[Objective] The aim was to observe the puff-by-puff transfer ratios of some flavors in cigarettes.[Method] Based on national standards,the puff-by-puff transfer of tobacco of carbonyl flavors was analyzed.In the meant...[Objective] The aim was to observe the puff-by-puff transfer ratios of some flavors in cigarettes.[Method] Based on national standards,the puff-by-puff transfer of tobacco of carbonyl flavors was analyzed.In the meantime,by dint of simultaneous distillation and extraction equipment coupled to GC and GC/MS,the puff-by-puff transfer ratios to TPM of smoke were expounded and compared.[Result] The puff-by-puff delivery profiles of NFDPT,nicotine and carbon monoxide increased with increasing puff number.This trend was similar to that of particulate matters.The transfer ratio of flavored tobacco was increasing in general,but partial flavors augmented to the maximum value and then decreased slowly.[Conclusion] The study provided reference for the application of carbonyl compounds in tobacco.展开更多
The phase ratio has been found to affect the packing efficiency in packed columns.To ac-count for the effect,a model is set up to correlate the height of a mass transfer unit with the phaseratio with reasonable accura...The phase ratio has been found to affect the packing efficiency in packed columns.To ac-count for the effect,a model is set up to correlate the height of a mass transfer unit with the phaseratio with reasonable accuracy.Proposed also is a correlation that allows to predict the efficiency inquestion at any given liquid-gas ratio using the knowledge of other efficiency values at other liquid-gas ratios.展开更多
The heat transfer augmentation of plain twisted tape inserts for different twist ratios has been studied in this study. The data are conducted using the plain twisted tape insert with five different twist ratios respe...The heat transfer augmentation of plain twisted tape inserts for different twist ratios has been studied in this study. The data are conducted using the plain twisted tape insert with five different twist ratios respectively. The range of Reynolds number is considered under a uniform heat flux condition. In the case of simulation, the tapes are made from a stainless steel strip with a thickness of 2 mm. A tubular pipe with 850mm U-loop length and twist length of 800 mm each is considered in our study for simulation. Water is used as working fluids inside the tube for our simulation. The simulation results demonstrate that the important heat transfer parameters including Nusselt number (Nu), friction factor (f) and thermal performance index (η) are gradually increased with the increment of the twist ratio and reached at the saturated level while twist ratio is 3.5,?afterward the thermal properties are decreased.展开更多
Heat transfer and entropy generation of developing laminar forced convection flow of water-Al_2O_3 nanofluid in a concentric annulus with constant heat flux on the walls is investigated numerically. In order to determ...Heat transfer and entropy generation of developing laminar forced convection flow of water-Al_2O_3 nanofluid in a concentric annulus with constant heat flux on the walls is investigated numerically. In order to determine entropy generation of fully developed flow, two approaches are employed and it is shown that only one of these methods can provide appropriate results for flow inside annuli. The effects of concentration of nanoparticles, Reynolds number and thermal boundaries on heat transfer enhancement and entropy generation of developing laminar flow inside annuli with different radius ratios and same cross sectional areas are studied. The results show that radius ratio is a very important decision parameter of an annular heat exchanger such that in each Re, there is an optimum radius ratio to maximize Nu and minimize entropy generation. Moreover, the effect of nanoparticles concentration on heat transfer enhancement and minimizing entropy generation is stronger at higher Reynolds.展开更多
The complexation between styrene (St) and N-phenylmaleimide (PMI) was investigated by H-1-NMR spectroscopy, and the existence of a complex was proved. The equilibrium constant of St/PMI in chloroform at 50 degrees C w...The complexation between styrene (St) and N-phenylmaleimide (PMI) was investigated by H-1-NMR spectroscopy, and the existence of a complex was proved. The equilibrium constant of St/PMI in chloroform at 50 degrees C was determined to be 0.27. New elementary propagation reactions were proposed. On the basis of the propagation elementary reactions for copolymerization with the participation of a charge-transfer complex (CTC), a method for measuring the reactivity ratios is presented. Four reactivity ratios and relative reactivities of free monomer and CTC were obtained. They are r(12) = 0.034, r(21) = 0.012, r(1C) = 0.0030, r(2C) = 0.0034, and k(1C)/k(12) = 11.34, k(2C)/k(21) = 3.42.展开更多
文摘[Objective] The aim was to observe the puff-by-puff transfer ratios of some flavors in cigarettes.[Method] Based on national standards,the puff-by-puff transfer of tobacco of carbonyl flavors was analyzed.In the meantime,by dint of simultaneous distillation and extraction equipment coupled to GC and GC/MS,the puff-by-puff transfer ratios to TPM of smoke were expounded and compared.[Result] The puff-by-puff delivery profiles of NFDPT,nicotine and carbon monoxide increased with increasing puff number.This trend was similar to that of particulate matters.The transfer ratio of flavored tobacco was increasing in general,but partial flavors augmented to the maximum value and then decreased slowly.[Conclusion] The study provided reference for the application of carbonyl compounds in tobacco.
文摘The phase ratio has been found to affect the packing efficiency in packed columns.To ac-count for the effect,a model is set up to correlate the height of a mass transfer unit with the phaseratio with reasonable accuracy.Proposed also is a correlation that allows to predict the efficiency inquestion at any given liquid-gas ratio using the knowledge of other efficiency values at other liquid-gas ratios.
文摘The heat transfer augmentation of plain twisted tape inserts for different twist ratios has been studied in this study. The data are conducted using the plain twisted tape insert with five different twist ratios respectively. The range of Reynolds number is considered under a uniform heat flux condition. In the case of simulation, the tapes are made from a stainless steel strip with a thickness of 2 mm. A tubular pipe with 850mm U-loop length and twist length of 800 mm each is considered in our study for simulation. Water is used as working fluids inside the tube for our simulation. The simulation results demonstrate that the important heat transfer parameters including Nusselt number (Nu), friction factor (f) and thermal performance index (η) are gradually increased with the increment of the twist ratio and reached at the saturated level while twist ratio is 3.5,?afterward the thermal properties are decreased.
文摘Heat transfer and entropy generation of developing laminar forced convection flow of water-Al_2O_3 nanofluid in a concentric annulus with constant heat flux on the walls is investigated numerically. In order to determine entropy generation of fully developed flow, two approaches are employed and it is shown that only one of these methods can provide appropriate results for flow inside annuli. The effects of concentration of nanoparticles, Reynolds number and thermal boundaries on heat transfer enhancement and entropy generation of developing laminar flow inside annuli with different radius ratios and same cross sectional areas are studied. The results show that radius ratio is a very important decision parameter of an annular heat exchanger such that in each Re, there is an optimum radius ratio to maximize Nu and minimize entropy generation. Moreover, the effect of nanoparticles concentration on heat transfer enhancement and minimizing entropy generation is stronger at higher Reynolds.
文摘The complexation between styrene (St) and N-phenylmaleimide (PMI) was investigated by H-1-NMR spectroscopy, and the existence of a complex was proved. The equilibrium constant of St/PMI in chloroform at 50 degrees C was determined to be 0.27. New elementary propagation reactions were proposed. On the basis of the propagation elementary reactions for copolymerization with the participation of a charge-transfer complex (CTC), a method for measuring the reactivity ratios is presented. Four reactivity ratios and relative reactivities of free monomer and CTC were obtained. They are r(12) = 0.034, r(21) = 0.012, r(1C) = 0.0030, r(2C) = 0.0034, and k(1C)/k(12) = 11.34, k(2C)/k(21) = 3.42.
