including the impact of climate change,but unfortunately there may be,given the working conditions of the polyester workshop,a transfer of impact,since we will end up with a risk of health(irritations,cancers)for the workers.LCA has proven to be a very useful tool for validating a redesigned automotive component from an environmental point of view;from this case study,several recommendations were made for the company to design environmentally friendly components,and ecodesign should be introduced into the company’s procedures.展开更多
文摘The complexity of calcareous deposits processes in a marine environment results in simultaneous effects of the following parameters： temperature, polarization potential, interfacial pH, chemical composition, etc.. The comprehension of these processes implies studies in artificial seawater and a follow-up of the parameters by voltarnperometry and chronoamperometry. Calcareous deposits electrochemically are very often used to follow up the evolution of scale deposition in desalination circuits. Again, the scale formation is brought about by electrochemical reduction of dissolved oxygen. The hydroxyl ions formed on the metallic surface engender a rise of interfacial pH which causes calcareous deposition （CaCOs and Mg（OH）2）. This reaction goes with reaction of hydrogen evolution which could disrupt the formed deposit, A study is carried out in a solution of seawater ASTM without calcium and without magnesium （so that the deposit will not be formed） on a titanium rotating disk electrode monitored between 300 and 1000 rpm. Study shows that Levich criterion is checked for the four values of selected potential on the diffusion plateau and a very cathodic polarization potential and a high temperature favors hydrogen current rate.
文摘Currently,the reduction of weight in automotive is a very important topic to reduce the air pollution.In this context,the purpose of the present paper is to analyze a real case study through a comparison of the environmental impacts between a conventional steel bumper and a polyester prototype.In the first part of this work,a door-to-door life-cycle assessment methodology was used throughout the study of the component manufacturing phase.The SimaPro 7.1 software is used to evaluate the impacts of both bumpers on the environment and health.The second part is devoted to dust analysis from the polyester workshop.The obtained results have allowed us to show the company that its choice of steel substitution by the polyester is advantageous for certain impacts including the impact of climate change,but unfortunately there may be,given the working conditions of the polyester workshop,a transfer of impact,since we will end up with a risk of health(irritations,cancers)for the workers.LCA has proven to be a very useful tool for validating a redesigned automotive component from an environmental point of view;from this case study,several recommendations were made for the company to design environmentally friendly components,and ecodesign should be introduced into the company’s procedures.
