In hot-dip galvanizing process, air jet wiping control is so crucial to decide the coating thickness and uni- formity of the zinc layer on the steel strip. The mathematical models developed predict the zinc coating th...In hot-dip galvanizing process, air jet wiping control is so crucial to decide the coating thickness and uni- formity of the zinc layer on the steel strip. The mathematical models developed predict the zinc coating thickness as a function of pressure and shear stress. The required pressure and shear stress profile on the strip surface were calcu- lated using regression analysis, and carried out using numerical simulation as FLUENT, a finite element analysis software. The influences of the outlet pressure, the nozzle to strip distance, the slot opening, the edge baffle plate, as well as the tilting angle of air knife were discussed. Combining with these results and regression analysis on the practical data, four first-order polynomial multi-parameter models were established for different targeted coating thicknesses with better regression coefficients. The validated model was used to carry out sensitivity analysis to de- termine the favorable controlling regime for the air jet wiping process.展开更多
In the continuous hot-dip galvanizing process, the gas-jet wiping is used to control the coating thickness of moving steel strip. The high speed gas-jet discharged from the nozzle slot impinges on the strip, and at th...In the continuous hot-dip galvanizing process, the gas-jet wiping is used to control the coating thickness of moving steel strip. The high speed gas-jet discharged from the nozzle slot impinges on the strip, and at this moment, wipes the liquid coating layer dragged by a moving strip. The coating thickness is generally influenced on the flow characteristics of wiping gas-jet such as the impinging pressure distribution, pressure gradient and shear stress distribution on the surface of strip. The flow characteristics of wiping gas-jet mentioned above depends upon considerably both the process operating conditions such as the nozzle pressure, nozzle-to-strip distance and line speed, and the geometry of gas-jet wiping apparatus such as the height of nozzle slot. In the present study, the effect of the geometry of nozzle on the coating thickness is investigated with the help of a computational fluid dynamics method. The height of nozzle slot is varied in the range of 0.6mm to 1.7mm. A finite volume method (FVM) is employed to solve two-dimensional, steady, compressible Navier-Stokes equations. Based upon the results obtained, the effect of the height of nozzle slot in the gas-jet wiping process is discussed in detail. The computational results show that for a given standoff distance between the nozzle to the strip, the effective height of nozzle slot exists in achieving thinner coating thickness.展开更多
Objective To investigate the lateralizing value of ictal face wiping(FW)in patients with refractory mesial temporal lobe epilepsy(MTLE).Methods Presurgical video types were retrospectively reviewed among 96 patients w...Objective To investigate the lateralizing value of ictal face wiping(FW)in patients with refractory mesial temporal lobe epilepsy(MTLE).Methods Presurgical video types were retrospectively reviewed among 96 patients who were seizure-free for at least 3 years after temporal lobectomy between 1997 and 2012.Attention展开更多
Wet wipes have become an indispensable part of modern life,offering convenience whether used for personal hygiene,baby care,or household cleaning.Wet wipes made of different materials each have their own characteristi...Wet wipes have become an indispensable part of modern life,offering convenience whether used for personal hygiene,baby care,or household cleaning.Wet wipes made of different materials each have their own characteristics,which not only directly affect the comfort and performance during use but are also closely related to environmental protection.Understanding their differences can help consumers make more informed choices—ones that meet daily needs while reducing the environmental burden.展开更多
Hydropol a water-soluble,marine-safe,non-toxic polymer,is set to revolutionize the manufacture of hygiene products,suchas wet wipes and sanitary pads by making them dissolvable,fulyflushable and preventing them from f...Hydropol a water-soluble,marine-safe,non-toxic polymer,is set to revolutionize the manufacture of hygiene products,suchas wet wipes and sanitary pads by making them dissolvable,fulyflushable and preventing them from forming fatbergs in sewers andreleasing harmful microplastics.This is thanks to the developmentof a revolutionary new dissolvable nonwoven material(flat,poroussheets that are made directly from separate filbres or from moltenplastic or plastic film)which uses Hydropol instead of conventionalplastics and helps prevent tonnes of plastic pollution from enteringthe environment.展开更多
This paper focuses on introducing the manufacture technology of 1 770 MPa galvanized steel wires for stay cables applied to domestic bridges.During the development practices of high strength galvanized wire for stay c...This paper focuses on introducing the manufacture technology of 1 770 MPa galvanized steel wires for stay cables applied to domestic bridges.During the development practices of high strength galvanized wire for stay cables used in Sutong Bridge,Baosteel has established three key technologies based on research of manufacture technology and technical innovation.The three key technologies are:"Double Tensioning + limiter die" process,"dominant process + fine adjustment" in integrated optimization technology and "three-level control" in hot dip galvanization.With these key technologies,Baosteel has produced 1 770 MPa galvanized wires for stay cable,which has high tensile strength,low relaxation and good torsion performances.展开更多
Objective: to explore the effective treatment of oral diseases through the change of nursing methods. Methods: 60 patients who were hospitalized in the Department of Stomatology of our hospital from January to August ...Objective: to explore the effective treatment of oral diseases through the change of nursing methods. Methods: 60 patients who were hospitalized in the Department of Stomatology of our hospital from January to August 2019 were randomly divided into three groups: A, B and C, with 20 patients in each group. Group A, B and C patients with oral diseases were given cotton ball wiping care, result classification and cotton ball combined care result classification. The rehabilitation effects of three groups of patients under different nursing measures were compared. Results: after two weeks of nursing, the effective rate of Group C was Group A and Group B, the data was statistically significant (P<0.05). After four weeks of nursing, the effective rates were Group C and Group B, Group A, the data were statistically significant (P<0.05). Conclusion: for patients with oral diseases, the cotton pad wiping method can achieve good nursing effect in the first two weeks. In the fourth week, the nursing effect of the classification of nursing results was significantly higher than that of oral wiping method. The nursing effect of wiping the oral cavity combined with the classification of nursing results is higher. Therefore, the nursing of oral diseases should adopt the method of cotton swab combined with the classification of nursing results.展开更多
In order to process video data efficiently,a video segmenting technique must be required.We propose a fast shot transition detecting algorithm directly on MPEG compressed video sequence.The algorithm can detect not on...In order to process video data efficiently,a video segmenting technique must be required.We propose a fast shot transition detecting algorithm directly on MPEG compressed video sequence.The algorithm can detect not only abrupt transition,but also gradual transition.The computing cost of the algorithm is low,because we directly use the type of macroblocks and motion vectors that MPEG compressed video provides.The result of experiment is rather well.展开更多
A new wipe transition detection approach was proposed. By analyzing the spatial-temporal characteristics of an ideal wipe production model, the concept of wipe transition strip (TS) was introduced. The macroblock type...A new wipe transition detection approach was proposed. By analyzing the spatial-temporal characteristics of an ideal wipe production model, the concept of wipe transition strip (TS) was introduced. The macroblock type information of P-frames is used to extract TS regions. An improved TS region accumulation technique is performed for detecting and verifying wipe transitions. The experimental results indicate that the proposed approach is capable of detecting various wipe transitions quickly and accurately.展开更多
AIM:To investigate the short-term effects of commercially available eyelid-cleaning wipes on film parameters.METHODS:This study enrolled 48 healthy participants aged 20-35y(both males and females).Clinical assessment ...AIM:To investigate the short-term effects of commercially available eyelid-cleaning wipes on film parameters.METHODS:This study enrolled 48 healthy participants aged 20-35y(both males and females).Clinical assessment included the Ocular Surface Disease Index(OSDI)questionnaire,non-invasive tear break-up time(NITBUT),tear meniscus height(TMH),and lipid layer pattern(LLP).Based on these initial results,participants were categorized as either non-dry eye or dry eye.Participants in each group were randomly allocated to either Blephaclean■or Systane■treatments.Changes in NITBUT,TMH,and LLP levels before and after lid wipe treatment were assessed.RESULTS:The dry eye group exhibited significantly higher OSDI scores and lower NITBUT and TMH levels than in the non-dry eye group(P<0.001).Following the application of eyelid wipes(Systane■wipes),dry eye subjects experienced a significant improvement in NITBUT levels(P=0.0014)compared to the non-dry eye individuals.Although the remaining participants showed a marginal increase in TMH and NITBUT levels,these changes did not achieve statistical significance(P>0.05).Similarly,the LLP levels were significantly improved with Systane■(P<0.001)post-treatment compared to individuals in the non-dry eye group.However,the dry eye subjects showed higher posttreatment LLP levels than the untreated group(P<0.02).CONCLUSION:The short-term effects of Systane®eyelid wipes on tear film parameters suggest their effectiveness in dry eye disease.Nonetheless,further exploration of their long-term impact is essential to justify their cost effectiveness and efficacy in treating both aqueous deficiency and evaporative dryness.展开更多
Objective:To analyze the effect of sanitary wipes and medical alcohol+gauze disinfection methods on the management and use of medical equipment in hospitals.Methods:From February 2023 to August 2023,80 anorectal surge...Objective:To analyze the effect of sanitary wipes and medical alcohol+gauze disinfection methods on the management and use of medical equipment in hospitals.Methods:From February 2023 to August 2023,80 anorectal surgery medical instruments and equipment were randomly sampled as observation samples,and they were grouped using the random number table method(40 instruments in each group).One group was managed with sanitary wipes and medical alcohol+gauze disinfection method(observation group),and the other group was managed with medical alcohol+gauze disinfection method(control group).The degree of contamination on the surface of instruments and equipment and the staff satisfaction of both groups was noted and compared.Results:After cleaning and disinfection,the relative luminescence luminosity(RLU)value of the surface contamination of the sample instruments and equipment decreased significantly(P<0.05);and after cleaning and disinfection,the relative luminescence luminosity(RLU)of the observation group’s instruments and equipment decreased significantly,and the value was lower than that of the control group,(P<0.05);the results of the nursing job satisfaction questionnaire showed that the scores of each survey item in the observation group were higher than those in the control group,(P<0.05).Conclusion:Integrating sanitary wipes and medical alcohol+gauze disinfection method into the management and use of medical equipment not only improves the disinfection of medical instruments but also improves the job satisfaction of nursing staff.Therefore,this method should be popularized.展开更多
In this paper we introduce and compare the definitions of cosmetics and regulatory status of wet wipes in Europe, United States, Canada, Australia and China. wet wipes used on human body are regulated as cosmetics in ...In this paper we introduce and compare the definitions of cosmetics and regulatory status of wet wipes in Europe, United States, Canada, Australia and China. wet wipes used on human body are regulated as cosmetics in Europe, United States, Canada and Australia, but as disposable hygiene products in China where there are no special provisions on the use of raw materials. Considering the cosmetic definition and industry development requirements, we suggest to include this type of wet wipes into cosmetic administration.展开更多
Synthetic antioxidants(SAs)are additives used to inhibit the oxidative degradation of materials.Due to their potential toxicity to humans,studies on identifying human exposure pathways of SAs are important.Herein,a br...Synthetic antioxidants(SAs)are additives used to inhibit the oxidative degradation of materials.Due to their potential toxicity to humans,studies on identifying human exposure pathways of SAs are important.Herein,a broad range of SAs were analyzed in hand wipe samples collected before and after basketball,with 37 SAs detected.Playing basketball significantly increases the concentration of SAs in human hands,with a median concentration ofΣSAs increased from 629 ng/wipe before playing basketball to 1.51×103 ng/wipe after playing basketball(p<0.05).Tris(2,4-di-tert-butylphenyl)phosphate(AO168O)was the predominant chemical,with the median concentration enhanced from 310 to 767 ng/wipe.The estimated daily exposure via the dermal exposure pathway of SAs was assessed to be 19.6 ng/kg bw/day after basketball,indicating minimal risks.Handwashing experiments demonstrated that most SAs can be removed from hands with tap water(removal efficiency:19.4−34.0%)and liquid soap(removal efficiency:32.3−81.8%)(p<0.05),while the removal efficiency of AO168O was low,contributing to its high residual levels in human hands.This is the first study to elucidate the dermal exposure to SAs via playing basketball,further indicating the importance of washing hands to reduce SA exposure.展开更多
To control the film thickness of zinc in the process of continuous hot-dip galvanizing, it is known from the early days that the gas wiping through an air knife is the most effective one. The gas wiping using in galva...To control the film thickness of zinc in the process of continuous hot-dip galvanizing, it is known from the early days that the gas wiping through an air knife is the most effective one. The gas wiping using in galvanizing process brings about a problem of splashing from the strip edge for a certain high speed of coating. So, in the present study, the effects of the deflection angle of Coanda nozzle on jet structure and the distribution of impinging pres- sure at the plate surface are investigated numerically and experimentally. In numerical analysis, the governing equations consisted of three-dimensional time dependent full Navier-Stokes equations, standard k-ε turbulence model to solve turbulent stTess and so on are employed. In experiment, 16 channel pressure scanning valve and 3-axis auto traversing unit are used to measure the impinging pressure at the strip surface. As a result, it is found that the smaller the deflection angle for the same nozzle slit of air knife is, the larger the impinging pressure is. To reduce the size of separation bubble and to enhance the cutting ability, it is recommendable to use an air knife with the Coanda nozzle.展开更多
A new separation method, wiped molecular distillation (WMD), was applied and experimental work was carried out to study the effect of operation parameters such as distillation temperature, pressure, feed flow rate, wi...A new separation method, wiped molecular distillation (WMD), was applied and experimental work was carried out to study the effect of operation parameters such as distillation temperature, pressure, feed flow rate, wiped speed and the separation stages on purifying the raw material containing 95% 3-hydroxypropionitrile (HPN). It was an excellent result that the mass concentration of HPN in the final product can be more than 99.5% under the optimistic operation conditions. The high purity cannot be achieved with normal separating method includ- ing rectification and extraction in practice. As for the raw material, a function of HPN purity in distillate was plotted with distillation temperature and pressure in experiment ranges. According to the experiment data obtained and the theory in molecular distillation, the distillation speed of HPN and separation efficiency were computed. It was concluded that the distillation speed of HPN and the separation efficiency were satisfying for industrial production.展开更多
Velocity field of evaporating liquid film in a wiped molecular distillator was simulated with a computational fluid dynamics (CFD) software, and two turbulent models treating near-wall flow were compared. Differences ...Velocity field of evaporating liquid film in a wiped molecular distillator was simulated with a computational fluid dynamics (CFD) software, and two turbulent models treating near-wall flow were compared. Differences between wiped and other molecular distillations were intro-duced to explain why turbulent model should be used in this simulation. Three assumptions were made in order to simplify simulating processes. In rotating coordinate system, fixed other settings, the above two turbulent models were used, and the volume of fluid (VOF) multiphase model was also applied to tracking the liquid-gas surface. Both of the simulating results are basically iden-tical with real situation and were compared in several aspects. It was concluded that both of the turbulent models are suitable in this simulation.展开更多
基金Sponsored by National Natural Science Foundation of China (50604006)National Development and Reform Commission of China (2009-354)
文摘In hot-dip galvanizing process, air jet wiping control is so crucial to decide the coating thickness and uni- formity of the zinc layer on the steel strip. The mathematical models developed predict the zinc coating thickness as a function of pressure and shear stress. The required pressure and shear stress profile on the strip surface were calcu- lated using regression analysis, and carried out using numerical simulation as FLUENT, a finite element analysis software. The influences of the outlet pressure, the nozzle to strip distance, the slot opening, the edge baffle plate, as well as the tilting angle of air knife were discussed. Combining with these results and regression analysis on the practical data, four first-order polynomial multi-parameter models were established for different targeted coating thicknesses with better regression coefficients. The validated model was used to carry out sensitivity analysis to de- termine the favorable controlling regime for the air jet wiping process.
文摘In the continuous hot-dip galvanizing process, the gas-jet wiping is used to control the coating thickness of moving steel strip. The high speed gas-jet discharged from the nozzle slot impinges on the strip, and at this moment, wipes the liquid coating layer dragged by a moving strip. The coating thickness is generally influenced on the flow characteristics of wiping gas-jet such as the impinging pressure distribution, pressure gradient and shear stress distribution on the surface of strip. The flow characteristics of wiping gas-jet mentioned above depends upon considerably both the process operating conditions such as the nozzle pressure, nozzle-to-strip distance and line speed, and the geometry of gas-jet wiping apparatus such as the height of nozzle slot. In the present study, the effect of the geometry of nozzle on the coating thickness is investigated with the help of a computational fluid dynamics method. The height of nozzle slot is varied in the range of 0.6mm to 1.7mm. A finite volume method (FVM) is employed to solve two-dimensional, steady, compressible Navier-Stokes equations. Based upon the results obtained, the effect of the height of nozzle slot in the gas-jet wiping process is discussed in detail. The computational results show that for a given standoff distance between the nozzle to the strip, the effective height of nozzle slot exists in achieving thinner coating thickness.
文摘Objective To investigate the lateralizing value of ictal face wiping(FW)in patients with refractory mesial temporal lobe epilepsy(MTLE).Methods Presurgical video types were retrospectively reviewed among 96 patients who were seizure-free for at least 3 years after temporal lobectomy between 1997 and 2012.Attention
文摘Wet wipes have become an indispensable part of modern life,offering convenience whether used for personal hygiene,baby care,or household cleaning.Wet wipes made of different materials each have their own characteristics,which not only directly affect the comfort and performance during use but are also closely related to environmental protection.Understanding their differences can help consumers make more informed choices—ones that meet daily needs while reducing the environmental burden.
文摘Hydropol a water-soluble,marine-safe,non-toxic polymer,is set to revolutionize the manufacture of hygiene products,suchas wet wipes and sanitary pads by making them dissolvable,fulyflushable and preventing them from forming fatbergs in sewers andreleasing harmful microplastics.This is thanks to the developmentof a revolutionary new dissolvable nonwoven material(flat,poroussheets that are made directly from separate filbres or from moltenplastic or plastic film)which uses Hydropol instead of conventionalplastics and helps prevent tonnes of plastic pollution from enteringthe environment.
基金National Science and Technology Planning Project(No.2006BAG04B02)
文摘This paper focuses on introducing the manufacture technology of 1 770 MPa galvanized steel wires for stay cables applied to domestic bridges.During the development practices of high strength galvanized wire for stay cables used in Sutong Bridge,Baosteel has established three key technologies based on research of manufacture technology and technical innovation.The three key technologies are:"Double Tensioning + limiter die" process,"dominant process + fine adjustment" in integrated optimization technology and "three-level control" in hot dip galvanization.With these key technologies,Baosteel has produced 1 770 MPa galvanized wires for stay cable,which has high tensile strength,low relaxation and good torsion performances.
文摘Objective: to explore the effective treatment of oral diseases through the change of nursing methods. Methods: 60 patients who were hospitalized in the Department of Stomatology of our hospital from January to August 2019 were randomly divided into three groups: A, B and C, with 20 patients in each group. Group A, B and C patients with oral diseases were given cotton ball wiping care, result classification and cotton ball combined care result classification. The rehabilitation effects of three groups of patients under different nursing measures were compared. Results: after two weeks of nursing, the effective rate of Group C was Group A and Group B, the data was statistically significant (P<0.05). After four weeks of nursing, the effective rates were Group C and Group B, Group A, the data were statistically significant (P<0.05). Conclusion: for patients with oral diseases, the cotton pad wiping method can achieve good nursing effect in the first two weeks. In the fourth week, the nursing effect of the classification of nursing results was significantly higher than that of oral wiping method. The nursing effect of wiping the oral cavity combined with the classification of nursing results is higher. Therefore, the nursing of oral diseases should adopt the method of cotton swab combined with the classification of nursing results.
基金Supported by the National Natural Science Foun-da1ion of China(60173045,F020204)
文摘In order to process video data efficiently,a video segmenting technique must be required.We propose a fast shot transition detecting algorithm directly on MPEG compressed video sequence.The algorithm can detect not only abrupt transition,but also gradual transition.The computing cost of the algorithm is low,because we directly use the type of macroblocks and motion vectors that MPEG compressed video provides.The result of experiment is rather well.
文摘A new wipe transition detection approach was proposed. By analyzing the spatial-temporal characteristics of an ideal wipe production model, the concept of wipe transition strip (TS) was introduced. The macroblock type information of P-frames is used to extract TS regions. An improved TS region accumulation technique is performed for detecting and verifying wipe transitions. The experimental results indicate that the proposed approach is capable of detecting various wipe transitions quickly and accurately.
文摘AIM:To investigate the short-term effects of commercially available eyelid-cleaning wipes on film parameters.METHODS:This study enrolled 48 healthy participants aged 20-35y(both males and females).Clinical assessment included the Ocular Surface Disease Index(OSDI)questionnaire,non-invasive tear break-up time(NITBUT),tear meniscus height(TMH),and lipid layer pattern(LLP).Based on these initial results,participants were categorized as either non-dry eye or dry eye.Participants in each group were randomly allocated to either Blephaclean■or Systane■treatments.Changes in NITBUT,TMH,and LLP levels before and after lid wipe treatment were assessed.RESULTS:The dry eye group exhibited significantly higher OSDI scores and lower NITBUT and TMH levels than in the non-dry eye group(P<0.001).Following the application of eyelid wipes(Systane■wipes),dry eye subjects experienced a significant improvement in NITBUT levels(P=0.0014)compared to the non-dry eye individuals.Although the remaining participants showed a marginal increase in TMH and NITBUT levels,these changes did not achieve statistical significance(P>0.05).Similarly,the LLP levels were significantly improved with Systane■(P<0.001)post-treatment compared to individuals in the non-dry eye group.However,the dry eye subjects showed higher posttreatment LLP levels than the untreated group(P<0.02).CONCLUSION:The short-term effects of Systane®eyelid wipes on tear film parameters suggest their effectiveness in dry eye disease.Nonetheless,further exploration of their long-term impact is essential to justify their cost effectiveness and efficacy in treating both aqueous deficiency and evaporative dryness.
文摘Objective:To analyze the effect of sanitary wipes and medical alcohol+gauze disinfection methods on the management and use of medical equipment in hospitals.Methods:From February 2023 to August 2023,80 anorectal surgery medical instruments and equipment were randomly sampled as observation samples,and they were grouped using the random number table method(40 instruments in each group).One group was managed with sanitary wipes and medical alcohol+gauze disinfection method(observation group),and the other group was managed with medical alcohol+gauze disinfection method(control group).The degree of contamination on the surface of instruments and equipment and the staff satisfaction of both groups was noted and compared.Results:After cleaning and disinfection,the relative luminescence luminosity(RLU)value of the surface contamination of the sample instruments and equipment decreased significantly(P<0.05);and after cleaning and disinfection,the relative luminescence luminosity(RLU)of the observation group’s instruments and equipment decreased significantly,and the value was lower than that of the control group,(P<0.05);the results of the nursing job satisfaction questionnaire showed that the scores of each survey item in the observation group were higher than those in the control group,(P<0.05).Conclusion:Integrating sanitary wipes and medical alcohol+gauze disinfection method into the management and use of medical equipment not only improves the disinfection of medical instruments but also improves the job satisfaction of nursing staff.Therefore,this method should be popularized.
文摘In this paper we introduce and compare the definitions of cosmetics and regulatory status of wet wipes in Europe, United States, Canada, Australia and China. wet wipes used on human body are regulated as cosmetics in Europe, United States, Canada and Australia, but as disposable hygiene products in China where there are no special provisions on the use of raw materials. Considering the cosmetic definition and industry development requirements, we suggest to include this type of wet wipes into cosmetic administration.
基金supported by the National Natural Science Foundation of China(NSFC 22376119,22206113)Shandong Provincial Natural Science Foundation,China(ZR2023JQ007)Taishan Scholars Project Special Fund(No.tsqn202211039).
文摘Synthetic antioxidants(SAs)are additives used to inhibit the oxidative degradation of materials.Due to their potential toxicity to humans,studies on identifying human exposure pathways of SAs are important.Herein,a broad range of SAs were analyzed in hand wipe samples collected before and after basketball,with 37 SAs detected.Playing basketball significantly increases the concentration of SAs in human hands,with a median concentration ofΣSAs increased from 629 ng/wipe before playing basketball to 1.51×103 ng/wipe after playing basketball(p<0.05).Tris(2,4-di-tert-butylphenyl)phosphate(AO168O)was the predominant chemical,with the median concentration enhanced from 310 to 767 ng/wipe.The estimated daily exposure via the dermal exposure pathway of SAs was assessed to be 19.6 ng/kg bw/day after basketball,indicating minimal risks.Handwashing experiments demonstrated that most SAs can be removed from hands with tap water(removal efficiency:19.4−34.0%)and liquid soap(removal efficiency:32.3−81.8%)(p<0.05),while the removal efficiency of AO168O was low,contributing to its high residual levels in human hands.This is the first study to elucidate the dermal exposure to SAs via playing basketball,further indicating the importance of washing hands to reduce SA exposure.
文摘To control the film thickness of zinc in the process of continuous hot-dip galvanizing, it is known from the early days that the gas wiping through an air knife is the most effective one. The gas wiping using in galvanizing process brings about a problem of splashing from the strip edge for a certain high speed of coating. So, in the present study, the effects of the deflection angle of Coanda nozzle on jet structure and the distribution of impinging pres- sure at the plate surface are investigated numerically and experimentally. In numerical analysis, the governing equations consisted of three-dimensional time dependent full Navier-Stokes equations, standard k-ε turbulence model to solve turbulent stTess and so on are employed. In experiment, 16 channel pressure scanning valve and 3-axis auto traversing unit are used to measure the impinging pressure at the strip surface. As a result, it is found that the smaller the deflection angle for the same nozzle slit of air knife is, the larger the impinging pressure is. To reduce the size of separation bubble and to enhance the cutting ability, it is recommendable to use an air knife with the Coanda nozzle.
文摘A new separation method, wiped molecular distillation (WMD), was applied and experimental work was carried out to study the effect of operation parameters such as distillation temperature, pressure, feed flow rate, wiped speed and the separation stages on purifying the raw material containing 95% 3-hydroxypropionitrile (HPN). It was an excellent result that the mass concentration of HPN in the final product can be more than 99.5% under the optimistic operation conditions. The high purity cannot be achieved with normal separating method includ- ing rectification and extraction in practice. As for the raw material, a function of HPN purity in distillate was plotted with distillation temperature and pressure in experiment ranges. According to the experiment data obtained and the theory in molecular distillation, the distillation speed of HPN and separation efficiency were computed. It was concluded that the distillation speed of HPN and the separation efficiency were satisfying for industrial production.
基金the National Natural Science Foundation of China(Grant No.20176037).
文摘Velocity field of evaporating liquid film in a wiped molecular distillator was simulated with a computational fluid dynamics (CFD) software, and two turbulent models treating near-wall flow were compared. Differences between wiped and other molecular distillations were intro-duced to explain why turbulent model should be used in this simulation. Three assumptions were made in order to simplify simulating processes. In rotating coordinate system, fixed other settings, the above two turbulent models were used, and the volume of fluid (VOF) multiphase model was also applied to tracking the liquid-gas surface. Both of the simulating results are basically iden-tical with real situation and were compared in several aspects. It was concluded that both of the turbulent models are suitable in this simulation.
