An analysis of the present and of the future of the refractories industry is being presented , considering some important technical, economical, human and environmental issues , on a worldwide basis. Refractories are ...An analysis of the present and of the future of the refractories industry is being presented , considering some important technical, economical, human and environmental issues , on a worldwide basis. Refractories are still neededas confinement materials to prevent heat and mass transferlosses in many diverse manufacturing industries , and will remain so , but the main challenges , this industry do needto meet, are to adjust to an overcapacity production , to cope with new needs of the customers , in particular the'outsourcing' , which is a new customer / supplier relationship being adopted by many of them, and to keep the research and development alive in a more and more competitive arena. Among the direct consequences , are the need to keep the education world in refractory engineering training alive and to cope with macro and micro projects to change the image of the Refractories , from a commodity material to a sophisticated 'high-tech' composite material . Some suggestions are provided in the text.展开更多
Low cement (LC) and ultra low cement (ULC) bauxite SiC castables are important and high performance monolithic refractories and they have been widely used in iron making and incinerator linings. In this work, rheol...Low cement (LC) and ultra low cement (ULC) bauxite SiC castables are important and high performance monolithic refractories and they have been widely used in iron making and incinerator linings. In this work, rheological behavior of LC and ULC bauxite based SiC containing castables has been studied, including the effects of SiC content and cement content on rheological properties of the castables. The results show that with an increase of SiC and cement content, rheological properties of the castables deteriorate. On the other hand, moderate amounts of SiC (4%～8%) and of calcium aluminate cement (2%～4%) have very slight influence on rheological properties, (i.e. when the castables are sheared their torque and yield torque only slightly increase with the shearing speed). The rheological characteristics of the castables follow Bingham fluid and always show shear thinning behavior.展开更多
A new sandwich test has been developed to measure the adherence of cement clinker on basic refractories to test their coatability,Statistical desings of experiment method-ology were employed for evaluations of the san...A new sandwich test has been developed to measure the adherence of cement clinker on basic refractories to test their coatability,Statistical desings of experiment method-ology were employed for evaluations of the sandwich test.Three fractional factorial tests and one full factorial test were executed to efficiently generate data that reveal the significance of the major factors and the ruggedness to the minor factors .Its repeatability and reproducibility have been statistically confirmed to be acceptable,Evaluations on various basic bricks by the sandwich test reflect their coating performance in rotary kiln.展开更多
Advanced X-ray spectroscopic methods provide unique and critical data to study matter under extreme environmental conditions induced by high-intensity and high-energy lasers.The aim of this paper is to contribute to a...Advanced X-ray spectroscopic methods provide unique and critical data to study matter under extreme environmental conditions induced by high-intensity and high-energy lasers.The aim of this paper is to contribute to a contemporary discussion of the role of X-ray spectroscopy in the investigation of radiative properties of strongly coupled,highly correlated,and frequently weakly emissive plasma systems formed in matter irradiated by sub-petawatt and petawatt class lasers.After reviewing the properties of different X-ray crystal spectrometers,high-resolution X-ray diagnostic methods are surveyed with respect to their potential to study plasmainduced and externally induced radiation fields,suprathermal electrons,and strong electromagnetic field effects.Atomic physics in dense plasmas is reviewed with emphasis on non-Maxwellian non-LTE atomic kinetics,quasi-stationary and highly-transient conditions,hollow ion X-ray emission,and field-perturbed atoms and ions.Finally,we discuss the role of X-ray free electron lasers with respect to supplementary investigations of matter under extreme conditions via the use of controlled high-intensity radiation fields.展开更多
Rheplpgy of castables is greatly affected and controlled by rheological behavior of their matrix. In this work ,the rheological properties of bauxite-based castable matrix have been studied. The effects of super-fine ...Rheplpgy of castables is greatly affected and controlled by rheological behavior of their matrix. In this work ,the rheological properties of bauxite-based castable matrix have been studied. The effects of super-fine silica and alumina addition , water/ cement ratio, dispersants and bauxite particle-size on viscosity, shear rate and shear stress of the slur-ries have been investigated . Based on these results, the range of optimum composition of the matrix with good rheological behavior has been obtained.展开更多
Oxidation of the added graphite and the bonding carbon is an imortant degradation mode of doloma-carbon refractories in service,In this work,the behavior and effects of various boron bearing materials(CaB6,ZrB2,Bc and...Oxidation of the added graphite and the bonding carbon is an imortant degradation mode of doloma-carbon refractories in service,In this work,the behavior and effects of various boron bearing materials(CaB6,ZrB2,Bc and colemanite)as an-tioxidants have been investigated and compared to the effect of Al-Mg alloy,For CaO-MgO-C mate-rials,the effect of boron bearingadditives is better than Al-Mg alloy,The borate melt formed at high temperature would retard or prevent carbon oxidation,thus contributing to improved oxidation resistance,Preliminary investigations on the effect of boron bearing additives and Al-Mg alloy on corrosion resistance of doloma-carbon materials have indicated that simultaneous addition of the two types of additives would lead to pronounced improvement of slag corrosion resistance.展开更多
The parameters influencing the process of carbon oxidation in magnesia-carbon refracto-ries are reviewed.A typology of their oxidation resistance measurements is then presented;four different method are discussed in d...The parameters influencing the process of carbon oxidation in magnesia-carbon refracto-ries are reviewed.A typology of their oxidation resistance measurements is then presented;four different method are discussed in details.No agreement has been reached yet on a standard-ized test method.So far,oxidation resistance describes a process more than a property.展开更多
Water addition has direct impact on castables and needs to be under control placement and properties, In this work, two rheological properties, flow resistance and torque viscosity, have been measured against time, wi...Water addition has direct impact on castables and needs to be under control placement and properties, In this work, two rheological properties, flow resistance and torque viscosity, have been measured against time, with different water addition in the same bauxile-based LC Castable mix. The flow resistance indicates the mobility, whereas the torque viscosity dictates the stability of a castable during installation. It has been observed that with 6.0wt% water addition, such a mix possesses good vibration castable characteristics; with 6.5 wt%, it shows good self-flow castable characteristics; and with 7.0 wt%, it can be a good pumpable castable, in every case with comparable mechanical properties. While with 7.5 wt% water addition, the properties of such castable are definitively impaired.展开更多
In the present work, we used the technique of “low energy ion implantation + swift; heavy ion irradiation ”to investigate huge electronic excitations induced modification in N-doped graphite-like-carbon.
In this work, the rheological behavior of ultra-low cement alumina-based castables with addition of flake graphite and extruded graphite pellets has been investigated by using IBB rheometer. Emphasis has been laid on ...In this work, the rheological behavior of ultra-low cement alumina-based castables with addition of flake graphite and extruded graphite pellets has been investigated by using IBB rheometer. Emphasis has been laid on the influence of the type and amount of carbon addition on rheological properties of the alumina-based castables and the results are compared with corresponding alumina castable samples without any carbon addition. It is found that alumina-based castables with extruded graphite pellets have good rheological behavior and flowability with lower water demand (<6.3%) and no segregation during the shearing of castable.展开更多
The authors establish the existence of a large class of mathematical entropies (the so-called weak entropies) associated with the Euler equations for an isentropic, compressible fluid governed by a general pressure la...The authors establish the existence of a large class of mathematical entropies (the so-called weak entropies) associated with the Euler equations for an isentropic, compressible fluid governed by a general pressure law. A mild assumption on the behavior of the pressure law near the vacuum is solely required. The analysis is based on an asymptotic expansion of the fundamental solution (called here the entropy kernel) of a highly singular Euler- Poisson-Darboux equation. The entropy kernel is only Holder continuous and its regularity is carefully inversti- gated. Relying on a notion introduced earlier by the authors, it is also proven that, for the Euler equations, the set of eatropy flux-splittings coincides with the set of entropies-entropy fluxes. There results imply the existence of a flux-splitting consistent with all of the entropy inequalities.展开更多
文摘An analysis of the present and of the future of the refractories industry is being presented , considering some important technical, economical, human and environmental issues , on a worldwide basis. Refractories are still neededas confinement materials to prevent heat and mass transferlosses in many diverse manufacturing industries , and will remain so , but the main challenges , this industry do needto meet, are to adjust to an overcapacity production , to cope with new needs of the customers , in particular the'outsourcing' , which is a new customer / supplier relationship being adopted by many of them, and to keep the research and development alive in a more and more competitive arena. Among the direct consequences , are the need to keep the education world in refractory engineering training alive and to cope with macro and micro projects to change the image of the Refractories , from a commodity material to a sophisticated 'high-tech' composite material . Some suggestions are provided in the text.
文摘Low cement (LC) and ultra low cement (ULC) bauxite SiC castables are important and high performance monolithic refractories and they have been widely used in iron making and incinerator linings. In this work, rheological behavior of LC and ULC bauxite based SiC containing castables has been studied, including the effects of SiC content and cement content on rheological properties of the castables. The results show that with an increase of SiC and cement content, rheological properties of the castables deteriorate. On the other hand, moderate amounts of SiC (4%～8%) and of calcium aluminate cement (2%～4%) have very slight influence on rheological properties, (i.e. when the castables are sheared their torque and yield torque only slightly increase with the shearing speed). The rheological characteristics of the castables follow Bingham fluid and always show shear thinning behavior.
文摘A new sandwich test has been developed to measure the adherence of cement clinker on basic refractories to test their coatability,Statistical desings of experiment method-ology were employed for evaluations of the sandwich test.Three fractional factorial tests and one full factorial test were executed to efficiently generate data that reveal the significance of the major factors and the ruggedness to the minor factors .Its repeatability and reproducibility have been statistically confirmed to be acceptable,Evaluations on various basic bricks by the sandwich test reflect their coating performance in rotary kiln.
基金One of the authors(O.R.)acknowledges support from the Czech Republic Ministry of Education,Youth and Sports within targeted support of Large Infrastructures,ELI Beamlines Project No.LQ1606 of the National Programme of Sustainability II,and Prague Asterix Laser System Project No.LM2015083.
文摘Advanced X-ray spectroscopic methods provide unique and critical data to study matter under extreme environmental conditions induced by high-intensity and high-energy lasers.The aim of this paper is to contribute to a contemporary discussion of the role of X-ray spectroscopy in the investigation of radiative properties of strongly coupled,highly correlated,and frequently weakly emissive plasma systems formed in matter irradiated by sub-petawatt and petawatt class lasers.After reviewing the properties of different X-ray crystal spectrometers,high-resolution X-ray diagnostic methods are surveyed with respect to their potential to study plasmainduced and externally induced radiation fields,suprathermal electrons,and strong electromagnetic field effects.Atomic physics in dense plasmas is reviewed with emphasis on non-Maxwellian non-LTE atomic kinetics,quasi-stationary and highly-transient conditions,hollow ion X-ray emission,and field-perturbed atoms and ions.Finally,we discuss the role of X-ray free electron lasers with respect to supplementary investigations of matter under extreme conditions via the use of controlled high-intensity radiation fields.
文摘Rheplpgy of castables is greatly affected and controlled by rheological behavior of their matrix. In this work ,the rheological properties of bauxite-based castable matrix have been studied. The effects of super-fine silica and alumina addition , water/ cement ratio, dispersants and bauxite particle-size on viscosity, shear rate and shear stress of the slur-ries have been investigated . Based on these results, the range of optimum composition of the matrix with good rheological behavior has been obtained.
文摘Oxidation of the added graphite and the bonding carbon is an imortant degradation mode of doloma-carbon refractories in service,In this work,the behavior and effects of various boron bearing materials(CaB6,ZrB2,Bc and colemanite)as an-tioxidants have been investigated and compared to the effect of Al-Mg alloy,For CaO-MgO-C mate-rials,the effect of boron bearingadditives is better than Al-Mg alloy,The borate melt formed at high temperature would retard or prevent carbon oxidation,thus contributing to improved oxidation resistance,Preliminary investigations on the effect of boron bearing additives and Al-Mg alloy on corrosion resistance of doloma-carbon materials have indicated that simultaneous addition of the two types of additives would lead to pronounced improvement of slag corrosion resistance.
文摘The parameters influencing the process of carbon oxidation in magnesia-carbon refracto-ries are reviewed.A typology of their oxidation resistance measurements is then presented;four different method are discussed in details.No agreement has been reached yet on a standard-ized test method.So far,oxidation resistance describes a process more than a property.
文摘Water addition has direct impact on castables and needs to be under control placement and properties, In this work, two rheological properties, flow resistance and torque viscosity, have been measured against time, with different water addition in the same bauxile-based LC Castable mix. The flow resistance indicates the mobility, whereas the torque viscosity dictates the stability of a castable during installation. It has been observed that with 6.0wt% water addition, such a mix possesses good vibration castable characteristics; with 6.5 wt%, it shows good self-flow castable characteristics; and with 7.0 wt%, it can be a good pumpable castable, in every case with comparable mechanical properties. While with 7.5 wt% water addition, the properties of such castable are definitively impaired.
文摘In the present work, we used the technique of “low energy ion implantation + swift; heavy ion irradiation ”to investigate huge electronic excitations induced modification in N-doped graphite-like-carbon.
文摘In this work, the rheological behavior of ultra-low cement alumina-based castables with addition of flake graphite and extruded graphite pellets has been investigated by using IBB rheometer. Emphasis has been laid on the influence of the type and amount of carbon addition on rheological properties of the alumina-based castables and the results are compared with corresponding alumina castable samples without any carbon addition. It is found that alumina-based castables with extruded graphite pellets have good rheological behavior and flowability with lower water demand (<6.3%) and no segregation during the shearing of castable.
文摘The authors establish the existence of a large class of mathematical entropies (the so-called weak entropies) associated with the Euler equations for an isentropic, compressible fluid governed by a general pressure law. A mild assumption on the behavior of the pressure law near the vacuum is solely required. The analysis is based on an asymptotic expansion of the fundamental solution (called here the entropy kernel) of a highly singular Euler- Poisson-Darboux equation. The entropy kernel is only Holder continuous and its regularity is carefully inversti- gated. Relying on a notion introduced earlier by the authors, it is also proven that, for the Euler equations, the set of eatropy flux-splittings coincides with the set of entropies-entropy fluxes. There results imply the existence of a flux-splitting consistent with all of the entropy inequalities.
