Effect of different particle sizes of cordierite on properties of castable refractory by different heat treatment temperatures were investigated respectively with mullite and bauxite as raw materials, calcium aluminat...Effect of different particle sizes of cordierite on properties of castable refractory by different heat treatment temperatures were investigated respectively with mullite and bauxite as raw materials, calcium aluminate cement as binders. After 24 h curing in mould and another 24 h curing at 110 ℃ after demoulding, the specimens were heat treated at 1 000 ℃, 1 300℃ and 1 500℃ for 3 h, respectively. The bulk density （ BD）, permanent linear change （ PLC）, modulus of rupture（MOR） and clod crushing strength（CCS）, thermal expansion coefficient and thermal shock resistance were examined. The results show that there is no obvious effect on adjusting permanent linear change and bulk density of castables by adding different particle sizes of cordierite at low temperature and intermediate temperature. Modulus of rupture of castable increase with the decreasing of the particle sizes of cordierite after heat treated by 1 000 ℃ and 1 300℃. In this experiment, thermal shock resistance of the castable with cordierite whose particle size is 0 - 1 mm is the best.展开更多
The present study evaluated the effect of feed particle size, thermal processing, several levels of fat inclusion and moisture addition on pellet quality and protein solubility in potassium hydroxide （KOH） in a corn...The present study evaluated the effect of feed particle size, thermal processing, several levels of fat inclusion and moisture addition on pellet quality and protein solubility in potassium hydroxide （KOH） in a corn, soybean meal and animal by products based broiler diets. The different processing factors were combined in a 2 x 4 x 4 x 2 factorial arrangement in an eight randomized block consisting of eight production series： two particle sizes （coarse： 1,041 microns and medium： 743 microns）, four fat inclusion levels at the mixer （15, 25, 35 and 45 g/kg of feed）, four moisture addition levels in the conditioner （0, 7, 14 and 21 g/kg of feed） and two thermal processing treatments （conditioner-pellet press treatment or conditioner-expander-pellet treatment） which resulted in 64 different processed feeds. For the determination of the pellet durability index （PDI）, the amount of intact pellets and protein solubility determinations, eight feed samples （replicates） were collected for each treatment. The data were transformed using a variation of Box-Cox transformation in order to fit a normal distribution （p 〉 0.05）. Adding moisture up to 21 g/kg of feed in the conditioner improved pellet quality of the diets （p 〈 0.05）. Expansion of diets before pelleting improved （P 〈 0.05） PDI and amount of intact pellets by 26% and 31%, respectively, as compared to a simple conditioning-pelleting feed processing. Expander treatment （at 110 ℃） decreased （p 〈 0.05） protein solubility in KOH from 686 g/kg to 643 g/kg total protein as compared to pelleting process （at 80-82 ℃）. The amount of intact pellets reduced from 773 g/kg to 746 g/kg of feed （/7 〈 0.05） as particle size increased from medium to coarse grinding. Pellet quality was significantly reduced with fat inclusion levels higher than 35 g/kg of diet.展开更多
Organic dust flames deal with a field of science in which many complicated phenomena like pyrolysis or devolatization of solid particles and combustion of volatile particles take place. One-dimensional flame propagati...Organic dust flames deal with a field of science in which many complicated phenomena like pyrolysis or devolatization of solid particles and combustion of volatile particles take place. One-dimensional flame propagation in cloud of fuel mixture is analyzed in which flame structure is divided into three zones. The first zone is preheat zone in which rate of the chemical reaction is small and transfer phenomena play significant role in temperature and mass distributions. In this model, it is assumed that particles pyrolyze first to yield a gaseous fuel mixture. The second zone is reaction zone where convection and vaporization rates of the particles are small. The third zone is convection zone where diffusive terms are negligible in comparison of other terms. Non-zero Biot number is used in order to study effect of particles thermal resistance on flame characteristics. Also, effect of particle size on combustion of micro organic dust is investigated. According to obtained results, it is understood that both flame temperature and burning velocity decrease with rise in the Biot number and particle size.展开更多
A novel modified expanded granular sludge bed(EGSBm) reactor was developed for anaerobic treatment of municipal sewage with mixed liquid recirculation instead of effluent recirculation commonly adopted by a convention...A novel modified expanded granular sludge bed(EGSBm) reactor was developed for anaerobic treatment of municipal sewage with mixed liquid recirculation instead of effluent recirculation commonly adopted by a conventional EGSB(EGSBc) reactor.Performances of these two reactors were compared in treating municipal sewage at ambient temperatures ranging from 8 to 26 ℃.At an upflow liquid velocity(Vup) of 10.3 m/h,the mean concentrations of filtrated COD(CODfilt) and COD of the EGSBm effluent were determined to be 59.4 and 95.9 mg/L,respectively,which were significantly lower than those of the EGSBc effluent operated under identical experimental conditions.When the organic loading rate was suddenly increased from 1.2 to 7.2 kg COD/(m3·d),the EGSBm regained the removal efficiency of previous operation phase in 10 d.Hydrodynamic characteristics of the reactors were compared using the residence time distribution(RTD) model.It was found that the treatment efficiency of EGSBm kept increasing as the Vup increased.The polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis(PCR-DGGE) technique was used to analyze the microbial diversity in EGSBm.Fingerprinting pattern indicated that some species in the inoculating sludge were still reserved in the granular sludge of EGSBm,moreover,several new species occurred.展开更多
The microwave absorption property and infrared emissivity have been investigated for the single-layer coating made of the epoxy-polyurethane resin and carbonyl iron powders with variation of annealing treatment. Micro...The microwave absorption property and infrared emissivity have been investigated for the single-layer coating made of the epoxy-polyurethane resin and carbonyl iron powders with variation of annealing treatment. Microwave-absorbing property was investigated by measuring the complex permittivity and complex permeability of the absorber in the frequency range from 2 to 18 GHz. Infrared emissivity value was measured using IR-2 Infrared Emissometer in the wavelength range of 8-14 μm. After annealing, the Fe （110） peak became sharp, and the crystallization improved significantly. Annealing treatment could reduce the sttrface energy of powders, improve compatibility between fillers and adhesives, and result in increase of the density of the coating. The lowest value of infrared emissivity （0.419） was obtained from the coating made of the carbonyl iron powder annealed at 700℃ for 1 h. With the variation of the annealing temperature, the magnetic and dielectric properties of the carbonyl iron particle were changed. The maximum reflection loss decreased and the matching frequency shifted to lower frequency with increasing the annealing temperature of carbonyl iron particles, which coincided with the variation of the complex permeability and permittivity according to the annealing temperature. Magnetic loss factor and dielectric loss factor of carbonyl iron particles were improved with increasing the annealing temperature in the 2-18 GHz range.展开更多
文摘Effect of different particle sizes of cordierite on properties of castable refractory by different heat treatment temperatures were investigated respectively with mullite and bauxite as raw materials, calcium aluminate cement as binders. After 24 h curing in mould and another 24 h curing at 110 ℃ after demoulding, the specimens were heat treated at 1 000 ℃, 1 300℃ and 1 500℃ for 3 h, respectively. The bulk density （ BD）, permanent linear change （ PLC）, modulus of rupture（MOR） and clod crushing strength（CCS）, thermal expansion coefficient and thermal shock resistance were examined. The results show that there is no obvious effect on adjusting permanent linear change and bulk density of castables by adding different particle sizes of cordierite at low temperature and intermediate temperature. Modulus of rupture of castable increase with the decreasing of the particle sizes of cordierite after heat treated by 1 000 ℃ and 1 300℃. In this experiment, thermal shock resistance of the castable with cordierite whose particle size is 0 - 1 mm is the best.
文摘The present study evaluated the effect of feed particle size, thermal processing, several levels of fat inclusion and moisture addition on pellet quality and protein solubility in potassium hydroxide （KOH） in a corn, soybean meal and animal by products based broiler diets. The different processing factors were combined in a 2 x 4 x 4 x 2 factorial arrangement in an eight randomized block consisting of eight production series： two particle sizes （coarse： 1,041 microns and medium： 743 microns）, four fat inclusion levels at the mixer （15, 25, 35 and 45 g/kg of feed）, four moisture addition levels in the conditioner （0, 7, 14 and 21 g/kg of feed） and two thermal processing treatments （conditioner-pellet press treatment or conditioner-expander-pellet treatment） which resulted in 64 different processed feeds. For the determination of the pellet durability index （PDI）, the amount of intact pellets and protein solubility determinations, eight feed samples （replicates） were collected for each treatment. The data were transformed using a variation of Box-Cox transformation in order to fit a normal distribution （p 〉 0.05）. Adding moisture up to 21 g/kg of feed in the conditioner improved pellet quality of the diets （p 〈 0.05）. Expansion of diets before pelleting improved （P 〈 0.05） PDI and amount of intact pellets by 26% and 31%, respectively, as compared to a simple conditioning-pelleting feed processing. Expander treatment （at 110 ℃） decreased （p 〈 0.05） protein solubility in KOH from 686 g/kg to 643 g/kg total protein as compared to pelleting process （at 80-82 ℃）. The amount of intact pellets reduced from 773 g/kg to 746 g/kg of feed （/7 〈 0.05） as particle size increased from medium to coarse grinding. Pellet quality was significantly reduced with fat inclusion levels higher than 35 g/kg of diet.
文摘Organic dust flames deal with a field of science in which many complicated phenomena like pyrolysis or devolatization of solid particles and combustion of volatile particles take place. One-dimensional flame propagation in cloud of fuel mixture is analyzed in which flame structure is divided into three zones. The first zone is preheat zone in which rate of the chemical reaction is small and transfer phenomena play significant role in temperature and mass distributions. In this model, it is assumed that particles pyrolyze first to yield a gaseous fuel mixture. The second zone is reaction zone where convection and vaporization rates of the particles are small. The third zone is convection zone where diffusive terms are negligible in comparison of other terms. Non-zero Biot number is used in order to study effect of particles thermal resistance on flame characteristics. Also, effect of particle size on combustion of micro organic dust is investigated. According to obtained results, it is understood that both flame temperature and burning velocity decrease with rise in the Biot number and particle size.
基金Sponsored by the National Natural Science Foundation of China(Grant No.20876117)National Key Technologies Research & Development Program(Grant No.2006BAJ08B10,2006BAJ04A07,2008BAJ08B21)
文摘A novel modified expanded granular sludge bed(EGSBm) reactor was developed for anaerobic treatment of municipal sewage with mixed liquid recirculation instead of effluent recirculation commonly adopted by a conventional EGSB(EGSBc) reactor.Performances of these two reactors were compared in treating municipal sewage at ambient temperatures ranging from 8 to 26 ℃.At an upflow liquid velocity(Vup) of 10.3 m/h,the mean concentrations of filtrated COD(CODfilt) and COD of the EGSBm effluent were determined to be 59.4 and 95.9 mg/L,respectively,which were significantly lower than those of the EGSBc effluent operated under identical experimental conditions.When the organic loading rate was suddenly increased from 1.2 to 7.2 kg COD/(m3·d),the EGSBm regained the removal efficiency of previous operation phase in 10 d.Hydrodynamic characteristics of the reactors were compared using the residence time distribution(RTD) model.It was found that the treatment efficiency of EGSBm kept increasing as the Vup increased.The polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis(PCR-DGGE) technique was used to analyze the microbial diversity in EGSBm.Fingerprinting pattern indicated that some species in the inoculating sludge were still reserved in the granular sludge of EGSBm,moreover,several new species occurred.
基金supported by the National Natural Science Foundation of China (Grant No. 90505008)the Weaponry Equipment Preresearch Foundation of China (Grant No. 51410040305HK0214)
文摘The microwave absorption property and infrared emissivity have been investigated for the single-layer coating made of the epoxy-polyurethane resin and carbonyl iron powders with variation of annealing treatment. Microwave-absorbing property was investigated by measuring the complex permittivity and complex permeability of the absorber in the frequency range from 2 to 18 GHz. Infrared emissivity value was measured using IR-2 Infrared Emissometer in the wavelength range of 8-14 μm. After annealing, the Fe （110） peak became sharp, and the crystallization improved significantly. Annealing treatment could reduce the sttrface energy of powders, improve compatibility between fillers and adhesives, and result in increase of the density of the coating. The lowest value of infrared emissivity （0.419） was obtained from the coating made of the carbonyl iron powder annealed at 700℃ for 1 h. With the variation of the annealing temperature, the magnetic and dielectric properties of the carbonyl iron particle were changed. The maximum reflection loss decreased and the matching frequency shifted to lower frequency with increasing the annealing temperature of carbonyl iron particles, which coincided with the variation of the complex permeability and permittivity according to the annealing temperature. Magnetic loss factor and dielectric loss factor of carbonyl iron particles were improved with increasing the annealing temperature in the 2-18 GHz range.
