As a heat-resistant wave-absorbing material,silicon carbide(SiC)aerogel has become a research hotspot at present.However,the most common silicon sources are organosilanes,which are costly and toxic.In this work,SiC ae...As a heat-resistant wave-absorbing material,silicon carbide(SiC)aerogel has become a research hotspot at present.However,the most common silicon sources are organosilanes,which are costly and toxic.In this work,SiC aerogels were successfully prepared by using water glass as the silicon source.Specifically,the microstructure and chemical composition of SiC aerogels were controlled by adjusting the Si to C molar ratio during the sol–gel process,and the effect on SiC aerogel microwave absorption properties was investigated.The SiC aerogels prepared with Si:C molar ratio of 1:1 have an effective electromagnetic wave absorption capacity,with a minimum reflection loss value of-46.30 dB at 12.88 GHz and an effective frequency bandwidth of 4.02 GHz.They also have good physical properties,such as the density of0.0444 g/cm^(3),the thermal conductivity of 0.0621 W/(m·K),and the specific surface area of 1099 m^(2)/g.These lightweight composites with microwave-absorbing properties and low thermal conductivity can be used as thermal protection materials for space shuttles and reusable carriers.展开更多
This paper concentrates on the development of glasses with self-cleaning surfaces exhibiting high water contact angles. In this study, we prepared super-hydrophobic nano-ceramic coated glass based on titania & sil...This paper concentrates on the development of glasses with self-cleaning surfaces exhibiting high water contact angles. In this study, we prepared super-hydrophobic nano-ceramic coated glass based on titania & silica using simple sol-gel & dip coating methods and studied the best composition of the coatings by altering ratios of titanium tetraisopropoxide (TTIP)/tetraethyl orthosilicate (TEOS) with different homogenizing agents. We characterized the coatings by surface roughness measurement, percentage of optical transmission, static contact angle, near-infrared (NIR) transmission, and diffuse reflectance. The fabrication of coatings on glass substrates played an important role in increasing the water contact angle of about 95° and visible & NIR transmission of about 90%. We compared our modified glass substrate with commercial low emissivity (Low E) glass using X-ray diffraction (XRD) analysis, which showed pure amorphous surface claiming excellent wettability and thus the prepared glass substrate could have a variety of applications in different fields.展开更多
By using a downward penetration testing device, a large number of experiments were made to investigate the effects of surfactants (sodium succinate, sodium dodecyl sulfonate and dodecyl benzene sulfonic acid sodium sa...By using a downward penetration testing device, a large number of experiments were made to investigate the effects of surfactants (sodium succinate, sodium dodecyl sulfonate and dodecyl benzene sulfonic acid sodium salt) on the penetration ability of the calcium chloride and water glass solutions in four dust samples. The experimental results showed that the surfactants can enhance the penetration ability and decrease the surface tension of the calcium chloride and water glass solutions in great extent. After adding the surfactants in 0.2—0.6 wt.% to the solutions of calcium chloride and water glass in 5—25 wt.% respectively, the largest percent of penetration ability increases to 28% more. Among the three surfactants, the size of their effects on the penetration ability of calcium chloride and water solutions in the dust samples is dodecyl benzene sulfonic acid sodium salt, sodium dodecyl sulfonate and sodium succinate.The achieved conclusions are great significant for calcium chloride and water glass to be applied in the field of soil stabilization and raising dust control.展开更多
Bulk metallic glass rings have the potential applications as annular gasket and active solder in special fields. The bulk metallic glass ring of ZГ41.2Ti13.8Cu12.5Ni10.0Be22.5 with the outer diameter, the inner diame...Bulk metallic glass rings have the potential applications as annular gasket and active solder in special fields. The bulk metallic glass ring of ZГ41.2Ti13.8Cu12.5Ni10.0Be22.5 with the outer diameter, the inner diameter, and the thickness of 38, 36, and 5 mm, respectively, was prepared by using a special shaped quartz tube water quenching method. The mechanical properties along the whole cross section were investigated by a nanoindentation method, and no evident variation of the Young's modulus and hardness was found, further indicating the single amorphous structure. Amorphous ring and tube-shape parts with different dimensions can be produced by this method.展开更多
Wet reclamation of waste sodium silicate-bonded sand produces much alkaline sewage and causes pollution. Recycling water glass from wet reclamation sewage of the waste sodium silicate-bonded sand can solve pollution i...Wet reclamation of waste sodium silicate-bonded sand produces much alkaline sewage and causes pollution. Recycling water glass from wet reclamation sewage of the waste sodium silicate-bonded sand can solve pollution issues and generate economic benefits. In this work, the wet reclamation sewage was filtered, and the filtrate was causticized with a quicklime powder to produce a lye. The effects of causticization temperature, causticization time, and the amount of quicklime powder on the causticization rate were studied. The lye was used to dissolve the silica in the filtration residue to prepare a sodium silicate solution. The effects of the mass of filtration residue, dissolution temperature, and dissolution time on sodium silicate modulus were studied. Finally, the recycled water glass was obtained by concentrating the sodium silicate solution, and the bonding strength of the recycled water glass was tested. The results showed that the causticization rate could be improved by increasing the amount of quicklime powder, causticization temperature, and causticization time, and the highest causticization rate was above 92%. Amorphous silica in the filtration residue dissolved in the lye. Increasing the amount of the filtration residue, dissolution temperature, and dissolution time could improve the sodium silicate modulus. The bonding strength of the recycled water glass was close to that of commercial water glass. The recycled water glass could be used as a substitute for the commercial water glass.展开更多
The rheological behavior of phosphoric acid-water glass grout in different mixing ratios was studied. Grout made of water glass with Baume degree of 20° and 13.4% phosphoric acid by 1:1 volume ratio is found to b...The rheological behavior of phosphoric acid-water glass grout in different mixing ratios was studied. Grout made of water glass with Baume degree of 20° and 13.4% phosphoric acid by 1:1 volume ratio is found to be more effective in stopping water. Laboratory model test of water shutoff by grouting was conducted. Test results show that the diffusion length and water cutoff effect of the grout are significantly improved as the grout head is raised, due to the dilution of underground water, and it takes the grout longer than its gel time to cut off water.展开更多
The paper presents the research results of using an innovative method to reclaim the waste moulding sands containing water glass. Two of the examined processes are connected with "dry" or "wet" act...The paper presents the research results of using an innovative method to reclaim the waste moulding sands containing water glass. Two of the examined processes are connected with "dry" or "wet" activation of inorganic binder in waste moulding sand mixtures physically hardened by microwave radiation. The sand mixtures consisting of high-silica sand and water-glass with average molar module 2.5, were subjected to the following cyclical process: mixing the components, compacting, microwave heating, cooling-down, thermally loading the mould to 800 °C, cooling-down to ambient temperature, and knocking-out. After being knocked-out, the waste moulding sands were subjected to either dry or wet activation of the binder. To activate thermally treated inorganic binder, each of the examined processes employed the surface phenomenon usually associated to mechanical reclamation. The study also covered possible use of some elements of wet reclamation to rehydrate waste binder. To evaluate the effectiveness of the two proposed methods of waste binder activation, selected strength and technological parameters were measured. After each subsequent processing cycle, the permeability, tensile strength and bending strength were determined. In addition, the surface of activated sand grains was examined with a scanning electron microscope. Analysis of the results indicates that it is possible to re-activate the used binder such as sodium silicate, and to stabilize the strength parameters in both activation processes. Permeability of the refreshed moulding sands strongly depends on the surface condition of high-silica grains. The wet activation process by wetting and buffering knocked-out moulding sands in closed humid environment makes it possible to reduce the content of refreshing additive in water-glass. The moulding sands cyclically prepared in both processes do not require the addition of fresh high-silica sand. The relatively high quality achieved in the refreshed moulding sands allows them to be reused for manufacture of next moulds. Thus, the two proposed methods for cyclically processing used moulding sands containing sodium silicate, subject to microwave hardening, are suitable for economic and ecological circulation moulding mixtures.展开更多
Production of glass-ceramics by sintering the molten slag obtained from electric arc furnace treatment of fly ash was investigated. The effect of washing pretreatment prior to melting the fly ash on the microstructure...Production of glass-ceramics by sintering the molten slag obtained from electric arc furnace treatment of fly ash was investigated. The effect of washing pretreatment prior to melting the fly ash on the microstructure and properties of the glass-ceramics was examined. The results show that washing pretreatment of fly ash can decrease alkali metal chloride and increase network former in fly ash, which results in the increase of peak crystallization temperature of parent glass and strengthening of properties of bending strength and chemical stability of the glass-ceramics. The optimal heat treatment temperature for parent glass of washed fly ash is 1 173 K, at which the crystalline phase of glass-ceramics is composed of gelignite (Ca2A12SiO7) and akermanite (Ca2MgSi207). Glass-ceramics produced at optimal heat treatment temperature are excellent in term of the physical and chemical properties and leaching characteristics, indicating attractive potential as substitute of nature materials.展开更多
The careful studies have been made into the mutual solubility of water glass and water soluble organic binder in this paper, By means of many experiments, it has been found that water soluble polymer is able to be eve...The careful studies have been made into the mutual solubility of water glass and water soluble organic binder in this paper, By means of many experiments, it has been found that water soluble polymer is able to be evenly soluble in water glass, and certain valuable conclusions have been concluded.展开更多
Based on the composition of float glass, the resistance of glassto water, in which a small amount of K_2O(0-1.0 wt/100)wassubstituted for equivalent amount of Na_2O, was investigated by meansof glass grains testing. T...Based on the composition of float glass, the resistance of glassto water, in which a small amount of K_2O(0-1.0 wt/100)wassubstituted for equivalent amount of Na_2O, was investigated by meansof glass grains testing. The components extracted from the glass andtotal alkalinities in extraction solution were de- termined by atomicabsorption spectroscopy and neutralizing method, respectively. Thecomposition of the glass was 14.4 K_2O+ Na_2O, 4.0 MgO, 8.2 CaO, 1.4Al_2O_3, 72.0 SiO, and the minimum extraction radio of oxides(maximum durability)occurred at a K_2O/Na_2O radio of 0.051(byweight)due to the presence of the mixed- alkali effect.展开更多
Common opal was dissolved in NaOH lyes in rotating autoclaves. The starting material was characterized by X-ray diffraction and adsorption spectroscopy, thermal and chemical analysis, electron and atomic force microsc...Common opal was dissolved in NaOH lyes in rotating autoclaves. The starting material was characterized by X-ray diffraction and adsorption spectroscopy, thermal and chemical analysis, electron and atomic force microscopy. The opal proved to be an Opal-CT with a microstructure consisting of microcrystalline tridymite, traces of low-quartz, and amorphous parts built up by random packings of size distributed amorphous silica colloids. The dissolution conditions have been inspired by the technological process of hydrothermal water glass synthesis by dissolving silica. Temperature and time of the dissolution process as well as initial molar SiO2:Na2O (Rm) ratios of the starting materials were varied systematically. The particle size of the samples was varied, too, but due to the nanoscopic microstructure without greater impact on dissolution kinetics. The process products were analyzed chemically. Additionally, some of them were characterized by X-ray diffraction, viscosimetry and dynamic light scattering. Already after short dissolution times, water glasses with quite high silica concentrations of up to 27 wt.% and SiO2:Na2O ratios of up to 3.7 were obtained. At longer dissolution times low-quartz and analcime precipitated and the SiO2 contents were reduced to about 22 wt.% and Rm to about 2.7. The silica contents in equilibrium with low-quartz were almost independent on temperature.展开更多
The water collector is operated in the humid and hot environment of the cooling tower all the year round.It also needs to carry part of the weight of water and silt.Therefore,it is particularly critical to optimize th...The water collector is operated in the humid and hot environment of the cooling tower all the year round.It also needs to carry part of the weight of water and silt.Therefore,it is particularly critical to optimize the material of the water collector and improve its mechanical properties.Polyester,a general term of polymer obtained from polyols and polyacids,is a kind of engineering plastics with excellent properties and wide applications.Glass fiber is a reinforced plastic reinforcement material,and the biggest characteristic of it is the high tensile strength and good heat resistance.In this paper,glass fiber reinforced polyester resin composite material is prepared,its tensile properties and bending properties are tested,and the performance of the imported material JK2020B is compared and analyzed.The results show that the elastic modulus along the fiber direction is relatively high,but the interlayer force in the direction of thickness and width is very small.This review provides a guidance for production process.展开更多
In this paper, the content of water glass before and after adding modifying agent was measured by Trimethylsilyl-gas-chromatography. The experimental results showed that different modulus of water glass could generate...In this paper, the content of water glass before and after adding modifying agent was measured by Trimethylsilyl-gas-chromatography. The experimental results showed that different modulus of water glass could generate different content of mono-silicate acid and oligomeric silicate acid in water glass. After a period of storage, different modulus of water glass led to decrease of silicate content at different levels. Because higher content of Na<sub>2</sub>O in water glass tended to incur the alkaline polymerization, the occurrence of depolymerization of silicate species would lead to an increase of oligomeric silicate species, resulting in a drawback of silicate species content after a period of storage. And contrary to that, lower content of Na<sub>2</sub>O in water glass tended to incur the acidic polymerization. When the modifying agent was added to the newly made water glass, the amount of mono-silicate acid and oligomeric silicate acid also decreased. In modified water glass, the change of each silicate acid species was less than that in unmodified water glass. These results showed that the modifying agent retarded the aging of water glass. It had remarkable significance on the theory and practical application of water glass chemistry.展开更多
This work mainly involved the preparation of a nano-scale form-stable phase change material(PCM) consisting of capric and myristic acid(CA-MA) binary eutectic acting as thermal absorbing material and nano silicon ...This work mainly involved the preparation of a nano-scale form-stable phase change material(PCM) consisting of capric and myristic acid(CA-MA) binary eutectic acting as thermal absorbing material and nano silicon dioxide(nano-SiO_2) serving as the supporting material. Industrial water glass for preparation of the nano silicon dioxide matrix and CA-MA eutectic mixture were compounded by single-step sol-gel method with the silane coupling agent. The morphology, chemical characterization and form stability property of the composite PCM were investigated by transmission electron microscopy(TEM), scanning electron microscopy(SEM), Fourier-transform infrared(FT-IR) spectroscopy and polarizing microscopy(POM). It was indicated that the average diameter of the composite PCM particle ranged from 30-100 nm. The CA-MA eutectic was immobilized in the network pores constructed by the Si-O bonds so that the composite PCM was allowed no liquid leakage above the melting temperature of the CA-MA eutectic. Differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA) measurement were conducted to investigate the thermal properties and stability of the composite PCM. From the measurement results, the mass fraction of the CA-MA eutectic in the composite PCM was about 40%. The phase change temperature and latent heat of the composite were determined to be 21.15 ℃ and 55.67 J/g, respectively. Meanwhile, thermal conductivity of the composite was measured to be 0.208 W·m^(-1)·K^(-1) by using the transient hot-wire method. The composite PCM was able to maintain the surrounding temperature close to its phase change temperature and behaved well in thermalregulated performance which was verified by the heat storage-release experiment. This kind of form-stable PCM was supposed to complete thermal insulation even temperature regulation by the dual effect of relatively low thermal conductivity and phase change thermal storage-release properties. So it can be formulated that the nanoscale CA-MA/SiO_2 composite PCM with the form-stable property, good thermal storage capacity and relatively low thermal conductivity can be applied for energy conservation as a kind of thermal functional material.展开更多
The effects and heat transfer mode of water film and sprinkler system on the heat-resistant property associated with the insulation of a fireproof glass were investigated. In the experiments, fireproof glass with a si...The effects and heat transfer mode of water film and sprinkler system on the heat-resistant property associated with the insulation of a fireproof glass were investigated. In the experiments, fireproof glass with a size of 3 300 mm (height) × 2 200 mm (width) × 12 mm (thickness) was exposed to an oil pool fire with a power of approximately 1.4 MW. The experimental results show that the application of the water film or sprinkler system on the glass can effectively resist the intensive heat from the fire in the test due to the absorption of latent heat. The permitted period of integrity and insulation with a water film and a sprinkler system could be extended to 60 min. It should be noted that the temperature of the glass surface can be kept under 60 °C in a 60 min test. The experimental results suggest that it is feasible to substitute fireproof glass with water film for a fireproof door as long as the water film or sprinkler system can work stably and water can cover the whole surface of the fireproof glass.展开更多
Total internal reflection fluorescence spectroscopy (TIRF) and synchronous scanning technique were combined to study the adsorption behavior of the meso-tetrakis (4-sulfonatophenyl) porphyrin (TPPS) at the glass-water...Total internal reflection fluorescence spectroscopy (TIRF) and synchronous scanning technique were combined to study the adsorption behavior of the meso-tetrakis (4-sulfonatophenyl) porphyrin (TPPS) at the glass-water interface without any surfactant. The pH dependence of synchronous fluorescence signal at the interface was analyzed. Both unprotonated (TPPS4-) and diprotonated (H2TPPS2-) forms of TPPS were observed at the interface. But the interface favored the adsorption of. The apparent estimated pKa2 value shifted from 5.00 in the bulk solution to 2.7 at the interface. STIRF provides a good technique to study multi-component systems at the interface.展开更多
Solar water heaters which provide a cost-effective and environmental friendly approach to hot water generation are in widespread application. Evacuated tube solar water heaters perform better than flat plate solar wat...Solar water heaters which provide a cost-effective and environmental friendly approach to hot water generation are in widespread application. Evacuated tube solar water heaters perform better than flat plate solar water heaters as a result of their greater surface area exposed for sunlight absorption. Water-in-glass evacuated tube solar water heaters are widely used as compared to heat-pipe solar water heaters due to their short payback periods. In this study, the performance of water-in-glass evacuated tube solar water heater is investigated through experiments under the climatic conditions in Kenya. The results revealed a daily efficiency range of 0.58 - 0.65 and a daily final outlet temperature greater than 55<span style="white-space:normal;">°</span>C given an initial temperature of 25°C.展开更多
基金supported by the Program of Applied Basic Research Program of Shanxi Province,China (No.202103021223055)the Shanxi Scholarship Council of Chinathe Key R&D program of Shanxi Province,China (No.202102030201006)。
文摘As a heat-resistant wave-absorbing material,silicon carbide(SiC)aerogel has become a research hotspot at present.However,the most common silicon sources are organosilanes,which are costly and toxic.In this work,SiC aerogels were successfully prepared by using water glass as the silicon source.Specifically,the microstructure and chemical composition of SiC aerogels were controlled by adjusting the Si to C molar ratio during the sol–gel process,and the effect on SiC aerogel microwave absorption properties was investigated.The SiC aerogels prepared with Si:C molar ratio of 1:1 have an effective electromagnetic wave absorption capacity,with a minimum reflection loss value of-46.30 dB at 12.88 GHz and an effective frequency bandwidth of 4.02 GHz.They also have good physical properties,such as the density of0.0444 g/cm^(3),the thermal conductivity of 0.0621 W/(m·K),and the specific surface area of 1099 m^(2)/g.These lightweight composites with microwave-absorbing properties and low thermal conductivity can be used as thermal protection materials for space shuttles and reusable carriers.
文摘This paper concentrates on the development of glasses with self-cleaning surfaces exhibiting high water contact angles. In this study, we prepared super-hydrophobic nano-ceramic coated glass based on titania & silica using simple sol-gel & dip coating methods and studied the best composition of the coatings by altering ratios of titanium tetraisopropoxide (TTIP)/tetraethyl orthosilicate (TEOS) with different homogenizing agents. We characterized the coatings by surface roughness measurement, percentage of optical transmission, static contact angle, near-infrared (NIR) transmission, and diffuse reflectance. The fabrication of coatings on glass substrates played an important role in increasing the water contact angle of about 95° and visible & NIR transmission of about 90%. We compared our modified glass substrate with commercial low emissivity (Low E) glass using X-ray diffraction (XRD) analysis, which showed pure amorphous surface claiming excellent wettability and thus the prepared glass substrate could have a variety of applications in different fields.
文摘By using a downward penetration testing device, a large number of experiments were made to investigate the effects of surfactants (sodium succinate, sodium dodecyl sulfonate and dodecyl benzene sulfonic acid sodium salt) on the penetration ability of the calcium chloride and water glass solutions in four dust samples. The experimental results showed that the surfactants can enhance the penetration ability and decrease the surface tension of the calcium chloride and water glass solutions in great extent. After adding the surfactants in 0.2—0.6 wt.% to the solutions of calcium chloride and water glass in 5—25 wt.% respectively, the largest percent of penetration ability increases to 28% more. Among the three surfactants, the size of their effects on the penetration ability of calcium chloride and water solutions in the dust samples is dodecyl benzene sulfonic acid sodium salt, sodium dodecyl sulfonate and sodium succinate.The achieved conclusions are great significant for calcium chloride and water glass to be applied in the field of soil stabilization and raising dust control.
基金supported by the National Natural Science Foundation of China (No.50571018)
文摘Bulk metallic glass rings have the potential applications as annular gasket and active solder in special fields. The bulk metallic glass ring of ZГ41.2Ti13.8Cu12.5Ni10.0Be22.5 with the outer diameter, the inner diameter, and the thickness of 38, 36, and 5 mm, respectively, was prepared by using a special shaped quartz tube water quenching method. The mechanical properties along the whole cross section were investigated by a nanoindentation method, and no evident variation of the Young's modulus and hardness was found, further indicating the single amorphous structure. Amorphous ring and tube-shape parts with different dimensions can be produced by this method.
基金financially supported by the National Natural Science Foundation of China(No.51775204)
文摘Wet reclamation of waste sodium silicate-bonded sand produces much alkaline sewage and causes pollution. Recycling water glass from wet reclamation sewage of the waste sodium silicate-bonded sand can solve pollution issues and generate economic benefits. In this work, the wet reclamation sewage was filtered, and the filtrate was causticized with a quicklime powder to produce a lye. The effects of causticization temperature, causticization time, and the amount of quicklime powder on the causticization rate were studied. The lye was used to dissolve the silica in the filtration residue to prepare a sodium silicate solution. The effects of the mass of filtration residue, dissolution temperature, and dissolution time on sodium silicate modulus were studied. Finally, the recycled water glass was obtained by concentrating the sodium silicate solution, and the bonding strength of the recycled water glass was tested. The results showed that the causticization rate could be improved by increasing the amount of quicklime powder, causticization temperature, and causticization time, and the highest causticization rate was above 92%. Amorphous silica in the filtration residue dissolved in the lye. Increasing the amount of the filtration residue, dissolution temperature, and dissolution time could improve the sodium silicate modulus. The bonding strength of the recycled water glass was close to that of commercial water glass. The recycled water glass could be used as a substitute for the commercial water glass.
基金Projects(41472278,41202220)supported by the National Natural Science Foundation of ChinaProject(20120022120003)supported by the Research Fund for the Doctoral Program of Higher Education,China+1 种基金Project(2652012065)supported by the Fundamental Research Funds for the Central Universities,ChinaProject supported by Beijing Higher Education Young Elite Teacher Program,China
文摘The rheological behavior of phosphoric acid-water glass grout in different mixing ratios was studied. Grout made of water glass with Baume degree of 20° and 13.4% phosphoric acid by 1:1 volume ratio is found to be more effective in stopping water. Laboratory model test of water shutoff by grouting was conducted. Test results show that the diffusion length and water cutoff effect of the grout are significantly improved as the grout head is raised, due to the dilution of underground water, and it takes the grout longer than its gel time to cut off water.
基金co-financed by the European Union within the European Social Fund in the project"Mloda Kadra 2015+"
文摘The paper presents the research results of using an innovative method to reclaim the waste moulding sands containing water glass. Two of the examined processes are connected with "dry" or "wet" activation of inorganic binder in waste moulding sand mixtures physically hardened by microwave radiation. The sand mixtures consisting of high-silica sand and water-glass with average molar module 2.5, were subjected to the following cyclical process: mixing the components, compacting, microwave heating, cooling-down, thermally loading the mould to 800 °C, cooling-down to ambient temperature, and knocking-out. After being knocked-out, the waste moulding sands were subjected to either dry or wet activation of the binder. To activate thermally treated inorganic binder, each of the examined processes employed the surface phenomenon usually associated to mechanical reclamation. The study also covered possible use of some elements of wet reclamation to rehydrate waste binder. To evaluate the effectiveness of the two proposed methods of waste binder activation, selected strength and technological parameters were measured. After each subsequent processing cycle, the permeability, tensile strength and bending strength were determined. In addition, the surface of activated sand grains was examined with a scanning electron microscope. Analysis of the results indicates that it is possible to re-activate the used binder such as sodium silicate, and to stabilize the strength parameters in both activation processes. Permeability of the refreshed moulding sands strongly depends on the surface condition of high-silica grains. The wet activation process by wetting and buffering knocked-out moulding sands in closed humid environment makes it possible to reduce the content of refreshing additive in water-glass. The moulding sands cyclically prepared in both processes do not require the addition of fresh high-silica sand. The relatively high quality achieved in the refreshed moulding sands allows them to be reused for manufacture of next moulds. Thus, the two proposed methods for cyclically processing used moulding sands containing sodium silicate, subject to microwave hardening, are suitable for economic and ecological circulation moulding mixtures.
基金Funded by the National Natural Science Foundation of China(No.20806051)the Key Laboratory of Education Ministry for Solid Waste Management and Environment Safety(No.SWMES-2010-07)the Science and Technology Project of Housing and Urban-Rural Ministry(No.2010-K4-2)
文摘Production of glass-ceramics by sintering the molten slag obtained from electric arc furnace treatment of fly ash was investigated. The effect of washing pretreatment prior to melting the fly ash on the microstructure and properties of the glass-ceramics was examined. The results show that washing pretreatment of fly ash can decrease alkali metal chloride and increase network former in fly ash, which results in the increase of peak crystallization temperature of parent glass and strengthening of properties of bending strength and chemical stability of the glass-ceramics. The optimal heat treatment temperature for parent glass of washed fly ash is 1 173 K, at which the crystalline phase of glass-ceramics is composed of gelignite (Ca2A12SiO7) and akermanite (Ca2MgSi207). Glass-ceramics produced at optimal heat treatment temperature are excellent in term of the physical and chemical properties and leaching characteristics, indicating attractive potential as substitute of nature materials.
文摘The careful studies have been made into the mutual solubility of water glass and water soluble organic binder in this paper, By means of many experiments, it has been found that water soluble polymer is able to be evenly soluble in water glass, and certain valuable conclusions have been concluded.
文摘Based on the composition of float glass, the resistance of glassto water, in which a small amount of K_2O(0-1.0 wt/100)wassubstituted for equivalent amount of Na_2O, was investigated by meansof glass grains testing. The components extracted from the glass andtotal alkalinities in extraction solution were de- termined by atomicabsorption spectroscopy and neutralizing method, respectively. Thecomposition of the glass was 14.4 K_2O+ Na_2O, 4.0 MgO, 8.2 CaO, 1.4Al_2O_3, 72.0 SiO, and the minimum extraction radio of oxides(maximum durability)occurred at a K_2O/Na_2O radio of 0.051(byweight)due to the presence of the mixed- alkali effect.
文摘Common opal was dissolved in NaOH lyes in rotating autoclaves. The starting material was characterized by X-ray diffraction and adsorption spectroscopy, thermal and chemical analysis, electron and atomic force microscopy. The opal proved to be an Opal-CT with a microstructure consisting of microcrystalline tridymite, traces of low-quartz, and amorphous parts built up by random packings of size distributed amorphous silica colloids. The dissolution conditions have been inspired by the technological process of hydrothermal water glass synthesis by dissolving silica. Temperature and time of the dissolution process as well as initial molar SiO2:Na2O (Rm) ratios of the starting materials were varied systematically. The particle size of the samples was varied, too, but due to the nanoscopic microstructure without greater impact on dissolution kinetics. The process products were analyzed chemically. Additionally, some of them were characterized by X-ray diffraction, viscosimetry and dynamic light scattering. Already after short dissolution times, water glasses with quite high silica concentrations of up to 27 wt.% and SiO2:Na2O ratios of up to 3.7 were obtained. At longer dissolution times low-quartz and analcime precipitated and the SiO2 contents were reduced to about 22 wt.% and Rm to about 2.7. The silica contents in equilibrium with low-quartz were almost independent on temperature.
文摘The water collector is operated in the humid and hot environment of the cooling tower all the year round.It also needs to carry part of the weight of water and silt.Therefore,it is particularly critical to optimize the material of the water collector and improve its mechanical properties.Polyester,a general term of polymer obtained from polyols and polyacids,is a kind of engineering plastics with excellent properties and wide applications.Glass fiber is a reinforced plastic reinforcement material,and the biggest characteristic of it is the high tensile strength and good heat resistance.In this paper,glass fiber reinforced polyester resin composite material is prepared,its tensile properties and bending properties are tested,and the performance of the imported material JK2020B is compared and analyzed.The results show that the elastic modulus along the fiber direction is relatively high,but the interlayer force in the direction of thickness and width is very small.This review provides a guidance for production process.
文摘In this paper, the content of water glass before and after adding modifying agent was measured by Trimethylsilyl-gas-chromatography. The experimental results showed that different modulus of water glass could generate different content of mono-silicate acid and oligomeric silicate acid in water glass. After a period of storage, different modulus of water glass led to decrease of silicate content at different levels. Because higher content of Na<sub>2</sub>O in water glass tended to incur the alkaline polymerization, the occurrence of depolymerization of silicate species would lead to an increase of oligomeric silicate species, resulting in a drawback of silicate species content after a period of storage. And contrary to that, lower content of Na<sub>2</sub>O in water glass tended to incur the acidic polymerization. When the modifying agent was added to the newly made water glass, the amount of mono-silicate acid and oligomeric silicate acid also decreased. In modified water glass, the change of each silicate acid species was less than that in unmodified water glass. These results showed that the modifying agent retarded the aging of water glass. It had remarkable significance on the theory and practical application of water glass chemistry.
基金Funded by the National Natural Science Foundation of China(No.51308275)Natural Science Foundation of Liaoning Province(No.SY2016004)the Colleges and Universities Excellent Talents Supporting Plan Program of Liaoning Province(No.LJQ2015049)
文摘This work mainly involved the preparation of a nano-scale form-stable phase change material(PCM) consisting of capric and myristic acid(CA-MA) binary eutectic acting as thermal absorbing material and nano silicon dioxide(nano-SiO_2) serving as the supporting material. Industrial water glass for preparation of the nano silicon dioxide matrix and CA-MA eutectic mixture were compounded by single-step sol-gel method with the silane coupling agent. The morphology, chemical characterization and form stability property of the composite PCM were investigated by transmission electron microscopy(TEM), scanning electron microscopy(SEM), Fourier-transform infrared(FT-IR) spectroscopy and polarizing microscopy(POM). It was indicated that the average diameter of the composite PCM particle ranged from 30-100 nm. The CA-MA eutectic was immobilized in the network pores constructed by the Si-O bonds so that the composite PCM was allowed no liquid leakage above the melting temperature of the CA-MA eutectic. Differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA) measurement were conducted to investigate the thermal properties and stability of the composite PCM. From the measurement results, the mass fraction of the CA-MA eutectic in the composite PCM was about 40%. The phase change temperature and latent heat of the composite were determined to be 21.15 ℃ and 55.67 J/g, respectively. Meanwhile, thermal conductivity of the composite was measured to be 0.208 W·m^(-1)·K^(-1) by using the transient hot-wire method. The composite PCM was able to maintain the surrounding temperature close to its phase change temperature and behaved well in thermalregulated performance which was verified by the heat storage-release experiment. This kind of form-stable PCM was supposed to complete thermal insulation even temperature regulation by the dual effect of relatively low thermal conductivity and phase change thermal storage-release properties. So it can be formulated that the nanoscale CA-MA/SiO_2 composite PCM with the form-stable property, good thermal storage capacity and relatively low thermal conductivity can be applied for energy conservation as a kind of thermal functional material.
基金Project(2006BAK06B02) supported by the National Science and Technology Pillar Program during the Eleven Five-Year Plans of ChinaProject(70701019) supported by the National Natural Science Foundation of China
文摘The effects and heat transfer mode of water film and sprinkler system on the heat-resistant property associated with the insulation of a fireproof glass were investigated. In the experiments, fireproof glass with a size of 3 300 mm (height) × 2 200 mm (width) × 12 mm (thickness) was exposed to an oil pool fire with a power of approximately 1.4 MW. The experimental results show that the application of the water film or sprinkler system on the glass can effectively resist the intensive heat from the fire in the test due to the absorption of latent heat. The permitted period of integrity and insulation with a water film and a sprinkler system could be extended to 60 min. It should be noted that the temperature of the glass surface can be kept under 60 °C in a 60 min test. The experimental results suggest that it is feasible to substitute fireproof glass with water film for a fireproof door as long as the water film or sprinkler system can work stably and water can cover the whole surface of the fireproof glass.
文摘Total internal reflection fluorescence spectroscopy (TIRF) and synchronous scanning technique were combined to study the adsorption behavior of the meso-tetrakis (4-sulfonatophenyl) porphyrin (TPPS) at the glass-water interface without any surfactant. The pH dependence of synchronous fluorescence signal at the interface was analyzed. Both unprotonated (TPPS4-) and diprotonated (H2TPPS2-) forms of TPPS were observed at the interface. But the interface favored the adsorption of. The apparent estimated pKa2 value shifted from 5.00 in the bulk solution to 2.7 at the interface. STIRF provides a good technique to study multi-component systems at the interface.
文摘Solar water heaters which provide a cost-effective and environmental friendly approach to hot water generation are in widespread application. Evacuated tube solar water heaters perform better than flat plate solar water heaters as a result of their greater surface area exposed for sunlight absorption. Water-in-glass evacuated tube solar water heaters are widely used as compared to heat-pipe solar water heaters due to their short payback periods. In this study, the performance of water-in-glass evacuated tube solar water heater is investigated through experiments under the climatic conditions in Kenya. The results revealed a daily efficiency range of 0.58 - 0.65 and a daily final outlet temperature greater than 55<span style="white-space:normal;">°</span>C given an initial temperature of 25°C.