It is a complicated nonlinear controlling problem to conduct a two-dimensional trajectory correction of rockets.By establishing the aerodynamic correction force mathematical model of rockets on nose cone swinging,the ...It is a complicated nonlinear controlling problem to conduct a two-dimensional trajectory correction of rockets.By establishing the aerodynamic correction force mathematical model of rockets on nose cone swinging,the linear control is realized by the dynamic inverse nonlinear controlling theory and the three-time-scale separation method.The control ability and the simulation results are also tested and verified.The results show that the output responses of system track the expected curve well and the error is controlled in a given margin.The maximum correction is about±314 m in the lengthwise direction and±1 212 m in the crosswise direction from the moment of 5 s to the drop-point time when the angle of fire is 55°.Thus,based on the dynamic inverse control of feedback linearization,the trajectory correction capability of nose cone swinging can satisfy the requirements of two-dimensional ballistic correction,and the validity and effectiveness of the method are proved.展开更多
The swinging eyelid procedure is a versatile technique to approach orbital and periorbital surgical fields with less visible scar. Although mainly used in orbital surgeries, this procedure can also be used to expose t...The swinging eyelid procedure is a versatile technique to approach orbital and periorbital surgical fields with less visible scar. Although mainly used in orbital surgeries, this procedure can also be used to expose the zygomatic arch and periorbital areas. The swinging eyelid procedure, therefore, enables appropriate reduction of zygomaticomalar fracture under direct visualization. We used this technique for a 27 years old man with a displaced zygomaticomalar fracture that pushed on the lateral rectus muscle. Good functional and cosmetic results were obtained postoperatively without ocular motility impairment.展开更多
Consciousness is the gene of resistance that drives evolution by the evolutionary method-empathic Qualia, the subjective perturbation of “natural selection”, and the choice of which is not limited but stress-resista...Consciousness is the gene of resistance that drives evolution by the evolutionary method-empathic Qualia, the subjective perturbation of “natural selection”, and the choice of which is not limited but stress-resistant to mistakes. Looking into the mirror of ourselves, we bring evolution itself to the mirror, which, without blinking, looks with the eye of a frightened gazelle-incredulously-temptingly. Swinging it with a blow to a blow, taking a lunge and reflecting as the shine of slided comet, translating outrage into joy, the most closed resonant system-consciousness works. It is important not to miss any “punch”(knock/sound/word) that is thrown into your consciousness, so that the sound of the universe (and it is she who sends impulses of understanding) turns into improvisation of your own thinking-becoming a landing from “personal Idaho state”, so that the “muscles” of consciousness pumping iron-training do not sleep like a big earthworm that digested fast food (alimentary, cultured), being content with very little and chafing to empty, in order to work, interpreting what is happening near and around you, and comprehend creatively. The cohesion of eidos is so great that thought literally gains weight-you not only get tired quickly in the process of any “thinking”, but you feel that literally the world with weights hangs in your pockets, throwing a couple of blocks with houses and household on your shoulders. And this is all a consequence of the cohesion and microcoupling of all perceptions that revolve in your mind, touching them democratically: with fluids, resonating with waves of meanings, retransmitting impulses of images, and swaddling with the resulting introjections as by current-already according to Maxwell. Let us leave the God of God, art-skillful, and consciousness-seesaw swing of meanings.展开更多
San Francisco’s U.S. Court of Appeals building is the most ornate structure west of the Mississippi River.When it reopens in 1995, it may also be one of the safest.
This thesis focuses on a general lathe spindle,quantitatively analyzes the machining precision with spindle swinging in geometry way and derives a mathematical expression of machining errors at different swing frequen...This thesis focuses on a general lathe spindle,quantitatively analyzes the machining precision with spindle swinging in geometry way and derives a mathematical expression of machining errors at different swing frequencies. By applying MATLAB to simulate the work pieces＇ cross-section at different swing frequencies,taper is analyzed and variation law is summarized.展开更多
For six years,Music in the Summer Air(MISA)has been one of Shanghai’s most eclectic festivals,bridging contemporary classical with other mediums.With a theme of The Swinging Sixties,MISA 7 takes over the Shanghai Sym...For six years,Music in the Summer Air(MISA)has been one of Shanghai’s most eclectic festivals,bridging contemporary classical with other mediums.With a theme of The Swinging Sixties,MISA 7 takes over the Shanghai Symphony Orchestra Hall and Shanghai Urban Music Lawn from July 2-15.Here are the highlights.展开更多
Activity 1 Think about the following questions and write down your answers before reading the text.1.In your opinion,how could the swing sport be integrated into school physical education classes in different regions?...Activity 1 Think about the following questions and write down your answers before reading the text.1.In your opinion,how could the swing sport be integrated into school physical education classes in different regions?Do you think it's suitable for all schools?展开更多
In order to analysis the oxygen distribution in the adsorption bed during the hydrogen purification process from oxygen-containing feed gas and the safety of device operation, this article established a non-isothermal...In order to analysis the oxygen distribution in the adsorption bed during the hydrogen purification process from oxygen-containing feed gas and the safety of device operation, this article established a non-isothermal model for the pressure swing adsorption (PSA) separation process of 4-component (H_(2)/O_(2)/N_(2)/CH_(4)), and adopted a composite adsorption bed of activated carbon and molecular sieve. In this article, the oxygen distribution in the adsorption bed under different feed gas oxygen contents, different adsorption pressures, and different product hydrogen purity was studied for both vacuuming process and purging process. The study shows that during the process from the end of adsorption to the end of providing purging, the peak value of oxygen concentration in the adsorption bed gradually increases, with the highest value exceeding 30 times the oxygen content of the feed gas. Moreover, the concentration multiplier of oxygen in the adsorption bed increases with the increase of the adsorption pressure, decreases with the increase of the oxygen content in the feed gas, and increases with the decrease of the hydrogen product purity. When the oxygen content in the feed gas reaches 0.3% (vol), the peak value of oxygen concentration in the adsorption bed exceeds 10% (vol), which will make the front part of the oxygen concentration peak fall in an explosion limit range. As the decrease of product hydrogen content, the oxygen concentration peak in the adsorption bed will gradually move forward to the adsorption bed outlet, and even penetrate through the adsorption bed. And during the process of the oxygen concentration peak moving forward, the oxygen will enter the pipeline at the outlet of the adsorption bed, which will make the pipeline space of high-speed gas flow into an explosion range, bringing great risk to the device. The preferred option for safe operation of PSA for hydrogen purification from oxygen-containing feed gas is to deoxygenate the feed gas. When deoxygenation is not available, a lower adsorption pressure and a higher product hydrogen purity (greater than or equal to 99.9% (vol)) can be used to avoid the gas in the adsorption bed outlet pipeline being in the explosion range.展开更多
Swing nose crossings(SNXs)have been widely used in heavy haul railways to create a smoother load transfer and hence reduced impact load.However,the current design of SNXs hasn’t been fully examined under heavy haul o...Swing nose crossings(SNXs)have been widely used in heavy haul railways to create a smoother load transfer and hence reduced impact load.However,the current design of SNXs hasn’t been fully examined under heavy haul operating conditions.Additionally,maintenance guidelines for SNX wear-related issues in Australian heavy haul railways are relatively lacking.As such,this study aims to investigate the dynamic response of the wheel-rail contact and analyse the wear performance of an SNX currently used in Australian heavy haul railways.Dynamic implicit-explicit finite element analysis was conducted to simulate the wheel-rail contact along the SNX.The distribution of the wear intensity over the SNX was identified by using a local contact-based wear model.The influence of various scenarios on wear was also explored.The results verify the improved dynamic performance of the SNX,as the increased contact force after load transfer remains below 1.2 times the static load.The findings also indicate that the decrease in relative height and increase in nose rail inclination result in greater wear on the nose rail.Notably,the SNX considered in the current study exhibits better wear performance when used with moderately worn wheels.展开更多
Metal-Organic Frameworks(MOFs)have emerged as promising materials for gas adsorption and separation due to their exceptional surface area,tunable porosity,and versatility in functionalization.This paper explores the m...Metal-Organic Frameworks(MOFs)have emerged as promising materials for gas adsorption and separation due to their exceptional surface area,tunable porosity,and versatility in functionalization.This paper explores the mechanisms of gas adsorption in MOFs,including physical adsorption,chemisorption,and synergistic effects,which contribute to their efficiency in capturing and separating gases.The applications of MOFs in key areas such as carbon dioxide capture,hydrogen storage,natural gas separation,and air purification are discussed,highlighting their potential to address pressing environmental and energy challenges.Additionally,the use of MOFs in selective gas separation,membranes,and adsorption-based technologies like Pressure Swing Adsorption(PSA)and Vacuum Swing Adsorption(VSA)is explored,emphasizing their advantages over traditional materials.Despite challenges related to scalability,stability,and cost,MOFs hold great promise for advancing gas separation technologies in the near future,offering more efficient,sustainable,and environmentally friendly solutions.展开更多
How multi-unmanned aerial vehicles(UAVs)carrying a payload pass an obstacle-dense environment is practically important.Up to now,there have been few results on safe motion planning for the multi-UAVs cooperative trans...How multi-unmanned aerial vehicles(UAVs)carrying a payload pass an obstacle-dense environment is practically important.Up to now,there have been few results on safe motion planning for the multi-UAVs cooperative transportation system(CTS)to pass through such an environment.The prob-lem is challenging because it is difficult to analyze and explicitly take into account the swing motion of the payload in planning.In this paper,a modeling method of virtual tube is proposed by fus-ing the advantages of the existing modeling algorithm for regu-lar virtual tube and the expansion environment method.The pro-posed method can not only generate a safe and smooth tube for UAVs,but also ensure the payload stays away from the dense obstacles.Simulation results show the effectiveness of the method and the safety of the planned tube.展开更多
In this study,a novel synergistic swing energy-regenerative hybrid system(SSEHS)for excavators with a large inertia slewing platform is constructed.With the SSEHS,the pressure boosting and output energy synergy of mul...In this study,a novel synergistic swing energy-regenerative hybrid system(SSEHS)for excavators with a large inertia slewing platform is constructed.With the SSEHS,the pressure boosting and output energy synergy of multiple energy sources can be realized,while the swing braking energy can be recovered and used by means of hydraulic energy.Additionally,considering the system constraints and comprehensive optimization conditions of energy efficiency and dynamic characteristics,an improved multi-objective particle swarm optimization(IMOPSO)combined with an adaptive grid is proposed for parameter optimization of the SSEHS.Meanwhile,a parameter rule-based control strategy is designed,which can switch to a reasonable working mode according to the real-time state.Finally,a physical prototype of a 50-t excavator and its AMESim model is established.The semi-simulation and semi-experiment results demonstrate that compared with a conventional swing system,energy consumption under the 90°rotation condition could be reduced by about 51.4%in the SSEHS before parameter optimization,while the energy-saving efficiency is improved by another 13.2%after parameter optimization.This confirms the effectiveness of the SSEHS and the IMOPSO parameter optimization method proposed in this paper.The IMOPSO algorithm is universal and can be used for parameter matching and optimization of hybrid power systems.展开更多
This study delves into the optimization of the methanol-vinyl acetate(VAC)azeotrope separation process via pressure swing distillation(PSD),along with an evaluation of its energy-saving potential.The methanol-VAC syst...This study delves into the optimization of the methanol-vinyl acetate(VAC)azeotrope separation process via pressure swing distillation(PSD),along with an evaluation of its energy-saving potential.The methanol-VAC system,a polar azeotro pe highly susceptible to pressure variations,presents notable separation complexities in polyvinyl alcohol production.Aspen Plus simulations were utilized to assess the feasibility of PSD,with particular emphasis on critical process parameters such as the number of theoretical plates,feed position,reflux ratio,and sidestream extraction location.The results indicate that PSD demonstrates remarkable efficacy in separating methanol and VAC,achieving purities of 99.88%and 99.73%respectively.When compared to extractive distillation,PSD achieves a reduction of 9.07 t·h^(-1)in steam consumption and minimizes wastewater generation by 20.77 t·h^(-1).Furthermore,the economic assessment reveals a 7.91%decrease in the total annual cost associated with PSD.This study not only provides theoretical insights but also offers practical guidance for the design of energyefficient and sustainable separation processes.Future research will focus on extending the analysis to encompass multi-pressure scenarios,further enhancing the applicability and robustness of the findings.展开更多
A mathematical model for simulating concentric-bed and other components of molecular sieve oxygen concentrator is established. In the model, the binary Langmuir equilibrium adsorption equation is adopted to describe t...A mathematical model for simulating concentric-bed and other components of molecular sieve oxygen concentrator is established. In the model, the binary Langmuir equilibrium adsorption equation is adopted to describe the adsorption performance of the adsorbent, the linear driving force (LDF) model is used to describe the mass transfer rate, and the thermal effect during adsorption is considered. The finite difference method is used in simulation and comparison. Numerical results have a reasonable agreement with the experimental research.展开更多
An LES simulation of flow over an accumulator unit of an underwater compressed air energy storage facility was conducted. The accumulator unit consists of three touching underwater balloons arranged in a floral config...An LES simulation of flow over an accumulator unit of an underwater compressed air energy storage facility was conducted. The accumulator unit consists of three touching underwater balloons arranged in a floral configuration. The structure of the flow was examined via three dimensional iso surfaces of the Q criterion. Vortical cores were observed on the leeward surface of the balloons. The swirling tube flows generated by these vortical cores were depicted through three dimensional path lines. The flow dynamics were visualized via time series snapshots of two dimensional vorticity contours perpendicular to the flow direction; revealing the turbulent swinging motions of the aforementioned shedding-swirling tube flows. The time history of the hydrodynamic loading was presented in terms of lift and drag coefficients. Drag coefficient of each individual balloon in the floral configuration was smaller than that of a single balloon. It was found that the total drag coefficient of the floral unit of three touching balloons, i.e. summation of the drag coefficients of the balloons, is not too much larger than that of a single balloon whereas it provides three times the storage capacity. In addition to its practical significance in designing appropriate foundation and supports, the instantaneous hydrodynamic loading was used to determine the frequency of the turbulent swirling-swinging motions of the shedding vortex tubes; the Strouhal number was found to be larger than that of a single sphere at the same Reynolds number.展开更多
In this paper modelling of the translational motion of transportation rail-guided cart with rope suspended payload is considered. The linearly moving cart,driven by a travel mechanism,is modelled as a discrete six deg...In this paper modelling of the translational motion of transportation rail-guided cart with rope suspended payload is considered. The linearly moving cart,driven by a travel mechanism,is modelled as a discrete six degrees of freedom (DOF) dynamic system. The hoisting mechanism for lowering and lifting the payload is considered and is included in the dynamic model as one DOF system. Differential equations of motion of the cart elements are derived using Lagrangian dynamics and are solved for a set of real-life constant parameters of the cart. A two-sided interaction was observed between the swinging payload and the travel mechanism. Results for kinematical and force parameters of the system are obtained. A verification of the proposed model was conducted.展开更多
基金Project(9140A05030109HK01)supported by Equipment Pre-research Foundation,China
文摘It is a complicated nonlinear controlling problem to conduct a two-dimensional trajectory correction of rockets.By establishing the aerodynamic correction force mathematical model of rockets on nose cone swinging,the linear control is realized by the dynamic inverse nonlinear controlling theory and the three-time-scale separation method.The control ability and the simulation results are also tested and verified.The results show that the output responses of system track the expected curve well and the error is controlled in a given margin.The maximum correction is about±314 m in the lengthwise direction and±1 212 m in the crosswise direction from the moment of 5 s to the drop-point time when the angle of fire is 55°.Thus,based on the dynamic inverse control of feedback linearization,the trajectory correction capability of nose cone swinging can satisfy the requirements of two-dimensional ballistic correction,and the validity and effectiveness of the method are proved.
文摘The swinging eyelid procedure is a versatile technique to approach orbital and periorbital surgical fields with less visible scar. Although mainly used in orbital surgeries, this procedure can also be used to expose the zygomatic arch and periorbital areas. The swinging eyelid procedure, therefore, enables appropriate reduction of zygomaticomalar fracture under direct visualization. We used this technique for a 27 years old man with a displaced zygomaticomalar fracture that pushed on the lateral rectus muscle. Good functional and cosmetic results were obtained postoperatively without ocular motility impairment.
文摘Consciousness is the gene of resistance that drives evolution by the evolutionary method-empathic Qualia, the subjective perturbation of “natural selection”, and the choice of which is not limited but stress-resistant to mistakes. Looking into the mirror of ourselves, we bring evolution itself to the mirror, which, without blinking, looks with the eye of a frightened gazelle-incredulously-temptingly. Swinging it with a blow to a blow, taking a lunge and reflecting as the shine of slided comet, translating outrage into joy, the most closed resonant system-consciousness works. It is important not to miss any “punch”(knock/sound/word) that is thrown into your consciousness, so that the sound of the universe (and it is she who sends impulses of understanding) turns into improvisation of your own thinking-becoming a landing from “personal Idaho state”, so that the “muscles” of consciousness pumping iron-training do not sleep like a big earthworm that digested fast food (alimentary, cultured), being content with very little and chafing to empty, in order to work, interpreting what is happening near and around you, and comprehend creatively. The cohesion of eidos is so great that thought literally gains weight-you not only get tired quickly in the process of any “thinking”, but you feel that literally the world with weights hangs in your pockets, throwing a couple of blocks with houses and household on your shoulders. And this is all a consequence of the cohesion and microcoupling of all perceptions that revolve in your mind, touching them democratically: with fluids, resonating with waves of meanings, retransmitting impulses of images, and swaddling with the resulting introjections as by current-already according to Maxwell. Let us leave the God of God, art-skillful, and consciousness-seesaw swing of meanings.
文摘San Francisco’s U.S. Court of Appeals building is the most ornate structure west of the Mississippi River.When it reopens in 1995, it may also be one of the safest.
文摘This thesis focuses on a general lathe spindle,quantitatively analyzes the machining precision with spindle swinging in geometry way and derives a mathematical expression of machining errors at different swing frequencies. By applying MATLAB to simulate the work pieces＇ cross-section at different swing frequencies,taper is analyzed and variation law is summarized.
文摘For six years,Music in the Summer Air(MISA)has been one of Shanghai’s most eclectic festivals,bridging contemporary classical with other mediums.With a theme of The Swinging Sixties,MISA 7 takes over the Shanghai Symphony Orchestra Hall and Shanghai Urban Music Lawn from July 2-15.Here are the highlights.
文摘Activity 1 Think about the following questions and write down your answers before reading the text.1.In your opinion,how could the swing sport be integrated into school physical education classes in different regions?Do you think it's suitable for all schools?
基金support provided by the Sichuan Province Science and Technology Achievement Transformation Project (2023ZHCG0063).
文摘In order to analysis the oxygen distribution in the adsorption bed during the hydrogen purification process from oxygen-containing feed gas and the safety of device operation, this article established a non-isothermal model for the pressure swing adsorption (PSA) separation process of 4-component (H_(2)/O_(2)/N_(2)/CH_(4)), and adopted a composite adsorption bed of activated carbon and molecular sieve. In this article, the oxygen distribution in the adsorption bed under different feed gas oxygen contents, different adsorption pressures, and different product hydrogen purity was studied for both vacuuming process and purging process. The study shows that during the process from the end of adsorption to the end of providing purging, the peak value of oxygen concentration in the adsorption bed gradually increases, with the highest value exceeding 30 times the oxygen content of the feed gas. Moreover, the concentration multiplier of oxygen in the adsorption bed increases with the increase of the adsorption pressure, decreases with the increase of the oxygen content in the feed gas, and increases with the decrease of the hydrogen product purity. When the oxygen content in the feed gas reaches 0.3% (vol), the peak value of oxygen concentration in the adsorption bed exceeds 10% (vol), which will make the front part of the oxygen concentration peak fall in an explosion limit range. As the decrease of product hydrogen content, the oxygen concentration peak in the adsorption bed will gradually move forward to the adsorption bed outlet, and even penetrate through the adsorption bed. And during the process of the oxygen concentration peak moving forward, the oxygen will enter the pipeline at the outlet of the adsorption bed, which will make the pipeline space of high-speed gas flow into an explosion range, bringing great risk to the device. The preferred option for safe operation of PSA for hydrogen purification from oxygen-containing feed gas is to deoxygenate the feed gas. When deoxygenation is not available, a lower adsorption pressure and a higher product hydrogen purity (greater than or equal to 99.9% (vol)) can be used to avoid the gas in the adsorption bed outlet pipeline being in the explosion range.
基金supported by Australia Research Council through the Linkage Project(Grant No.LP200100110).
文摘Swing nose crossings(SNXs)have been widely used in heavy haul railways to create a smoother load transfer and hence reduced impact load.However,the current design of SNXs hasn’t been fully examined under heavy haul operating conditions.Additionally,maintenance guidelines for SNX wear-related issues in Australian heavy haul railways are relatively lacking.As such,this study aims to investigate the dynamic response of the wheel-rail contact and analyse the wear performance of an SNX currently used in Australian heavy haul railways.Dynamic implicit-explicit finite element analysis was conducted to simulate the wheel-rail contact along the SNX.The distribution of the wear intensity over the SNX was identified by using a local contact-based wear model.The influence of various scenarios on wear was also explored.The results verify the improved dynamic performance of the SNX,as the increased contact force after load transfer remains below 1.2 times the static load.The findings also indicate that the decrease in relative height and increase in nose rail inclination result in greater wear on the nose rail.Notably,the SNX considered in the current study exhibits better wear performance when used with moderately worn wheels.
文摘Metal-Organic Frameworks(MOFs)have emerged as promising materials for gas adsorption and separation due to their exceptional surface area,tunable porosity,and versatility in functionalization.This paper explores the mechanisms of gas adsorption in MOFs,including physical adsorption,chemisorption,and synergistic effects,which contribute to their efficiency in capturing and separating gases.The applications of MOFs in key areas such as carbon dioxide capture,hydrogen storage,natural gas separation,and air purification are discussed,highlighting their potential to address pressing environmental and energy challenges.Additionally,the use of MOFs in selective gas separation,membranes,and adsorption-based technologies like Pressure Swing Adsorption(PSA)and Vacuum Swing Adsorption(VSA)is explored,emphasizing their advantages over traditional materials.Despite challenges related to scalability,stability,and cost,MOFs hold great promise for advancing gas separation technologies in the near future,offering more efficient,sustainable,and environmentally friendly solutions.
基金supported by the National Natural Science Foundation of China(6237338661973327).
文摘How multi-unmanned aerial vehicles(UAVs)carrying a payload pass an obstacle-dense environment is practically important.Up to now,there have been few results on safe motion planning for the multi-UAVs cooperative transportation system(CTS)to pass through such an environment.The prob-lem is challenging because it is difficult to analyze and explicitly take into account the swing motion of the payload in planning.In this paper,a modeling method of virtual tube is proposed by fus-ing the advantages of the existing modeling algorithm for regu-lar virtual tube and the expansion environment method.The pro-posed method can not only generate a safe and smooth tube for UAVs,but also ensure the payload stays away from the dense obstacles.Simulation results show the effectiveness of the method and the safety of the planned tube.
基金supported by the Changsha Major Science and Technology Plan Project,China(No.kq2207002)the Natural Science Foundation of Hunan Province(No.2023JJ40720)the Postgraduate Innovative Project of Central South University,China(No.2022XQLH058)。
文摘In this study,a novel synergistic swing energy-regenerative hybrid system(SSEHS)for excavators with a large inertia slewing platform is constructed.With the SSEHS,the pressure boosting and output energy synergy of multiple energy sources can be realized,while the swing braking energy can be recovered and used by means of hydraulic energy.Additionally,considering the system constraints and comprehensive optimization conditions of energy efficiency and dynamic characteristics,an improved multi-objective particle swarm optimization(IMOPSO)combined with an adaptive grid is proposed for parameter optimization of the SSEHS.Meanwhile,a parameter rule-based control strategy is designed,which can switch to a reasonable working mode according to the real-time state.Finally,a physical prototype of a 50-t excavator and its AMESim model is established.The semi-simulation and semi-experiment results demonstrate that compared with a conventional swing system,energy consumption under the 90°rotation condition could be reduced by about 51.4%in the SSEHS before parameter optimization,while the energy-saving efficiency is improved by another 13.2%after parameter optimization.This confirms the effectiveness of the SSEHS and the IMOPSO parameter optimization method proposed in this paper.The IMOPSO algorithm is universal and can be used for parameter matching and optimization of hybrid power systems.
基金financial support from the National Key Research and Development Program of China(2022YFC2106300)the National Nature Science Foundation of China(U2267226)。
文摘This study delves into the optimization of the methanol-vinyl acetate(VAC)azeotrope separation process via pressure swing distillation(PSD),along with an evaluation of its energy-saving potential.The methanol-VAC system,a polar azeotro pe highly susceptible to pressure variations,presents notable separation complexities in polyvinyl alcohol production.Aspen Plus simulations were utilized to assess the feasibility of PSD,with particular emphasis on critical process parameters such as the number of theoretical plates,feed position,reflux ratio,and sidestream extraction location.The results indicate that PSD demonstrates remarkable efficacy in separating methanol and VAC,achieving purities of 99.88%and 99.73%respectively.When compared to extractive distillation,PSD achieves a reduction of 9.07 t·h^(-1)in steam consumption and minimizes wastewater generation by 20.77 t·h^(-1).Furthermore,the economic assessment reveals a 7.91%decrease in the total annual cost associated with PSD.This study not only provides theoretical insights but also offers practical guidance for the design of energyefficient and sustainable separation processes.Future research will focus on extending the analysis to encompass multi-pressure scenarios,further enhancing the applicability and robustness of the findings.
文摘A mathematical model for simulating concentric-bed and other components of molecular sieve oxygen concentrator is established. In the model, the binary Langmuir equilibrium adsorption equation is adopted to describe the adsorption performance of the adsorbent, the linear driving force (LDF) model is used to describe the mass transfer rate, and the thermal effect during adsorption is considered. The finite difference method is used in simulation and comparison. Numerical results have a reasonable agreement with the experimental research.
文摘An LES simulation of flow over an accumulator unit of an underwater compressed air energy storage facility was conducted. The accumulator unit consists of three touching underwater balloons arranged in a floral configuration. The structure of the flow was examined via three dimensional iso surfaces of the Q criterion. Vortical cores were observed on the leeward surface of the balloons. The swirling tube flows generated by these vortical cores were depicted through three dimensional path lines. The flow dynamics were visualized via time series snapshots of two dimensional vorticity contours perpendicular to the flow direction; revealing the turbulent swinging motions of the aforementioned shedding-swirling tube flows. The time history of the hydrodynamic loading was presented in terms of lift and drag coefficients. Drag coefficient of each individual balloon in the floral configuration was smaller than that of a single balloon. It was found that the total drag coefficient of the floral unit of three touching balloons, i.e. summation of the drag coefficients of the balloons, is not too much larger than that of a single balloon whereas it provides three times the storage capacity. In addition to its practical significance in designing appropriate foundation and supports, the instantaneous hydrodynamic loading was used to determine the frequency of the turbulent swirling-swinging motions of the shedding vortex tubes; the Strouhal number was found to be larger than that of a single sphere at the same Reynolds number.
文摘In this paper modelling of the translational motion of transportation rail-guided cart with rope suspended payload is considered. The linearly moving cart,driven by a travel mechanism,is modelled as a discrete six degrees of freedom (DOF) dynamic system. The hoisting mechanism for lowering and lifting the payload is considered and is included in the dynamic model as one DOF system. Differential equations of motion of the cart elements are derived using Lagrangian dynamics and are solved for a set of real-life constant parameters of the cart. A two-sided interaction was observed between the swinging payload and the travel mechanism. Results for kinematical and force parameters of the system are obtained. A verification of the proposed model was conducted.
