The aim of this study is to enhance the value of local earth materials used in the construction of certain homes in the Republic of Guinea. Thus, a trial study to improve the quality of mud bricks using paper fibers o...The aim of this study is to enhance the value of local earth materials used in the construction of certain homes in the Republic of Guinea. Thus, a trial study to improve the quality of mud bricks using paper fibers obtained by grinding and soaking in water and then drying were used as a stabilizer in the manufacture of these mud bricks from the sample of two sites Dounkiwal (DK) (in Mamou and the sample from the urban commune of Kouroussa). To do this, certain methods and means of identification were carried out, namely: geotechnical, mineralogical and chemical analyses. Sample DK from Mamou has a silty-clay geotechnical characteristic with a plasticity index Ip of 12.75%. However, mineralogical and chemical studies showed that sample Dounkiwal (DK) (Mamou) contains a high proportion of silica and iron oxides (79.63%) and Fe2O3 (11.85%), associated with other alkaline earth oxides and ions: CaO;MgO;SO32−;Cl−, i.e. 3.96%;0.96%;0.28% and 0.039% respectively. Its loss on ignition (LOI) and insoluble residues are 15.40% and 56.36%. The evaluation of the number of huts in Upper and Middle Guinea showed that the populations of these areas have been using mud bricks for several decades in the construction of dwellings. The average value found for the compressive strength of these bricks (from samples I, II and III from Kouroussa) is 0.16 MPa. This value is appreciable in the construction of mud houses.展开更多
This study was part of the framework that contributed not only to the improvement of thermal comfort in housing but also to the decarbonization of the construction and building materials industry. For this purpose, te...This study was part of the framework that contributed not only to the improvement of thermal comfort in housing but also to the decarbonization of the construction and building materials industry. For this purpose, terracotta brick seems to meet these needs. Thus, the objective of this work was to evaluate the influence of the incorporation of coal fly ash from a thermal power plant on the physical and mechanical properties of fired bricks from grey clay in the Thicky area of Senegal. The coal fly ash was incorporated into the raw clay material in proportions of 0, 5, 10, and 15 % by weight. These two raw materials were first characterized by X-ray fluorescence spectroscopy (XRF). The XRF analyses showed that the most abundant oxides in clay were SiO2 (55.034%) and Fe2O3 (10.155%). In coal fly ash, SiO2 (38.574%) is predominant. The ash also contained Al2O3 (7.717%) and alicano-earthy melting oxides such as CaO (9.271%) and MgO (7.298%) etc. These melting oxides were necessary to facilitate the formation of the liquid phase when baking platelets. The latter, when burned at a temperature of 880°C, were characterized by determining the number of physico-mechanical parameters, such as linear shrinkage during cooking, water absorption, fire loss and compressive strength. A Hierarchical Ascending Classification of these different parameters was performed and three classes were obtained. Class 1 with better compressive strength (6.358 MPa), was in sample A (5%). Class 2 consisted of sample D (reference) and had a higher plasticity index (28.51%) and water absorption rate (11.19%). Finally, class 3, which included samples B (10%) and C (15%), had very high shrinkage and fire losses compared to other platelets. These results highlighted the possibility of using up to 5% of the coal fly ash in the production of new fired bricks with good performance.展开更多
This study aims to provide the basic knowledge for furnace refractory design by investigating refractory property changes occurred in a hydrogen atmosphere.Since refractory bricks are thermodynamically stable in a hyd...This study aims to provide the basic knowledge for furnace refractory design by investigating refractory property changes occurred in a hydrogen atmosphere.Since refractory bricks are thermodynamically stable in a hydrogen atmosphere at 1100°C,we tried to find out the minute changes.In this experiment,a refractory brick was prepared by andalusite,mullite chamotte,and clay as raw materials and heated to 1100°C in a 100%hydrogen atmosphere for 72 h.It was found that the strength of the brick was decreased and the color was changed to black by the reduction of impurities.And in addition,this study covered research on the slaking risk of MgO raw materials because the minimum temperature is expected to 400°C in fluidized reduction furnaces unlike shaft furnaces.展开更多
Conventional MgO-C bricks(graphite content>14 wt.%)produce a great deal of greenhouse gas emission,while low-carbon MgO-C bricks have serious thermal shock resistance during high-temperature service.To enhance the ...Conventional MgO-C bricks(graphite content>14 wt.%)produce a great deal of greenhouse gas emission,while low-carbon MgO-C bricks have serious thermal shock resistance during high-temperature service.To enhance the high-temperature mechanical property and thermal shock resistance of low-carbon MgO-C bricks,a novel route of introducing ZrSiO_(4) powder into low-carbon MgO-C bricks was reported in such refractories with 2 wt.% flaky graphite.The results indicate that the low-carbon MgO-C brick with 0.5 wt.%ZrSiO_(4) addition has the maximum hot modulus of rupture at 1400℃ and the corresponding specimen fired in the carbon embedded atmosphere has the maximum residual strength ratio(98.6%)after three thermal shock cycles.It is found that some needle-like AlON and plate-like Al_(2)O_(3)-ZrO_(2) composites were in situ formed in the matrices after the low-carbon MgO-C bricks were coked at 1400℃,which can enhance the high-temperature mechanical property and thermal shock resistance due to the effect of fiber toughening and particle toughening.Moreover,CO_(2) emission of the newly developed low-carbon MgO-C bricks is reduced by 58.3% per ton steel after using them as the working lining of a 90 t vacuum oxygen decarburization ladle.展开更多
The aim of this study was to evaluate the compressive strength of clay bricks and their stability to water absorption by inserting stabilizers such as lime and cement of 0%, 4%, 6%, 8%, 10%, 12% to 14%. Spectrometric ...The aim of this study was to evaluate the compressive strength of clay bricks and their stability to water absorption by inserting stabilizers such as lime and cement of 0%, 4%, 6%, 8%, 10%, 12% to 14%. Spectrometric analysis was used to characterize the various stabilizers and the clay used, and tests of resistance and water absorption were also carried out. The clay was found to be an aluminosilicate (15.55% to 17.17% Al2O3 and 42.12% to 44.15% SiO2). The lime contains 90.84% CaO and the cement has 17.80% SiO2, 3.46% Al2O3, 2.43% Fe2O3 and 58.47% CaO in the combined form of tricalcium silicate, dicalcium silicate, tricalcium aluminate and ferro-tetra calcium aluminate. The results showed that the insertion of locally available stabilizers (lime and cement) improved the strength of the material by almost 80% when the lime was increased from 0% to 14% for 14 days. For compressed cement, a 65% increase in strength was observed under the same conditions. Strength increases with drying time, with a 52% increase in strength at 28 days compared to 14 days. Furthermore, compressed cement bricks have a more compact structure, absorbing very little water (32%). In view of all these results, cement appears to be the best stabilizer, and compression improves compressive strength and reduces water absorption.展开更多
This study investigated the therapeutic effects on metabolic syndrome(MetS)and the impact on the intestinal barrier and gut microbiota of Fu brick tea aqueous extracts(FTE)on MetS in rats fed with a high-fat diet(HFD)...This study investigated the therapeutic effects on metabolic syndrome(MetS)and the impact on the intestinal barrier and gut microbiota of Fu brick tea aqueous extracts(FTE)on MetS in rats fed with a high-fat diet(HFD).Here,the results showed that FTE supplement significantly reduced HFD-induced weight gain,adiposity,dyslipidemia,fasting blood glucose(FBG)increment,and non-alcoholic fatty liver disease(NAFLD).Moreover,FTE supplement resulted in a decline in lipopolysaccharide(LPS)level and attenuation of colonic inflammation and oxidative stress to protect the intestinal barrier function.FTE supplement also maintained the intestinal barrier integrity by improving histological appearance and promoting ZO-1,Occludin,and Claudin-1 protein expression levels.Meanwhile,FTE supplement alleviated the gut microbiota dysbiosis by enhancing the Firmicutes/Bacteroidetes(F/B)ratio and stimulating the colonization of probiotic bacteria such as Akkermansia,Lactobacillus,Adlercreutzia,and Bacteroides.These findings collectively suggest that Fu brick tea could alleviate MetS and MetS-associated traits with the mechanism relevant to the protection of intestinal barrier and gut microbiota regulation.展开更多
With brick-wall solar greenhouses in Changli area as the research object,using temperature dynamic monitoring and statistical methods,the greenhouse structure suitable for promoting early cultivation of local peach tr...With brick-wall solar greenhouses in Changli area as the research object,using temperature dynamic monitoring and statistical methods,the greenhouse structure suitable for promoting early cultivation of local peach trees was selected by studying the temperature data of the solar greenhouses during the winter solstice,and a prediction model for daily average temperature was constructed.The results showed that greenhouse Ⅰ had reasonable structural parameters and good daylight during the day.However,due to the low wall thickness and poor insulation material,the minimum temperature was significantly lower than other greenhouses.The thermal insulation performance of greenhouse Ⅱ and Ⅲ was better than that of greenhouse Ⅰ,but the depth-span ratio and the front roof lighting angle were smaller.During the winter solstice,the average temperature of the three greenhouses was between 10 and 15℃,which was suitable for early cultivation of peach trees.The prediction model of daily average temperature was obtained:Daily average temperature=1.02+0.69×Daily average temperature of the previous day+0.02×Maximum temperature of the previous day-0.01×Minimum temperature of the previous day.To sum up,the structural parameters of brick-wall solar greenhouses suitable for early cultivation of peach trees in Changli area were as follows:span 6.5-8.5 m,depth-span ratio 0.47,front roof lighting angle 30°and wall thickness greater than 55 cm.展开更多
In order to improve the efficient and high-value recycling utilization rate of waste red bricks from construction waste,this study crushed and ground the waste red bricks to produce recycled brick powder(RBP)with diff...In order to improve the efficient and high-value recycling utilization rate of waste red bricks from construction waste,this study crushed and ground the waste red bricks to produce recycled brick powder(RBP)with different fineness,used the Andreasen model to explore the influence of RBP on the compact filling effect of cementitious material system based on the basic characteristics of RBP.The influence of grinding time(10,20,30 min)and content(0%,5%,10%,15%,20%)of RBP on the macroscopic mechanical properties of cementitious materials was investigated.We analyzed the significant impact of RBP particle characteristics on the compressive strength of the specimen with the aid of grey entropy theory,and revealed the influence mechanism of RBP on the microstructure of cementitious materials by scanning electron microscope(SEM)and nuclear magnetic resonance(NMR).The results show that the fineness of RBP after grinding is smaller than that of cement.The fineness of recycled brick powder increases gradually with the extension of grinding time,which is manifested as the increase of<3μm particles and the decrease of>18μm particles.Compared with the unitary cement cementitious material system,the particle gradation of the RBP-cement binary cementitious material system is closer to the closest packing state.With the increase of RBP content and grinding time,the compactness of the binary cementitious system gradually decreases,indicating that the incorporation of RBP reduces the mechanical strength of the specimen.The results of grey entropy show that the specific surface area D(0.1)and<45μm particles are the significant factors affecting the mechanical properties of cementitious materials mixed with RBP.RBP mainly affects the macroscopic properties of cementitious materials by affecting the internal compactness,the number of hydration products and the pore structure.The results of SEM show that when the RBP content is less than 15%,the content of C-S-H in cement paste increase,and the content of Ca(OH)2 decreases,and the content of C-S-H decreases and the content of Ca(OH)2 increases when the RBP content is more than 15%.The NMR results show that with the extension of grinding time,the pore size of micropore increases gradually,that of middle-small pores decreases gradually,and that of large pores remains unchanged.With the increase of RBP content,the micropores first decrease and then increase,and the middle-small pores and large pores gradually decrease.In summary,the compactness of cementitious material system can be improved by adjusting the fineness of RBP.Considering the performance of cementitious materials and the utilization rate of RBP,it is recommended that the grinding time of RBP is 20 min and the content is 10%-15%.展开更多
In order to study the effects of the contents of used mortar recycled aggregate(OMRA)and brick recycled aggregate(BRA)on the deformation properties of recycled aggregate concrete(RAC),under uniaxial compression condit...In order to study the effects of the contents of used mortar recycled aggregate(OMRA)and brick recycled aggregate(BRA)on the deformation properties of recycled aggregate concrete(RAC),under uniaxial compression conditions,The RAC of OMRA(0%,5%,10%,and 15%)and BRA(0%,3%,6%,9%,12%,and 15%)were studied.The experimental results show that,under uniaxial compression,the interfacial relationships of RAC containing OMRA and BRA between different materials are more complex,and the failure mechanism is also more complex.The content of OMRA and BRA had significant influence on the deformation behavior of RAC.When the content of OMRA and BRA is high,it is difficult for existing formulas and models to accurately represent the actual value.In this study,the influence of OMRA and BRA content is taken into account,and the existing formulas for calculating concrete deformation are modified,so that these formulas can more accurately calculate the elastic modulus,peak strain and ultimate strain of recycled concrete.The stress-strain formula of Guo concrete fits the stress-strain curve of concrete very well.We modified the formula on the basis of Guo formula to make the formula more suitable for the stress-strain curve of recycled concrete containing old mortar and brick,and the theoretical model proposed has better fitting accuracy.The study provides a valuable reference for nonlinear analysis of recycled aggregate concrete structures under different proportions of OMRA and BRA.展开更多
建立了由一个制造商和一个分销商组成的基于电子市场的二级供应链模型,讨论了分销商采用Bricks and Clicks模式分销产品,并在电子渠道进行季节后销售的情况,分析了供应链的契约协调问题及供应链成员的利润情况.研究发现改进的回购契约...建立了由一个制造商和一个分销商组成的基于电子市场的二级供应链模型,讨论了分销商采用Bricks and Clicks模式分销产品,并在电子渠道进行季节后销售的情况,分析了供应链的契约协调问题及供应链成员的利润情况.研究发现改进的回购契约可以使Bricks and Clicks分销模式下基于电子市场的二级供应链模型达到协调,使分销商的订货量达到供应链最优,并且使供应链成员的利润达到Pareto改进,达到"双赢".最后,通过算例验证了结论.展开更多
The influence of V2O3, FeO, TiO2, MnO and MgO in vanadium slag on the corrosion mechanism of MgO-C bricks was studied by stationary immersion tests at vanadium-extracting temperature. Experimental results show that Fe...The influence of V2O3, FeO, TiO2, MnO and MgO in vanadium slag on the corrosion mechanism of MgO-C bricks was studied by stationary immersion tests at vanadium-extracting temperature. Experimental results show that FeO, TiO2, and MnO could enhance the corrosion rate and V2O3 and MgO could decrease it. Microstructure and phase composition of worn samples were investigated by SEM-EDS, revealing the presence of Fe particles, produced by graphite reduction, and (Mg,Fe,Mn)O solid solution at the interface. The formation process of (Mg,Fe,Mn)O solid solution was discussed and the corrosion mechnism of MgO-C bricks was thus proposed.展开更多
Low-dimensional nanomaterials such as graphene can be used as a reinforcing agent in building materials to enhance the strength and durability. Common building materials burnt red soil bricks and fly ash bricks were r...Low-dimensional nanomaterials such as graphene can be used as a reinforcing agent in building materials to enhance the strength and durability. Common building materials burnt red soil bricks and fly ash bricks were reinforced with various amounts of graphene, and the effect of graphene on the strength of these newly developed nanocomposites was studied. The fly ash brick nanocomposite samples were cured as per their standard curing time, and the burnt red soil brick nanocomposite samples were merely dried in the sun instead of being subjected to the traditional heat treatment for days to achieve sufficient strength. The water absorption ability of the fly ash bricks was also discussed. The compressive strength of all of the graphene-reinforced nanocomposite samples was tested, along with that of some standard (without graphene) composite samples with the same dimensions, to evaluate the effects of the addition of various amounts of graphene on the compressive strength of the bricks.展开更多
Currently the service life of CDQ shafts in China is mainly restricted by the properties of the inclined flue bricks.In this work,based on the systematic analysis of the damage mechanism of inclined flue refractories,...Currently the service life of CDQ shafts in China is mainly restricted by the properties of the inclined flue bricks.In this work,based on the systematic analysis of the damage mechanism of inclined flue refractories,high performance mullite-SiC bricks were developed.The bricks were produced by corundum,andalusite,SiC and other high purity raw materials.Metal silicon and alumina ultra micropowder were added to form dispersion multi-phase structure,fortifying the matrix and improving the microstructure.The products have excellent properties such as low porosity,high density,good wear resistance,high refractoriness under load,and good thermal shock resistance.The products can replace the ordinary mullite-SiC bricks and obtain a good service life.展开更多
Serving as recycled coarse aggregate,the pretreated rural building waste was added into the concrete hollow bricks in the varying replacement of 0,20%,40%,60%,80% and 100%.By testing its compressive strength,flexural ...Serving as recycled coarse aggregate,the pretreated rural building waste was added into the concrete hollow bricks in the varying replacement of 0,20%,40%,60%,80% and 100%.By testing its compressive strength,flexural strength,mass and strength loss after freeze-thaw cycles,the impact of the different replacement on mechanical and frost-resistance properties of concrete hollow bricks was presented through SEM analysis.The experimental results show that,with the increase in recycled coarse aggregate replacement rate,the mechanical and frost-resistance properties show a downward trend;when the replacement rate is 40%,28 d compressive strength and flexural strength of concrete hollow brick demonstrate the good peak value which meet the requirement of the national standard for ordinary small concrete hollow bricks;the interfacial structures of the pretreated recycled concrete is more complicated than those of concrete made of natural aggregate,but the former enjoys better interface bonding and tight structure.展开更多
Conversion-type fluoride cathode can provide considerable energy density for Li batteries,however its scalable and facile synthesis strategies are still lacking.Here,a novel Fe-based deep eutectic solvent composed of ...Conversion-type fluoride cathode can provide considerable energy density for Li batteries,however its scalable and facile synthesis strategies are still lacking.Here,a novel Fe-based deep eutectic solvent composed of nitrite and methylsulfonylmethane is proposed as both the reaction medium and precursor to synthesize O-doped FeF3porous bricks.This method is cheaper,safe,mildly operable,environmentally friendly and recyclable for non-fluorinated metal cations.The homogenization of charge and mass transport in cathode network effectively mitigates the volume extrusion and electrode coarsening even for the micro-sized monolithic particles.The Co-solvation modulated fluoride cathode delivers high reversible capacity in a wide temperature range(486 and 235 mA h g^(-1)at 25℃ and-20℃ respectively),excellent rate performance(312 mA h g^(-1)at 1000 mA g^(-1)),corresponding to an energy density as high as672.1 W h kg^(-1)under a power density of 2154.3 W kg^(-1).The successful operation of fluoride pouchcell with a capacity exceeding 450 mA h g^(-1)(even under thin Li foil and lean electrolyte conditions) indicates its potentiality of commercial application.展开更多
Corrosion effect of ladle furnace （LF） refining slag on fired MgO-CaO bricks with about 34% CaO was studied by static crucible method,and corrosion mechanism was analyzed by techniques of scan electron micrograph,en...Corrosion effect of ladle furnace （LF） refining slag on fired MgO-CaO bricks with about 34% CaO was studied by static crucible method,and corrosion mechanism was analyzed by techniques of scan electron micrograph,energy dispersive spectrometer,and X-ray diffraction. The results show that：MgO-CaO bricks exhibit excellent corrosion resistance but poor penetration resistance to LF refining slag; oxidation of （Mg·Fe）O in reaction zone results in volume expansion forming cracks; penetration of 2CaO·Fe2O3 （C2F） from slag to MgO-CaO bricks increases liquid phases which accelerates corrosion of the bricks; a protective layer of 2CaO·SiO2 formed on reaction interface prevents penetration of C2F to the bricks.展开更多
In order to utilize solid wastes,ceramic simple bricks with high performances were made from industrial solid wastes such as red mud,fly ash and poor clay shale as main raw materials in this paper.The phase compositio...In order to utilize solid wastes,ceramic simple bricks with high performances were made from industrial solid wastes such as red mud,fly ash and poor clay shale as main raw materials in this paper.The phase compositions and microstructures were tested by XRD,SEM and EPMA.The experimental results show that the water absorption is 45.64%,the porosity is 58.91%,bulk density is 1.29 g·cm-3,compressive strength is 54.91 MPa,bending strength is 29.52 MPa,freeze-thaw resistance is 29.28 MPa,specific heat capacity at constant pressure is 1.31 J·g-1·K-1,thermal diffusivity is 5.89×10-3 cm2·s-1,and thermal conductivity is 1.15×10-2 W·cm-1·K-1.These effects of additives and preparation process to the properties and microstructures were discussed in detail.The reaction mechanism was also discussed.The results of the reaction mechanism show that there has wollastonite and feldspar generated during the process of firing while Ca gathered around the feldspar,and then Ca would displace K and generated cacoclasite.展开更多
The annual output of China ' s silica brick amounts up to over 300 thousand tons, which accounts for more than 10% of the total output of silica bricks in the world. Besides satisfying domestic markets , China s s...The annual output of China ' s silica brick amounts up to over 300 thousand tons, which accounts for more than 10% of the total output of silica bricks in the world. Besides satisfying domestic markets , China s silica bricks have been exported to many countries and regions such as Japan, USA etc. In this paper, the situation of silica bricks production, technology, sales and exporting have been described. Also suggestions on improvement of silica bricks quality and exporting, corporation with foreign partners have been put forward in order to win larger market share both at home and abroad.展开更多
文摘The aim of this study is to enhance the value of local earth materials used in the construction of certain homes in the Republic of Guinea. Thus, a trial study to improve the quality of mud bricks using paper fibers obtained by grinding and soaking in water and then drying were used as a stabilizer in the manufacture of these mud bricks from the sample of two sites Dounkiwal (DK) (in Mamou and the sample from the urban commune of Kouroussa). To do this, certain methods and means of identification were carried out, namely: geotechnical, mineralogical and chemical analyses. Sample DK from Mamou has a silty-clay geotechnical characteristic with a plasticity index Ip of 12.75%. However, mineralogical and chemical studies showed that sample Dounkiwal (DK) (Mamou) contains a high proportion of silica and iron oxides (79.63%) and Fe2O3 (11.85%), associated with other alkaline earth oxides and ions: CaO;MgO;SO32−;Cl−, i.e. 3.96%;0.96%;0.28% and 0.039% respectively. Its loss on ignition (LOI) and insoluble residues are 15.40% and 56.36%. The evaluation of the number of huts in Upper and Middle Guinea showed that the populations of these areas have been using mud bricks for several decades in the construction of dwellings. The average value found for the compressive strength of these bricks (from samples I, II and III from Kouroussa) is 0.16 MPa. This value is appreciable in the construction of mud houses.
文摘This study was part of the framework that contributed not only to the improvement of thermal comfort in housing but also to the decarbonization of the construction and building materials industry. For this purpose, terracotta brick seems to meet these needs. Thus, the objective of this work was to evaluate the influence of the incorporation of coal fly ash from a thermal power plant on the physical and mechanical properties of fired bricks from grey clay in the Thicky area of Senegal. The coal fly ash was incorporated into the raw clay material in proportions of 0, 5, 10, and 15 % by weight. These two raw materials were first characterized by X-ray fluorescence spectroscopy (XRF). The XRF analyses showed that the most abundant oxides in clay were SiO2 (55.034%) and Fe2O3 (10.155%). In coal fly ash, SiO2 (38.574%) is predominant. The ash also contained Al2O3 (7.717%) and alicano-earthy melting oxides such as CaO (9.271%) and MgO (7.298%) etc. These melting oxides were necessary to facilitate the formation of the liquid phase when baking platelets. The latter, when burned at a temperature of 880°C, were characterized by determining the number of physico-mechanical parameters, such as linear shrinkage during cooking, water absorption, fire loss and compressive strength. A Hierarchical Ascending Classification of these different parameters was performed and three classes were obtained. Class 1 with better compressive strength (6.358 MPa), was in sample A (5%). Class 2 consisted of sample D (reference) and had a higher plasticity index (28.51%) and water absorption rate (11.19%). Finally, class 3, which included samples B (10%) and C (15%), had very high shrinkage and fire losses compared to other platelets. These results highlighted the possibility of using up to 5% of the coal fly ash in the production of new fired bricks with good performance.
基金supported by the Korea Planning & Evaluation Institute of Industrial Technology (KEIT)the Ministry of Trade, Industry & Energy (MOTIE, Korea) of the Republic of Korea (No. RS2023-00262421)
文摘This study aims to provide the basic knowledge for furnace refractory design by investigating refractory property changes occurred in a hydrogen atmosphere.Since refractory bricks are thermodynamically stable in a hydrogen atmosphere at 1100°C,we tried to find out the minute changes.In this experiment,a refractory brick was prepared by andalusite,mullite chamotte,and clay as raw materials and heated to 1100°C in a 100%hydrogen atmosphere for 72 h.It was found that the strength of the brick was decreased and the color was changed to black by the reduction of impurities.And in addition,this study covered research on the slaking risk of MgO raw materials because the minimum temperature is expected to 400°C in fluidized reduction furnaces unlike shaft furnaces.
基金Enterprise Research and Development Project of Beijing Lirr High-Temperature Materials Co.,Ltd.(2020-02)Key Scientific Research Project for Universities and Colleges in Henan Province(19A430028)+1 种基金the Excellent Youth Research Project of Anhui Province(2022AH030135)the PhD Research Funding of Suzhou University(2021BSK041).
文摘Conventional MgO-C bricks(graphite content>14 wt.%)produce a great deal of greenhouse gas emission,while low-carbon MgO-C bricks have serious thermal shock resistance during high-temperature service.To enhance the high-temperature mechanical property and thermal shock resistance of low-carbon MgO-C bricks,a novel route of introducing ZrSiO_(4) powder into low-carbon MgO-C bricks was reported in such refractories with 2 wt.% flaky graphite.The results indicate that the low-carbon MgO-C brick with 0.5 wt.%ZrSiO_(4) addition has the maximum hot modulus of rupture at 1400℃ and the corresponding specimen fired in the carbon embedded atmosphere has the maximum residual strength ratio(98.6%)after three thermal shock cycles.It is found that some needle-like AlON and plate-like Al_(2)O_(3)-ZrO_(2) composites were in situ formed in the matrices after the low-carbon MgO-C bricks were coked at 1400℃,which can enhance the high-temperature mechanical property and thermal shock resistance due to the effect of fiber toughening and particle toughening.Moreover,CO_(2) emission of the newly developed low-carbon MgO-C bricks is reduced by 58.3% per ton steel after using them as the working lining of a 90 t vacuum oxygen decarburization ladle.
文摘The aim of this study was to evaluate the compressive strength of clay bricks and their stability to water absorption by inserting stabilizers such as lime and cement of 0%, 4%, 6%, 8%, 10%, 12% to 14%. Spectrometric analysis was used to characterize the various stabilizers and the clay used, and tests of resistance and water absorption were also carried out. The clay was found to be an aluminosilicate (15.55% to 17.17% Al2O3 and 42.12% to 44.15% SiO2). The lime contains 90.84% CaO and the cement has 17.80% SiO2, 3.46% Al2O3, 2.43% Fe2O3 and 58.47% CaO in the combined form of tricalcium silicate, dicalcium silicate, tricalcium aluminate and ferro-tetra calcium aluminate. The results showed that the insertion of locally available stabilizers (lime and cement) improved the strength of the material by almost 80% when the lime was increased from 0% to 14% for 14 days. For compressed cement, a 65% increase in strength was observed under the same conditions. Strength increases with drying time, with a 52% increase in strength at 28 days compared to 14 days. Furthermore, compressed cement bricks have a more compact structure, absorbing very little water (32%). In view of all these results, cement appears to be the best stabilizer, and compression improves compressive strength and reduces water absorption.
基金supported by the Earmarked Fund for the Modern Agricultural Industry Technology System(CARS19),Research on Quality Chemical Characteristics and Healthy Function of Xianyang Brick Tea(2021kjc-js231)Research on Metabolite Alteration and Mechanism in Fu Brick Tea under the Action of Eurotium cristatum(31471706).
文摘This study investigated the therapeutic effects on metabolic syndrome(MetS)and the impact on the intestinal barrier and gut microbiota of Fu brick tea aqueous extracts(FTE)on MetS in rats fed with a high-fat diet(HFD).Here,the results showed that FTE supplement significantly reduced HFD-induced weight gain,adiposity,dyslipidemia,fasting blood glucose(FBG)increment,and non-alcoholic fatty liver disease(NAFLD).Moreover,FTE supplement resulted in a decline in lipopolysaccharide(LPS)level and attenuation of colonic inflammation and oxidative stress to protect the intestinal barrier function.FTE supplement also maintained the intestinal barrier integrity by improving histological appearance and promoting ZO-1,Occludin,and Claudin-1 protein expression levels.Meanwhile,FTE supplement alleviated the gut microbiota dysbiosis by enhancing the Firmicutes/Bacteroidetes(F/B)ratio and stimulating the colonization of probiotic bacteria such as Akkermansia,Lactobacillus,Adlercreutzia,and Bacteroides.These findings collectively suggest that Fu brick tea could alleviate MetS and MetS-associated traits with the mechanism relevant to the protection of intestinal barrier and gut microbiota regulation.
基金Supported by Modern Agricultural Industry Technology System Innovation Team Construction in Hebei Province(HBCT2023130404).
文摘With brick-wall solar greenhouses in Changli area as the research object,using temperature dynamic monitoring and statistical methods,the greenhouse structure suitable for promoting early cultivation of local peach trees was selected by studying the temperature data of the solar greenhouses during the winter solstice,and a prediction model for daily average temperature was constructed.The results showed that greenhouse Ⅰ had reasonable structural parameters and good daylight during the day.However,due to the low wall thickness and poor insulation material,the minimum temperature was significantly lower than other greenhouses.The thermal insulation performance of greenhouse Ⅱ and Ⅲ was better than that of greenhouse Ⅰ,but the depth-span ratio and the front roof lighting angle were smaller.During the winter solstice,the average temperature of the three greenhouses was between 10 and 15℃,which was suitable for early cultivation of peach trees.The prediction model of daily average temperature was obtained:Daily average temperature=1.02+0.69×Daily average temperature of the previous day+0.02×Maximum temperature of the previous day-0.01×Minimum temperature of the previous day.To sum up,the structural parameters of brick-wall solar greenhouses suitable for early cultivation of peach trees in Changli area were as follows:span 6.5-8.5 m,depth-span ratio 0.47,front roof lighting angle 30°and wall thickness greater than 55 cm.
基金Funded by National Natural Science Foundation of China(No.52108219)Lanzhou University of Technology Hongliu Outstanding Young Talent Program,China(No.062407)The High Quality of Green Machine-made Aggregate and the Evolution Mechanism of Concrete Life Cycle Performance in the Harsh Environment of Northwest China(No.U21A20150)。
文摘In order to improve the efficient and high-value recycling utilization rate of waste red bricks from construction waste,this study crushed and ground the waste red bricks to produce recycled brick powder(RBP)with different fineness,used the Andreasen model to explore the influence of RBP on the compact filling effect of cementitious material system based on the basic characteristics of RBP.The influence of grinding time(10,20,30 min)and content(0%,5%,10%,15%,20%)of RBP on the macroscopic mechanical properties of cementitious materials was investigated.We analyzed the significant impact of RBP particle characteristics on the compressive strength of the specimen with the aid of grey entropy theory,and revealed the influence mechanism of RBP on the microstructure of cementitious materials by scanning electron microscope(SEM)and nuclear magnetic resonance(NMR).The results show that the fineness of RBP after grinding is smaller than that of cement.The fineness of recycled brick powder increases gradually with the extension of grinding time,which is manifested as the increase of<3μm particles and the decrease of>18μm particles.Compared with the unitary cement cementitious material system,the particle gradation of the RBP-cement binary cementitious material system is closer to the closest packing state.With the increase of RBP content and grinding time,the compactness of the binary cementitious system gradually decreases,indicating that the incorporation of RBP reduces the mechanical strength of the specimen.The results of grey entropy show that the specific surface area D(0.1)and<45μm particles are the significant factors affecting the mechanical properties of cementitious materials mixed with RBP.RBP mainly affects the macroscopic properties of cementitious materials by affecting the internal compactness,the number of hydration products and the pore structure.The results of SEM show that when the RBP content is less than 15%,the content of C-S-H in cement paste increase,and the content of Ca(OH)2 decreases,and the content of C-S-H decreases and the content of Ca(OH)2 increases when the RBP content is more than 15%.The NMR results show that with the extension of grinding time,the pore size of micropore increases gradually,that of middle-small pores decreases gradually,and that of large pores remains unchanged.With the increase of RBP content,the micropores first decrease and then increase,and the middle-small pores and large pores gradually decrease.In summary,the compactness of cementitious material system can be improved by adjusting the fineness of RBP.Considering the performance of cementitious materials and the utilization rate of RBP,it is recommended that the grinding time of RBP is 20 min and the content is 10%-15%.
基金Funded by the Project of National Key Research and Development Program of China(No.2019YFC1906202)。
文摘In order to study the effects of the contents of used mortar recycled aggregate(OMRA)and brick recycled aggregate(BRA)on the deformation properties of recycled aggregate concrete(RAC),under uniaxial compression conditions,The RAC of OMRA(0%,5%,10%,and 15%)and BRA(0%,3%,6%,9%,12%,and 15%)were studied.The experimental results show that,under uniaxial compression,the interfacial relationships of RAC containing OMRA and BRA between different materials are more complex,and the failure mechanism is also more complex.The content of OMRA and BRA had significant influence on the deformation behavior of RAC.When the content of OMRA and BRA is high,it is difficult for existing formulas and models to accurately represent the actual value.In this study,the influence of OMRA and BRA content is taken into account,and the existing formulas for calculating concrete deformation are modified,so that these formulas can more accurately calculate the elastic modulus,peak strain and ultimate strain of recycled concrete.The stress-strain formula of Guo concrete fits the stress-strain curve of concrete very well.We modified the formula on the basis of Guo formula to make the formula more suitable for the stress-strain curve of recycled concrete containing old mortar and brick,and the theoretical model proposed has better fitting accuracy.The study provides a valuable reference for nonlinear analysis of recycled aggregate concrete structures under different proportions of OMRA and BRA.
文摘建立了由一个制造商和一个分销商组成的基于电子市场的二级供应链模型,讨论了分销商采用Bricks and Clicks模式分销产品,并在电子渠道进行季节后销售的情况,分析了供应链的契约协调问题及供应链成员的利润情况.研究发现改进的回购契约可以使Bricks and Clicks分销模式下基于电子市场的二级供应链模型达到协调,使分销商的订货量达到供应链最优,并且使供应链成员的利润达到Pareto改进,达到"双赢".最后,通过算例验证了结论.
基金Item Sponsored by National Natural Science Foundation of China (51090382)
文摘The influence of V2O3, FeO, TiO2, MnO and MgO in vanadium slag on the corrosion mechanism of MgO-C bricks was studied by stationary immersion tests at vanadium-extracting temperature. Experimental results show that FeO, TiO2, and MnO could enhance the corrosion rate and V2O3 and MgO could decrease it. Microstructure and phase composition of worn samples were investigated by SEM-EDS, revealing the presence of Fe particles, produced by graphite reduction, and (Mg,Fe,Mn)O solid solution at the interface. The formation process of (Mg,Fe,Mn)O solid solution was discussed and the corrosion mechnism of MgO-C bricks was thus proposed.
文摘Low-dimensional nanomaterials such as graphene can be used as a reinforcing agent in building materials to enhance the strength and durability. Common building materials burnt red soil bricks and fly ash bricks were reinforced with various amounts of graphene, and the effect of graphene on the strength of these newly developed nanocomposites was studied. The fly ash brick nanocomposite samples were cured as per their standard curing time, and the burnt red soil brick nanocomposite samples were merely dried in the sun instead of being subjected to the traditional heat treatment for days to achieve sufficient strength. The water absorption ability of the fly ash bricks was also discussed. The compressive strength of all of the graphene-reinforced nanocomposite samples was tested, along with that of some standard (without graphene) composite samples with the same dimensions, to evaluate the effects of the addition of various amounts of graphene on the compressive strength of the bricks.
文摘Currently the service life of CDQ shafts in China is mainly restricted by the properties of the inclined flue bricks.In this work,based on the systematic analysis of the damage mechanism of inclined flue refractories,high performance mullite-SiC bricks were developed.The bricks were produced by corundum,andalusite,SiC and other high purity raw materials.Metal silicon and alumina ultra micropowder were added to form dispersion multi-phase structure,fortifying the matrix and improving the microstructure.The products have excellent properties such as low porosity,high density,good wear resistance,high refractoriness under load,and good thermal shock resistance.The products can replace the ordinary mullite-SiC bricks and obtain a good service life.
基金Funded by the National Key Technology R&D Program of China for the 11th Five-Year Plan(2006BAJ04A04)the 100 Million Human Resources Foundation of Liaoning Province (2008921034)the Human Resource Development in Shenyang Special Foundation (2008140403011)
文摘Serving as recycled coarse aggregate,the pretreated rural building waste was added into the concrete hollow bricks in the varying replacement of 0,20%,40%,60%,80% and 100%.By testing its compressive strength,flexural strength,mass and strength loss after freeze-thaw cycles,the impact of the different replacement on mechanical and frost-resistance properties of concrete hollow bricks was presented through SEM analysis.The experimental results show that,with the increase in recycled coarse aggregate replacement rate,the mechanical and frost-resistance properties show a downward trend;when the replacement rate is 40%,28 d compressive strength and flexural strength of concrete hollow brick demonstrate the good peak value which meet the requirement of the national standard for ordinary small concrete hollow bricks;the interfacial structures of the pretreated recycled concrete is more complicated than those of concrete made of natural aggregate,but the former enjoys better interface bonding and tight structure.
基金supported by the National Natural Science Foundation of China(51772313,21975276 and 52102329)the Shanghai Science and Technology Committee(20520710800)support by the Program of Shanghai Academic Research Leader(21XD1424400)。
文摘Conversion-type fluoride cathode can provide considerable energy density for Li batteries,however its scalable and facile synthesis strategies are still lacking.Here,a novel Fe-based deep eutectic solvent composed of nitrite and methylsulfonylmethane is proposed as both the reaction medium and precursor to synthesize O-doped FeF3porous bricks.This method is cheaper,safe,mildly operable,environmentally friendly and recyclable for non-fluorinated metal cations.The homogenization of charge and mass transport in cathode network effectively mitigates the volume extrusion and electrode coarsening even for the micro-sized monolithic particles.The Co-solvation modulated fluoride cathode delivers high reversible capacity in a wide temperature range(486 and 235 mA h g^(-1)at 25℃ and-20℃ respectively),excellent rate performance(312 mA h g^(-1)at 1000 mA g^(-1)),corresponding to an energy density as high as672.1 W h kg^(-1)under a power density of 2154.3 W kg^(-1).The successful operation of fluoride pouchcell with a capacity exceeding 450 mA h g^(-1)(even under thin Li foil and lean electrolyte conditions) indicates its potentiality of commercial application.
文摘Corrosion effect of ladle furnace （LF） refining slag on fired MgO-CaO bricks with about 34% CaO was studied by static crucible method,and corrosion mechanism was analyzed by techniques of scan electron micrograph,energy dispersive spectrometer,and X-ray diffraction. The results show that：MgO-CaO bricks exhibit excellent corrosion resistance but poor penetration resistance to LF refining slag; oxidation of （Mg·Fe）O in reaction zone results in volume expansion forming cracks; penetration of 2CaO·Fe2O3 （C2F） from slag to MgO-CaO bricks increases liquid phases which accelerates corrosion of the bricks; a protective layer of 2CaO·SiO2 formed on reaction interface prevents penetration of C2F to the bricks.
基金Funded by the 11th Five-Year National Key Technology R&D Program(2008BAC41B00)
文摘In order to utilize solid wastes,ceramic simple bricks with high performances were made from industrial solid wastes such as red mud,fly ash and poor clay shale as main raw materials in this paper.The phase compositions and microstructures were tested by XRD,SEM and EPMA.The experimental results show that the water absorption is 45.64%,the porosity is 58.91%,bulk density is 1.29 g·cm-3,compressive strength is 54.91 MPa,bending strength is 29.52 MPa,freeze-thaw resistance is 29.28 MPa,specific heat capacity at constant pressure is 1.31 J·g-1·K-1,thermal diffusivity is 5.89×10-3 cm2·s-1,and thermal conductivity is 1.15×10-2 W·cm-1·K-1.These effects of additives and preparation process to the properties and microstructures were discussed in detail.The reaction mechanism was also discussed.The results of the reaction mechanism show that there has wollastonite and feldspar generated during the process of firing while Ca gathered around the feldspar,and then Ca would displace K and generated cacoclasite.
文摘The annual output of China ' s silica brick amounts up to over 300 thousand tons, which accounts for more than 10% of the total output of silica bricks in the world. Besides satisfying domestic markets , China s silica bricks have been exported to many countries and regions such as Japan, USA etc. In this paper, the situation of silica bricks production, technology, sales and exporting have been described. Also suggestions on improvement of silica bricks quality and exporting, corporation with foreign partners have been put forward in order to win larger market share both at home and abroad.
