The vaporization ratios of the slurry at various temperature and partial pressure were calculated with the group-contribution method,and then the phase state of the slurry in the residue fluid catalytic cracking(RFCC)...The vaporization ratios of the slurry at various temperature and partial pressure were calculated with the group-contribution method,and then the phase state of the slurry in the residue fluid catalytic cracking(RFCC) disengager was determined.This research could provide some advices on how to select the technological conditions to decrease the coking in the RFCC disengager.The oil gas temperature and the slurry partial pressure had signifi- cant effects on the vaporization ratio of the slurry.Increasing the oil gas temperature and reducing the slurry partial pressure could effectively slow down the coking speed in the RFCC disengager.According to the calculation results, a correlation was established to predict the vaporization ratio of the slurry under different operating conditions.展开更多
In this study, the vaporization ratio of the 2-μm laser in the prostatic tissue with benign prostatic hyperplasia was examined in vitro, to explore a technique to estimate the clearance rate of prostatic tissue durin...In this study, the vaporization ratio of the 2-μm laser in the prostatic tissue with benign prostatic hyperplasia was examined in vitro, to explore a technique to estimate the clearance rate of prostatic tissue during the transurethral vaporesection of the prostate. A total of 9 fresh prostatic tissue specimens were obtained by open surgery and the wet weight of the prostatic tissue were measured immediately after the sample collection. Under the simulated conditions of transurethral vaporesection of the prostate by 2-μm laser, each prostate gland was completely vaporesected into fragments with a diameter of less than 1.0 cm in vitro tissue were collected and measured. Then After the vaporesection, the whole fragments of prostatic the lost weight of prostatic tissue, the weight of the collected prostatic tissue and the ratio of the lost weight of prostatic tissue to the wet weight of the prostate glandular organ specimen were calculated. The correlation between the weight of collected prostatic tissue and the weight of the whole glandular organ was analyzed. All the experimental procedures were carried out by one operator. Wet weight of the prostatic gland specimen and the weight of the harvested prostatic tissues after the procedure were recorded. With respect to the wet weight of prostate gland specimen, the percentage of the weight of collected prostatic tissue was (34.45±1.51) %, and the percentage of the lost weight of prostatic tissue was (65.55±1.51)%. Satisfactory linear relationship was observed between the weight of collected prostatic tissue and the wet weight of prostate gland specimen [y=3.245x=6.475 (t=15.097, P=0.000)]. It is concluded that under the simulated conditions of transurethral vaporesection of the prostate by 2-μm laser, the vaporization ratio of prostatic tissue can be calculated on the basis of the weight of collected prostatic tissue, and thereby the clearance of prostatic tissue during the formal operation by 2-μm laser could be quantitatively determined.展开更多
In the industrial production, the mixing of gas-liquid flow with vapor and gas-solid flow is a very common problem. In the process of the mixing, solid particle-clusters will form, and will have steady radii when the ...In the industrial production, the mixing of gas-liquid flow with vapor and gas-solid flow is a very common problem. In the process of the mixing, solid particle-clusters will form, and will have steady radii when the effect of the gathering of particles is balanced withthat of the breaking of particle-clusters. Then, the population distribution function of size of particles per unit length per unit volume is introduced, and its governingequation is derived on the analogy of the molecular kinetic theory. Finally, when the gas flow is very slow, the expression of steady average radius of particle-clusters is obtained.展开更多
Biohydrogen production from synthetic waste, SW (model organic fraction of municipal solid waste) co-digested with liquid dairy manure (M) was tested in batch reactions to assess the effect of temperature and mixi...Biohydrogen production from synthetic waste, SW (model organic fraction of municipal solid waste) co-digested with liquid dairy manure (M) was tested in batch reactions to assess the effect of temperature and mixing ratio of the substrates. A 5 × 2 factorial design experiment was conducted. Synthetic waste: manure mixtures of 1:1, 2:1, 3:1, 1:0, 0:1 (volatile solids, VS, basis) were tested at 37 (T37) and 55 ℃ (T55) using thirty 1 L laboratory scale digesters. Total VS of each mixture was 50 g/L except SW:M 0:I treatment, where total VS was 27.4 g/L. Gas samples were taken daily to determine hydrogen production, and slurry samples taken before and after experimentation, were analyzed for volatile fatty acid (VFA) concentration, volatile solid (VS) degradation, ammonium nitrogen (NH4+-N) and pH. Hydrogen production (mL/g-VS fed) showed a significant two-factor interaction between incubation temperature and SW:M ratio (P 〈 0.001). Maximum production of 15.8 mL/g-VS (fed) was achieved in SW:M ratio of 3:1 at 55 ℃. Generally, hydrogen productions at thermophilic temperature (T55) were significantly higher than at mesophilic (T37) temperature for all treatments (P 〈 0.001) except for SW:M 1:0 and SW:M 0:1 treatments (P 〉 0.05). This study indicates that hydrogen production from co-digestion of synthetic waste and manure is dependent on incubation temperature and relative contribution of wastes in the mixture.展开更多
The instrumentation, method and measurement results used for measurements of CO2 concentrations in surface air of Obninsk (55.1° N, 36.9° E, 183 m above the sea level) located at a distance of 105 km to th...The instrumentation, method and measurement results used for measurements of CO2 concentrations in surface air of Obninsk (55.1° N, 36.9° E, 183 m above the sea level) located at a distance of 105 km to the south-west of Moscow are presented. Proposed is a method of experimental data filtering allowing one to separate natural and anthropogenic variations of CO2 concentrations. It is shown that minimal concentrations of CO2 registered in Obninsk and at the continental stations of GAW WMO characterize not only the "regional background" but also coincide with the data from GAW WMO background stations located in the oceanic regions. In this connection, one can assume that the excess in measured CO2 concentration over its minimal values, making about 5-6 ppm, is connected with an anthropogenic emission, and the continent should be considered as an anthropogenic source of C02.展开更多
Methane (CH4) emissions estimated with the Intergovernmental Panel on Climate Change (IPCC) inventory method at the city and regional scale are subject to large uncertainties.In this study,we determined the CH4:C...Methane (CH4) emissions estimated with the Intergovernmental Panel on Climate Change (IPCC) inventory method at the city and regional scale are subject to large uncertainties.In this study,we determined the CH4:CO2 emissions ratio for both Nanjing and the Yangtze River Delta (YRD),using the atmospheric CH4 and CO2 concentrations measured at a suburban site in Nanjing in the winter.The atmospheric estimate of the CH4:CO2 emissions ratio was in reasonable agreement with that calculated using the IPCC method for the YRD (within 20%),but was 200% greater for the municipality of Nanjing.The most likely reason for the discrepancy is that emissions from unmanaged landfills are omitted from the official statistics on garbage production.展开更多
Starch/polylactic acid(PLA) composites were prepared by melt extrusion, with corn starch and PLA as raw materials, glycerol as the plasticizer. Effects of starch/PLA ratio on the interdependence of two-phase and other...Starch/polylactic acid(PLA) composites were prepared by melt extrusion, with corn starch and PLA as raw materials, glycerol as the plasticizer. Effects of starch/PLA ratio on the interdependence of two-phase and other properties of the composites were studied. The combination of results of TGA with SEM indicated that the interdependence between starch and PLA was increased gradually as the starch/PLA ratio reduced. DSC results showed that the glass transition temperature(Tg), melting temperature(Tm) and degree of crystallinity of PLA in composites were increased gradually, whereas the cold crystallization temperature(Tc) was gradually decreased as the starch/PLA ratio reduced. The rheological properties of composites were closely related with the interdependence of two-phase, with reducing starch/PLA proportion, the interdependence was increased, and then the strain for storage modulus was firstl reduced and then gradually increased. Frequency scanning showed that the storage modulus and complex viscosity were decreased with reducing starch content. As the starch/PLA ratio reduced, the matrix phase PLA was increased, so that the strength of composites was increased gradually, whereas water absorption rate was decreased gradually.展开更多
Operability problem of dividing wall column (DWC) raised by vapor split was investigated by numerically analyzing four cases defined by different compositions of a three-component mixture. DWCs were firstly designed f...Operability problem of dividing wall column (DWC) raised by vapor split was investigated by numerically analyzing four cases defined by different compositions of a three-component mixture. DWCs were firstly designed for each case by optimizing the vapor split to the two sides of the dividing wall, and then their feasibilities and total annual costs in operation were evaluated against different vapor split ratios. The analysis on the operability of the DWC for four cases was made based on two scenarios: (1) vapor split is shifted by the vapor resistance difference between the column sections in the two sides of the dividing wall and (2) the feed composition is changed. It was demonstrated that the positioning of the dividing wall and the decision on the vapor split may affect significantly the operability of a DWC.展开更多
Tho Gudui geothermal field records the highest temperature at equivalent borehole depths among the lainland hydrothermal systems in China's Mainland.Located about 150 km southeast of Lhasa City,the capital of Tibe...Tho Gudui geothermal field records the highest temperature at equivalent borehole depths among the lainland hydrothermal systems in China's Mainland.Located about 150 km southeast of Lhasa City,the capital of Tibet,the Gudui geothermal field belongs to the Sangri-Cuona rift belt,also known as the Sangri-Cuona geothermal belt,and is representative of the non-volcanic geothermal systems in the Himalayas.In this study,oxygen-18 and deuterium isotope compositions as well as 87Sr/86Sr ratios of water samples collected from the Gudui geothermal field were characterized to understand the origin and mixing processes of the geothermal fluids at Gudui.Hydrogen and oxygen isotope plots show both,deep and shallow reservoirs in the Gudui geothermal field.Deep geothermal fluids are the mixing product of magmatic and infiltrating snow-melt water.Calculations show that the magma fluid component of the deep geothermal fluids account for about 21.10%-24.04%;magma fluids lay also be a contributing source of lithium.The linear relationship of the 87Sr/86Sr isotopic ratio versus the 1/Sr plot indicates that shallow geothermal fluids form from the mixing of deep geothermal fluids with cold groundwater.Using a binary mixing model with deep geothermal fluid and cold groundwater as two end-members,the nixing ratios of the latter in most surface hot springs samples were calculated to be between 5% and 10%.Combined with basic geological characteristics,hydrogen and oxygen isotope characteristics,strontium concentration,87Sr/(86)Sr ratios,and the binary mixing model,we infer the 6 th-Class Reservoirs Evolution Conceptual Model(6-CRECM) for the Gudui geothermal system.This model represents an idealized summary of the characteristics of the Gudui geothermal field based on our comprehensive understanding of the origin and mixing processes of the geothermal fluid in Gudui.This study may aid in identifying the geothermal and geochemical origin of the Gudui high-temperature hydrothermal systems in remote Tibet of China,whose potential for geothermal development and utilization is enormous and untapped.展开更多
The prediction model for mechanical properties of RAC was established through the Bayesian optimization-based Gaussian process regression(BO-GPR)method,where the input variables in BO-GPR model depend on the mix ratio...The prediction model for mechanical properties of RAC was established through the Bayesian optimization-based Gaussian process regression(BO-GPR)method,where the input variables in BO-GPR model depend on the mix ratio of concrete.Then the compressive strength prediction model,the material cost,and environmental factors were simultaneously considered as objectives,while a multi-objective gray wolf optimization algorithm was developed for finding the optimal mix ratio.A total of 730 RAC datasets were used for training and testing the predication model,while the optimal design method for mix ratio was verified through RAC experiments.The experimental results show that the predicted,testing,and expected compressive strengths are nearly consistent,illustrating the effectiveness of the proposed method.展开更多
A bound state formalism derived from a fermion-boson symmetric Lagrangian has been used to calculate the nucleon masses, the charge neutrality of the neutron, the magnetic moments and the electromagnetic form factor r...A bound state formalism derived from a fermion-boson symmetric Lagrangian has been used to calculate the nucleon masses, the charge neutrality of the neutron, the magnetic moments and the electromagnetic form factor ratios μpGEp/GMpand μnGEn/GMn. A quantitative description is obtained, assuming a mixing of a scalar bound state of 3(f f¯)fstructure with its corresponding vector (f f¯)fstate (f indicating massless elementary fermions). Only a few parameters are needed, mainly fixed by energy and momentum conservation. The nucleon stability is explained by an extra binding in the confinement potential, negative for electric and positive for magnetic binding of the proton, and opposite for the neutron. The stronger electric extra binding of the proton allows a decay of the neutron to proton and electron.展开更多
Some copolymers of 2,4-dichlorophenyl acrylate (2,4-DCPA) with styrene (St) of different teed compositions were prepared by tree radical polymerization technique using 2,2′-azobisisobutyronitrile (AIBN) as an initiat...Some copolymers of 2,4-dichlorophenyl acrylate (2,4-DCPA) with styrene (St) of different teed compositions were prepared by tree radical polymerization technique using 2,2′-azobisisobutyronitrile (AIBN) as an initiator,and the copolymers were characterized by IR spectroscopy.The copolymer composition obtained by UV-spectra led to determination of reactivity ratio by employing Fineman-Ross (F-R) and Kelen-Tudos (K-T) methods.Average molecular weight,as well as intrinsic viscosity,was obtained by vapor pressu...展开更多
This paper studies the insurer’s solvency ratio model in a class of mixed fractional Brownian motion(MFBM) market, where the prices of assets follow a Wick-It? stochastic differential equation driven by the MFBM, by ...This paper studies the insurer’s solvency ratio model in a class of mixed fractional Brownian motion(MFBM) market, where the prices of assets follow a Wick-It? stochastic differential equation driven by the MFBM, by the method of the stochastic calculus of the MFBM and the pricing formula of European call option for the MFBM, the explicit formula for the expected present value of shareholders’ terminal payoff is given. The model extends the existing results.展开更多
An improved model to calculate the length of the mixing chamber of the ejector was proposed on the basis of the Fano flow model,and a method to optimize the structures of the mixing chamber and diffuser of the ejector...An improved model to calculate the length of the mixing chamber of the ejector was proposed on the basis of the Fano flow model,and a method to optimize the structures of the mixing chamber and diffuser of the ejector was put forward.The accuracy of the model was verified by comparing the theoretical results calculated using the model to experimental data reported in literature.Variations in the length of the mixing chamber L_(m) and length of the diffuser L_(d) with respect to variations in the outlet temperature of the ejector T_(c),outlet pressure of the ejector p_(c),and the expansion ratio of the pressure of the primary flow to that of the secondary flow p_(g)/p_(e) were investigated.Moreover,variations in L_(m) and L_(d) with respect to variations in the ratio of the diameter of the throat of the motive nozzle to the diameter of the mixing chamber d_(g0)/d_(c3) and ratio of the outlet diameter of the diffuser to the diameter of themixing chamber d_(c)/d_(c3) were investigated.The distribution of flow fields in the ejector was simulated.Increasing L_(m) and d_(c3) reduced T_(c) and p_(c).Moreover,reducing p_(g)/p_(e) or d_(g0)/d_(c3) reduced T_(c) and p_(c).The length of the mixed section L_(m2),which was determined on the basis of the Fano flow model,increased as pg increased and decreased as d_(c3) increased.The mixing length L_(m1),which was considered the primary flow expansion,showed the opposite trend with that of L_(m2).Moreover,Ld increased as p_(g)/p_(e) and d_(c)/d_(c3) increased.When the value of d_(c) was 1.8 to 2.0 times as high as that of dc3,the semi-cone angle of the diffuser ranged between 6°and 12°.At a constant dc/dc3,decreasing T_(c) and pc increased Ld.展开更多
A topographic target light scattering-differential optical absorption spectroscopy ('IbTaL-DOA~) system is de- veloped for measuring average concentrations along a known optical path and studying surface-near distr...A topographic target light scattering-differential optical absorption spectroscopy ('IbTaL-DOA~) system is de- veloped for measuring average concentrations along a known optical path and studying surface-near distributions of atmospheric trace gases. The telescope of the ToTaL-DOAS system points to targets which are located at known dis- tances from the measurement device and illuminated by sunlight. Average concentrations with high spatial resolution can be retrieved by receiving sunlight reflected from the targets, A filed measurement of NO2 concentration is performed with the ToTaL-DOAS system in Shijiazhuang in the autumn of 2011. The measurement data are compared with con- centrations measured by the point monitoring technique at the same site. The results show that the ToTaL-DOAS system is sensitive to the variation of NO2 concentrations along the optical path.展开更多
In this paper, through the indoor free load swelling rate test, expansive soil in a section of a first- class highway reconstruction project in Yichang City was studied. It emphatically analyzed the interrelations amo...In this paper, through the indoor free load swelling rate test, expansive soil in a section of a first- class highway reconstruction project in Yichang City was studied. It emphatically analyzed the interrelations among free load swelling rate, non-load time, the proportion of mixed sand and initial dry density. Experimen- tal studies have shown that: Free load swelling deformation is mainly divided into three stages of rapid expan- sion, slow expansion and final stability; when the initial dry density is constant, free load swelling rate of the weathered sand modified soil will reduce rapidly before they slow down with the increase of sand proportion, and weathered sand modified soil free load swelling rate is not sensitive to the large amount of sand mixed; in the same mixed sand ratio, weathered sand modified soil free load swelling rate increases rapidly with the in- crease of initial dry density, there is a good linear correlation between them. To take appropriate control of the initial dry density during the expansive soil subgrade construction helps to reduce its swelling deformation and ensures the stability of the embankment.展开更多
The air-turbo-rocket(ATR)engine is a promising propulsion plant for achieving numerous surface and air launched missile missions.The application of lobed mixer in the ATR combustor can promote the mixing of the fuelri...The air-turbo-rocket(ATR)engine is a promising propulsion plant for achieving numerous surface and air launched missile missions.The application of lobed mixer in the ATR combustor can promote the mixing of the fuelrich gas and the air,thus improving the engine performance significantly.The numerical simulation method was conducted to explore the effects of lobe peak-to-trough width ratio on mixing and combustion performance in ATR combustors.Results show that:For a given peak lobe width b1,the combustion efficiency and total pressure loss decrease with the increase of trough lobe width b2;For a given b2,the combustion efficiency and total pressure loss decrease with the increase of b1;The fan-type lobed mixer with smaller b2has a better effect on promoting the combustion efficiency in the region near the ATR combustor center line than that with a pair of parallel side walls.The total pressure recovery coefficient reaches more than 0.99 at the exit of combustor in nonreactive combustion while the total pressure loss reaches more than 4%in the reacting combustion.Compared with the mixing process,more than80%of the total pressure loss is caused during combustion.展开更多
In recent years, the rationalization of concrete mix ratios which batches equal volumes of sand and gravel in building projects has been gaining grounds in the Cameroon construction industry. The main objective of thi...In recent years, the rationalization of concrete mix ratios which batches equal volumes of sand and gravel in building projects has been gaining grounds in the Cameroon construction industry. The main objective of this study is therefore to investigate if the concrete produced with rationalized mix ratio can be adopted as conventional mix ratio in terms of minimum required compression strength of concrete for buildings. Specifically this work compared the conventional mix ratio of 350 kg of cement: 400 liters of sand: 800 liters of gravel for a cubic meter and the rationalized batch of 350 kg of cement: 600 liters of sand: 600 liters of 5/15 gravel, 15/25 gravel and a combination of 5/15 + 15/25 gravel. Average compressive tests’results for both the conventional and the rationalized mix ratios were found to meet the minimum compressive strength of 65% at 7 days, 90% at 14 days and 99% at 28 days for gravel size combination 5/15 + 15/25. Single size gravel of 5/15 and 15/25 did not meet the minimum required compressive strength of 20 N/mm<sup>2</sup> for the rationalized mix ratio at 28 days curing based on the minimum compressive strength required, this study arrives at the conclusion that the equal volumes of sand and gravel mix ratio of 350 kg/m<sup>3</sup> of cement: 600 liters of sand: 600 liters of gravel mix ratio can be adopted as a conventional concrete mix ratio for gravel size 5/15 + 15/25.展开更多
A new excess Gibbs free energy/equation of state type mixing 0rule was derived byremoving the infinite pressure boundary condition imposed by Wong and Sandler.The mixing rulewas extensively tested in terms of a compre...A new excess Gibbs free energy/equation of state type mixing 0rule was derived byremoving the infinite pressure boundary condition imposed by Wong and Sandler.The mixing rulewas extensively tested in terms of a comprehensive data base,consisting of 52 simple nonpolar-nonpolar,carbon dioxide containing,hydrocarbon-hydrocarbon,CFC,polar-polar,nonpolar-polarbinary and multicomponent systems.Focused on the complete predictive capability,a comparisonbetween the Wong-Sandler and the mixing rule proposed was conducted.The results indicate that thenew mixing rule is in general superior to the Wong-Sandler’s,and the binary interaction parameteras required by the latter is removed,which reduces computing effort and is reliable in predictions ofvapor-liquid equilibria from low pressures to high pressures.展开更多
The multipole mixing ratios have been calculated by a2-ratio method, from levels of 93Mo(p, nγ) reaction. The branching ratios of such γ-transitions are used to calculate the total gamma widths. Besides, the trans...The multipole mixing ratios have been calculated by a2-ratio method, from levels of 93Mo(p, nγ) reaction. The branching ratios of such γ-transitions are used to calculate the total gamma widths. Besides, the transition strengths and probabilities have been calculated for γ-transitions from excited states whose life times have been reported previously. The results are found to be in general in good agreement with the previous results populated from the previous work.展开更多
基金Supported by the National-Natural Science Foundation of China (No.20406013) and Program for New Century Excellent Talents in University (No.NCET-04-0107).
文摘The vaporization ratios of the slurry at various temperature and partial pressure were calculated with the group-contribution method,and then the phase state of the slurry in the residue fluid catalytic cracking(RFCC) disengager was determined.This research could provide some advices on how to select the technological conditions to decrease the coking in the RFCC disengager.The oil gas temperature and the slurry partial pressure had signifi- cant effects on the vaporization ratio of the slurry.Increasing the oil gas temperature and reducing the slurry partial pressure could effectively slow down the coking speed in the RFCC disengager.According to the calculation results, a correlation was established to predict the vaporization ratio of the slurry under different operating conditions.
基金supported by a grant from "The 11th Five-year Plan of Scientific Research" of People’s Liberation Army of China (No. 06MA297)
文摘In this study, the vaporization ratio of the 2-μm laser in the prostatic tissue with benign prostatic hyperplasia was examined in vitro, to explore a technique to estimate the clearance rate of prostatic tissue during the transurethral vaporesection of the prostate. A total of 9 fresh prostatic tissue specimens were obtained by open surgery and the wet weight of the prostatic tissue were measured immediately after the sample collection. Under the simulated conditions of transurethral vaporesection of the prostate by 2-μm laser, each prostate gland was completely vaporesected into fragments with a diameter of less than 1.0 cm in vitro tissue were collected and measured. Then After the vaporesection, the whole fragments of prostatic the lost weight of prostatic tissue, the weight of the collected prostatic tissue and the ratio of the lost weight of prostatic tissue to the wet weight of the prostate glandular organ specimen were calculated. The correlation between the weight of collected prostatic tissue and the weight of the whole glandular organ was analyzed. All the experimental procedures were carried out by one operator. Wet weight of the prostatic gland specimen and the weight of the harvested prostatic tissues after the procedure were recorded. With respect to the wet weight of prostate gland specimen, the percentage of the weight of collected prostatic tissue was (34.45±1.51) %, and the percentage of the lost weight of prostatic tissue was (65.55±1.51)%. Satisfactory linear relationship was observed between the weight of collected prostatic tissue and the wet weight of prostate gland specimen [y=3.245x=6.475 (t=15.097, P=0.000)]. It is concluded that under the simulated conditions of transurethral vaporesection of the prostate by 2-μm laser, the vaporization ratio of prostatic tissue can be calculated on the basis of the weight of collected prostatic tissue, and thereby the clearance of prostatic tissue during the formal operation by 2-μm laser could be quantitatively determined.
文摘In the industrial production, the mixing of gas-liquid flow with vapor and gas-solid flow is a very common problem. In the process of the mixing, solid particle-clusters will form, and will have steady radii when the effect of the gathering of particles is balanced withthat of the breaking of particle-clusters. Then, the population distribution function of size of particles per unit length per unit volume is introduced, and its governingequation is derived on the analogy of the molecular kinetic theory. Finally, when the gas flow is very slow, the expression of steady average radius of particle-clusters is obtained.
文摘Biohydrogen production from synthetic waste, SW (model organic fraction of municipal solid waste) co-digested with liquid dairy manure (M) was tested in batch reactions to assess the effect of temperature and mixing ratio of the substrates. A 5 × 2 factorial design experiment was conducted. Synthetic waste: manure mixtures of 1:1, 2:1, 3:1, 1:0, 0:1 (volatile solids, VS, basis) were tested at 37 (T37) and 55 ℃ (T55) using thirty 1 L laboratory scale digesters. Total VS of each mixture was 50 g/L except SW:M 0:I treatment, where total VS was 27.4 g/L. Gas samples were taken daily to determine hydrogen production, and slurry samples taken before and after experimentation, were analyzed for volatile fatty acid (VFA) concentration, volatile solid (VS) degradation, ammonium nitrogen (NH4+-N) and pH. Hydrogen production (mL/g-VS fed) showed a significant two-factor interaction between incubation temperature and SW:M ratio (P 〈 0.001). Maximum production of 15.8 mL/g-VS (fed) was achieved in SW:M ratio of 3:1 at 55 ℃. Generally, hydrogen productions at thermophilic temperature (T55) were significantly higher than at mesophilic (T37) temperature for all treatments (P 〈 0.001) except for SW:M 1:0 and SW:M 0:1 treatments (P 〉 0.05). This study indicates that hydrogen production from co-digestion of synthetic waste and manure is dependent on incubation temperature and relative contribution of wastes in the mixture.
文摘The instrumentation, method and measurement results used for measurements of CO2 concentrations in surface air of Obninsk (55.1° N, 36.9° E, 183 m above the sea level) located at a distance of 105 km to the south-west of Moscow are presented. Proposed is a method of experimental data filtering allowing one to separate natural and anthropogenic variations of CO2 concentrations. It is shown that minimal concentrations of CO2 registered in Obninsk and at the continental stations of GAW WMO characterize not only the "regional background" but also coincide with the data from GAW WMO background stations located in the oceanic regions. In this connection, one can assume that the excess in measured CO2 concentration over its minimal values, making about 5-6 ppm, is connected with an anthropogenic emission, and the continent should be considered as an anthropogenic source of C02.
基金supported by the Ministry of Education of China (Grant PCSIRT)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)+2 种基金the National Natural Science Foundation of China (Grant No.31100359)the Natural Science Foundation of Jiangsu Province (Grant No.BK2011830)the Ningbo Planning Project of Science and Technology (Grant No.2012C50044)
文摘Methane (CH4) emissions estimated with the Intergovernmental Panel on Climate Change (IPCC) inventory method at the city and regional scale are subject to large uncertainties.In this study,we determined the CH4:CO2 emissions ratio for both Nanjing and the Yangtze River Delta (YRD),using the atmospheric CH4 and CO2 concentrations measured at a suburban site in Nanjing in the winter.The atmospheric estimate of the CH4:CO2 emissions ratio was in reasonable agreement with that calculated using the IPCC method for the YRD (within 20%),but was 200% greater for the municipality of Nanjing.The most likely reason for the discrepancy is that emissions from unmanaged landfills are omitted from the official statistics on garbage production.
基金Funded by the National Forestry Public Welfare Industry Major Projects of Scientific Research(No.201504502)National Natural Science Foundation of China(No.31200442)Supported by the Post Doctorate Research from the Ministry of Science and Technology of China(No.2014M550178)
文摘Starch/polylactic acid(PLA) composites were prepared by melt extrusion, with corn starch and PLA as raw materials, glycerol as the plasticizer. Effects of starch/PLA ratio on the interdependence of two-phase and other properties of the composites were studied. The combination of results of TGA with SEM indicated that the interdependence between starch and PLA was increased gradually as the starch/PLA ratio reduced. DSC results showed that the glass transition temperature(Tg), melting temperature(Tm) and degree of crystallinity of PLA in composites were increased gradually, whereas the cold crystallization temperature(Tc) was gradually decreased as the starch/PLA ratio reduced. The rheological properties of composites were closely related with the interdependence of two-phase, with reducing starch/PLA proportion, the interdependence was increased, and then the strain for storage modulus was firstl reduced and then gradually increased. Frequency scanning showed that the storage modulus and complex viscosity were decreased with reducing starch content. As the starch/PLA ratio reduced, the matrix phase PLA was increased, so that the strength of composites was increased gradually, whereas water absorption rate was decreased gradually.
基金Supported by the State Key Fundamental Research Program(2012CB720500)
文摘Operability problem of dividing wall column (DWC) raised by vapor split was investigated by numerically analyzing four cases defined by different compositions of a three-component mixture. DWCs were firstly designed for each case by optimizing the vapor split to the two sides of the dividing wall, and then their feasibilities and total annual costs in operation were evaluated against different vapor split ratios. The analysis on the operability of the DWC for four cases was made based on two scenarios: (1) vapor split is shifted by the vapor resistance difference between the column sections in the two sides of the dividing wall and (2) the feed composition is changed. It was demonstrated that the positioning of the dividing wall and the decision on the vapor split may affect significantly the operability of a DWC.
基金This work was financially supported by the China Geological Survey(Grant No.DD20160054)the National Natural Science Foundation of China(Grant No.U1407207)the National Key Research and Development Program of China(Grant No.2017YFC0602802).
文摘Tho Gudui geothermal field records the highest temperature at equivalent borehole depths among the lainland hydrothermal systems in China's Mainland.Located about 150 km southeast of Lhasa City,the capital of Tibet,the Gudui geothermal field belongs to the Sangri-Cuona rift belt,also known as the Sangri-Cuona geothermal belt,and is representative of the non-volcanic geothermal systems in the Himalayas.In this study,oxygen-18 and deuterium isotope compositions as well as 87Sr/86Sr ratios of water samples collected from the Gudui geothermal field were characterized to understand the origin and mixing processes of the geothermal fluids at Gudui.Hydrogen and oxygen isotope plots show both,deep and shallow reservoirs in the Gudui geothermal field.Deep geothermal fluids are the mixing product of magmatic and infiltrating snow-melt water.Calculations show that the magma fluid component of the deep geothermal fluids account for about 21.10%-24.04%;magma fluids lay also be a contributing source of lithium.The linear relationship of the 87Sr/86Sr isotopic ratio versus the 1/Sr plot indicates that shallow geothermal fluids form from the mixing of deep geothermal fluids with cold groundwater.Using a binary mixing model with deep geothermal fluid and cold groundwater as two end-members,the nixing ratios of the latter in most surface hot springs samples were calculated to be between 5% and 10%.Combined with basic geological characteristics,hydrogen and oxygen isotope characteristics,strontium concentration,87Sr/(86)Sr ratios,and the binary mixing model,we infer the 6 th-Class Reservoirs Evolution Conceptual Model(6-CRECM) for the Gudui geothermal system.This model represents an idealized summary of the characteristics of the Gudui geothermal field based on our comprehensive understanding of the origin and mixing processes of the geothermal fluid in Gudui.This study may aid in identifying the geothermal and geochemical origin of the Gudui high-temperature hydrothermal systems in remote Tibet of China,whose potential for geothermal development and utilization is enormous and untapped.
基金Funded by the National Natural Science Foundation of China(No.51908183)the Natural Science Foundation of Hebei Province(No.E2023202101)。
文摘The prediction model for mechanical properties of RAC was established through the Bayesian optimization-based Gaussian process regression(BO-GPR)method,where the input variables in BO-GPR model depend on the mix ratio of concrete.Then the compressive strength prediction model,the material cost,and environmental factors were simultaneously considered as objectives,while a multi-objective gray wolf optimization algorithm was developed for finding the optimal mix ratio.A total of 730 RAC datasets were used for training and testing the predication model,while the optimal design method for mix ratio was verified through RAC experiments.The experimental results show that the predicted,testing,and expected compressive strengths are nearly consistent,illustrating the effectiveness of the proposed method.
文摘A bound state formalism derived from a fermion-boson symmetric Lagrangian has been used to calculate the nucleon masses, the charge neutrality of the neutron, the magnetic moments and the electromagnetic form factor ratios μpGEp/GMpand μnGEn/GMn. A quantitative description is obtained, assuming a mixing of a scalar bound state of 3(f f¯)fstructure with its corresponding vector (f f¯)fstate (f indicating massless elementary fermions). Only a few parameters are needed, mainly fixed by energy and momentum conservation. The nucleon stability is explained by an extra binding in the confinement potential, negative for electric and positive for magnetic binding of the proton, and opposite for the neutron. The stronger electric extra binding of the proton allows a decay of the neutron to proton and electron.
文摘Some copolymers of 2,4-dichlorophenyl acrylate (2,4-DCPA) with styrene (St) of different teed compositions were prepared by tree radical polymerization technique using 2,2′-azobisisobutyronitrile (AIBN) as an initiator,and the copolymers were characterized by IR spectroscopy.The copolymer composition obtained by UV-spectra led to determination of reactivity ratio by employing Fineman-Ross (F-R) and Kelen-Tudos (K-T) methods.Average molecular weight,as well as intrinsic viscosity,was obtained by vapor pressu...
基金Supported by National Natural Science Foundation of China(71171003,71271003,and 11326121)Natural Science Foundation of Anhui Province(1508085MA02)+1 种基金Teaching Research Project of Anhui Province(2013jyxm111)Opening Project of Financial Engineering Research and Development Center of Anhui Polytechnic University(JRGCKF201502)
文摘This paper studies the insurer’s solvency ratio model in a class of mixed fractional Brownian motion(MFBM) market, where the prices of assets follow a Wick-It? stochastic differential equation driven by the MFBM, by the method of the stochastic calculus of the MFBM and the pricing formula of European call option for the MFBM, the explicit formula for the expected present value of shareholders’ terminal payoff is given. The model extends the existing results.
文摘An improved model to calculate the length of the mixing chamber of the ejector was proposed on the basis of the Fano flow model,and a method to optimize the structures of the mixing chamber and diffuser of the ejector was put forward.The accuracy of the model was verified by comparing the theoretical results calculated using the model to experimental data reported in literature.Variations in the length of the mixing chamber L_(m) and length of the diffuser L_(d) with respect to variations in the outlet temperature of the ejector T_(c),outlet pressure of the ejector p_(c),and the expansion ratio of the pressure of the primary flow to that of the secondary flow p_(g)/p_(e) were investigated.Moreover,variations in L_(m) and L_(d) with respect to variations in the ratio of the diameter of the throat of the motive nozzle to the diameter of the mixing chamber d_(g0)/d_(c3) and ratio of the outlet diameter of the diffuser to the diameter of themixing chamber d_(c)/d_(c3) were investigated.The distribution of flow fields in the ejector was simulated.Increasing L_(m) and d_(c3) reduced T_(c) and p_(c).Moreover,reducing p_(g)/p_(e) or d_(g0)/d_(c3) reduced T_(c) and p_(c).The length of the mixed section L_(m2),which was determined on the basis of the Fano flow model,increased as pg increased and decreased as d_(c3) increased.The mixing length L_(m1),which was considered the primary flow expansion,showed the opposite trend with that of L_(m2).Moreover,Ld increased as p_(g)/p_(e) and d_(c)/d_(c3) increased.When the value of d_(c) was 1.8 to 2.0 times as high as that of dc3,the semi-cone angle of the diffuser ranged between 6°and 12°.At a constant dc/dc3,decreasing T_(c) and pc increased Ld.
基金Project supported by the National High Technology Research and Development of China (Grant No.2009AA063006)the National Natural Science Foundation of China (Grant No. 40905010)the Special Project of Environmental Nonprofit Industry Research,China (Grant No. 201109007)
文摘A topographic target light scattering-differential optical absorption spectroscopy ('IbTaL-DOA~) system is de- veloped for measuring average concentrations along a known optical path and studying surface-near distributions of atmospheric trace gases. The telescope of the ToTaL-DOAS system points to targets which are located at known dis- tances from the measurement device and illuminated by sunlight. Average concentrations with high spatial resolution can be retrieved by receiving sunlight reflected from the targets, A filed measurement of NO2 concentration is performed with the ToTaL-DOAS system in Shijiazhuang in the autumn of 2011. The measurement data are compared with con- centrations measured by the point monitoring technique at the same site. The results show that the ToTaL-DOAS system is sensitive to the variation of NO2 concentrations along the optical path.
文摘In this paper, through the indoor free load swelling rate test, expansive soil in a section of a first- class highway reconstruction project in Yichang City was studied. It emphatically analyzed the interrelations among free load swelling rate, non-load time, the proportion of mixed sand and initial dry density. Experimen- tal studies have shown that: Free load swelling deformation is mainly divided into three stages of rapid expan- sion, slow expansion and final stability; when the initial dry density is constant, free load swelling rate of the weathered sand modified soil will reduce rapidly before they slow down with the increase of sand proportion, and weathered sand modified soil free load swelling rate is not sensitive to the large amount of sand mixed; in the same mixed sand ratio, weathered sand modified soil free load swelling rate increases rapidly with the in- crease of initial dry density, there is a good linear correlation between them. To take appropriate control of the initial dry density during the expansive soil subgrade construction helps to reduce its swelling deformation and ensures the stability of the embankment.
基金supported by the National Science and Technology Major Project(No.J2019-Ⅲ-0001-0044)。
文摘The air-turbo-rocket(ATR)engine is a promising propulsion plant for achieving numerous surface and air launched missile missions.The application of lobed mixer in the ATR combustor can promote the mixing of the fuelrich gas and the air,thus improving the engine performance significantly.The numerical simulation method was conducted to explore the effects of lobe peak-to-trough width ratio on mixing and combustion performance in ATR combustors.Results show that:For a given peak lobe width b1,the combustion efficiency and total pressure loss decrease with the increase of trough lobe width b2;For a given b2,the combustion efficiency and total pressure loss decrease with the increase of b1;The fan-type lobed mixer with smaller b2has a better effect on promoting the combustion efficiency in the region near the ATR combustor center line than that with a pair of parallel side walls.The total pressure recovery coefficient reaches more than 0.99 at the exit of combustor in nonreactive combustion while the total pressure loss reaches more than 4%in the reacting combustion.Compared with the mixing process,more than80%of the total pressure loss is caused during combustion.
文摘In recent years, the rationalization of concrete mix ratios which batches equal volumes of sand and gravel in building projects has been gaining grounds in the Cameroon construction industry. The main objective of this study is therefore to investigate if the concrete produced with rationalized mix ratio can be adopted as conventional mix ratio in terms of minimum required compression strength of concrete for buildings. Specifically this work compared the conventional mix ratio of 350 kg of cement: 400 liters of sand: 800 liters of gravel for a cubic meter and the rationalized batch of 350 kg of cement: 600 liters of sand: 600 liters of 5/15 gravel, 15/25 gravel and a combination of 5/15 + 15/25 gravel. Average compressive tests’results for both the conventional and the rationalized mix ratios were found to meet the minimum compressive strength of 65% at 7 days, 90% at 14 days and 99% at 28 days for gravel size combination 5/15 + 15/25. Single size gravel of 5/15 and 15/25 did not meet the minimum required compressive strength of 20 N/mm<sup>2</sup> for the rationalized mix ratio at 28 days curing based on the minimum compressive strength required, this study arrives at the conclusion that the equal volumes of sand and gravel mix ratio of 350 kg/m<sup>3</sup> of cement: 600 liters of sand: 600 liters of gravel mix ratio can be adopted as a conventional concrete mix ratio for gravel size 5/15 + 15/25.
基金Supported by the National Natural Science Foundation of China(No.29676003)and China Petro-chemical.Corporation.
文摘A new excess Gibbs free energy/equation of state type mixing 0rule was derived byremoving the infinite pressure boundary condition imposed by Wong and Sandler.The mixing rulewas extensively tested in terms of a comprehensive data base,consisting of 52 simple nonpolar-nonpolar,carbon dioxide containing,hydrocarbon-hydrocarbon,CFC,polar-polar,nonpolar-polarbinary and multicomponent systems.Focused on the complete predictive capability,a comparisonbetween the Wong-Sandler and the mixing rule proposed was conducted.The results indicate that thenew mixing rule is in general superior to the Wong-Sandler’s,and the binary interaction parameteras required by the latter is removed,which reduces computing effort and is reliable in predictions ofvapor-liquid equilibria from low pressures to high pressures.
文摘The multipole mixing ratios have been calculated by a2-ratio method, from levels of 93Mo(p, nγ) reaction. The branching ratios of such γ-transitions are used to calculate the total gamma widths. Besides, the transition strengths and probabilities have been calculated for γ-transitions from excited states whose life times have been reported previously. The results are found to be in general in good agreement with the previous results populated from the previous work.