The Arctic region is experiencing accelerated sea ice melt and increased iceberg detachment from glaciers due to climate change.These drifting icebergs present a risk and engineering challenge for subsea installations...The Arctic region is experiencing accelerated sea ice melt and increased iceberg detachment from glaciers due to climate change.These drifting icebergs present a risk and engineering challenge for subsea installations traversing shallow waters,where ice-berg keels may reach the seabed,potentially damaging subsea structures.Consequently,costly and time-intensive iceberg manage-ment operations,such as towing and rerouting,are undertaken to safeguard subsea and offshore infrastructure.This study,therefore,explores the application of extra tree regression(ETR)as a robust solution for estimating iceberg draft,particularly in the preliminary phases of decision-making for iceberg management projects.Nine ETR models were developed using parameters influencing iceberg draft.Subsequent analyses identified the most effective models and significant input variables.Uncertainty analysis revealed that the superior ETR model tended to overestimate iceberg drafts;however,it achieved the highest precision,correlation,and simplicity in estimation.Comparison with decision tree regression,random forest regression,and empirical methods confirmed the superior perfor-mance of ETR in predicting iceberg drafts.展开更多
In order to study influences of geometric parameters on the T-shaped components local loading process, a new mathematical model considering the fillet radius and draft angle was established by using the slab method. T...In order to study influences of geometric parameters on the T-shaped components local loading process, a new mathematical model considering the fillet radius and draft angle was established by using the slab method. The results obtained by the mathematical model agree with the data form experiment and numerical simulation, and the results are closer to the experimental and simulation results. The influence of draft angle may be neglected under the forming conditions used. The influence of fillet radius is notable, especially in the case that the ratio of fillet radius to rib width is less than 0.75.展开更多
To study the draft sensation distribution of an air jet supply system in a large space building in summer,experiments are conducted in a large laboratory.The temperature,velocity and draft sensation distributions at a...To study the draft sensation distribution of an air jet supply system in a large space building in summer,experiments are conducted in a large laboratory.The temperature,velocity and draft sensation distributions at a nozzle height of 4 m in the occupied zone are obtained.Then,the numerical simulation under the test condition is carried out by the computational fluid dynamics（CFD）method.The calculation results of the indoor vertical temperature and the draft sensation distribution are validated by the test data.Simulations with different nozzle heights are conducted.The satisfactory air supply condition is determined by analyzing the draft sensations and the temperatures in the occupied zone under three conditions.The simulation results show that the optimal draft sensation distribution and the uniform temperature and velocity fields can be obtained at a nozzle height of 5 m.展开更多
This study set out to investigate the effect of operational parameters (i.e. ripping depth and operational speed) during a ripping operation on the draft requirement during ripping in a sandy-clay soil. Field experime...This study set out to investigate the effect of operational parameters (i.e. ripping depth and operational speed) during a ripping operation on the draft requirement during ripping in a sandy-clay soil. Field experiments, laboratory tests and numerical modelling techniques were utilised to observe how the draft force varied with changing values of the operational parameters. The discrete element method in the EDEM Academic<sup>TM</sup> software platform was employed to model the soil en-masse to obtain a virtual experimentation platform on which different treatments combing different settings of the operational parameters were investigated. Statistical methods, including ANOVA, regression analysis and the student t-test were applied to establish the significance of the effect of the operational parameters on the draft requirement;statistical analysis revealed that the draft increased linearly with the ripping depth and operating speed suggesting that they are directly proportional. Lower values of the ripping depth and operating speed were found to give the minimum amount of the draft requirement.展开更多
The mechanism of the staple yarn's drafting waves during roller drafting is analyzed in this paper.It's concluded that the dynamic friction coefficient is greater than the static friction coefficient on the fr...The mechanism of the staple yarn's drafting waves during roller drafting is analyzed in this paper.It's concluded that the dynamic friction coefficient is greater than the static friction coefficient on the friction behavior of fibers,and the difference is largely responsible for the "stick-slip" motion of fibers which causes the drafting waves during drafting.In this paper,it's expected that when a high frequency undulating wave is imposed on the fiber strand in the drafting zone of roller system,the friction among fibers is dominated by the dynamic friction rather than the static friction,and thus the "stick-slip" motion will be eliminated.As a result,the fiber binding effect causing drafting waves can be significantly reduced.This hypothesis is verified by an experiment,and it can be applied in developing new spinning drafting device.展开更多
The crux of this paper is based on the pattern drafting of woven fabrics. It is necessary because many textile designers or weavers cannot generate and develop their personal pattern drafts for weaving. It is obvious ...The crux of this paper is based on the pattern drafting of woven fabrics. It is necessary because many textile designers or weavers cannot generate and develop their personal pattern drafts for weaving. It is obvious that they mainly copy other people’s designs to weave. This paper therefore has provided an easy and simple way to learn, focus and develop their original designs to weave. The practical production method is used to create, generate and develop the pattern drafts in this paper. The paper focuses on the components of the pattern draft which will surely help to forecast and have a view of the appearance of the design before it is woven on the cloth. In conclusion, the weaver will be able to record and document his/her original works for posterity.展开更多
Overview Heats stroke(HS)is severe sunstroke caused by a rapid increase in one’s core temperature in excess of 40°C from exposure to a hot and humid environment.HS is accompanied by serious clinical syndromes th...Overview Heats stroke(HS)is severe sunstroke caused by a rapid increase in one’s core temperature in excess of 40°C from exposure to a hot and humid environment.HS is accompanied by serious clinical syndromes that damage multiple organ systems.h ese syndromes include burning skin and impaired awareness,such as delir ium,conv ul sions,and loss of consciousness.Exertional heat stroke(EHS)is caused by a rapid increase in one’s core temperature in excess of 40°C from high intensity展开更多
The value of form factor k at different drafts is important in predicting full-scale total resistance and speed for different types of ships. In the ITTC community, most organizations predict form factor k using a low...The value of form factor k at different drafts is important in predicting full-scale total resistance and speed for different types of ships. In the ITTC community, most organizations predict form factor k using a low-speed model test. However, this method is problematic for ships with bulbous bows and transom. In this article, a Computational Fluid Dynamics(CFD)-based method is introduced to obtain k for different type of ships at different drafts, and a comparison is made between the CFD method and the model test. The results show that the CFD method produces reasonable k values. A grid generating method and turbulence model are briefly discussed in the context of obtaining a consistent k using CFD.展开更多
A method for analyzing reflection and transmission of ocean waves from a semi-infinlte elastic plate with a draft is developed. The relation of energy conservation for plates with three different edge conditions （ fr...A method for analyzing reflection and transmission of ocean waves from a semi-infinlte elastic plate with a draft is developed. The relation of energy conservation for plates with three different edge conditions （ free, simply supported and built-in） is also derived. It is found that the present method satisfies the energy relation very well. The effects of draft on wave reflection and transmission coefficients as well as on the vertical vibration of the plates are examined through numerical tests. It is demonstrated that the zero draft assumption works well for low wave frequencies, but the effect of plate draft becomes significant for high wave frequencies.展开更多
Concentrating solar thermal power system can provide low carbon,renewable energy resources in countries or regions with strong solar irradiation.For this kind of power plant which is likely to be located in the arid a...Concentrating solar thermal power system can provide low carbon,renewable energy resources in countries or regions with strong solar irradiation.For this kind of power plant which is likely to be located in the arid area,natural draft dry cooling tower is a promising choice.To develop the experimental studies on small cooling tower,a 20 m high natural draft dry cooling tower with fully instrumented measurement system was established by the Queensland Geothermal Energy Centre of Excellence.The performance of this cooling tower was measured with the constant heat input of 600 kW and 840 kW and with ambient temperature ranging from 20 ℃ to 32 ℃.The cooling tower numerical model was refined and validated with the experimental data.The model of 1 MW concentrating solar thermal supercritical CO2 power cycle was developed and integrated with the cooling tower model.The influences of changing ambient temperature and the performance of the cooling tower on efficiency of the power system were simulated.The differences of the mechanism of the ambient temperature effect on Rankine cycle and supercritical CO2 Brayton cycle were analysed and discussed.展开更多
On the basis of a potential theory and Euler-Bernoulli beam theory, an analytical solution for oblique wave scattering by a semi-infinite elastic plate with finite draft floating on a step topography is developed usin...On the basis of a potential theory and Euler-Bernoulli beam theory, an analytical solution for oblique wave scattering by a semi-infinite elastic plate with finite draft floating on a step topography is developed using matched eigenfunction expansions. Different from previous studies, the effects of a wave incident angle, a plate draft, three different plate edge conditions （free, simply supported and built-in） and a sea-bottom topography are all taken into account. Moreover, the plate edge conditions are directly incorporated into linear algebraic equations for determining unknown expansion coefficients in velocity potentials, which leads to a simple and efficient solving procedure. Numerical results show that the convergence of the present solution is good, and an energy conservation relation is well satisfied. Also, the present predictions are in good agreement with known results for special cases. The effects of the wave incident angle, the plate draft, the plate edge conditions and the sea-bottom topography on various hydrodynamic quantities are analyzed. Some useful results are presented for engineering designs.展开更多
This article reports the findings on the adverse effect of the crosswind on the performance of natural draft cooling towers through numerical computation with the k-epsilon eddy-viscosity turbulence model. It is obser...This article reports the findings on the adverse effect of the crosswind on the performance of natural draft cooling towers through numerical computation with the k-epsilon eddy-viscosity turbulence model. It is observed here that the cause of the adverse effect of the crosswind on the cooling towers call be attributed to the around flow effect which destroys the radial inflow into the cooling towers when the wind is absent. Hence, a significant deterioration in the heat transfer from the heat exchangers at lateral sides occurs.展开更多
This paper discusses that there are two sorts of group consensus in Hall for Workshop of Meta-synthetic Engineering： draft consensus and decisive consensus, which are respectively formed in the two synchronous stages...This paper discusses that there are two sorts of group consensus in Hall for Workshop of Meta-synthetic Engineering： draft consensus and decisive consensus, which are respectively formed in the two synchronous stages in the process of ＂synchronous stages 1- asynchronous stages- synchronous stages 2＂, and focuses on the concept of draft consensus. Then proposes a draft consensus building model and its solution method called Consensus Building Graph, by which claim concern value, claim support value, claim authority value and claim consensus value can be calculated real time for reaching a consensus, and designs a computer aided consensus building system called Internet based Group Discussion Environment. The model follows the methodology of meta-synthesis from qualitative to quantitative analysis in which computers and humans are combined to solve complex problems.展开更多
文摘The Arctic region is experiencing accelerated sea ice melt and increased iceberg detachment from glaciers due to climate change.These drifting icebergs present a risk and engineering challenge for subsea installations traversing shallow waters,where ice-berg keels may reach the seabed,potentially damaging subsea structures.Consequently,costly and time-intensive iceberg manage-ment operations,such as towing and rerouting,are undertaken to safeguard subsea and offshore infrastructure.This study,therefore,explores the application of extra tree regression(ETR)as a robust solution for estimating iceberg draft,particularly in the preliminary phases of decision-making for iceberg management projects.Nine ETR models were developed using parameters influencing iceberg draft.Subsequent analyses identified the most effective models and significant input variables.Uncertainty analysis revealed that the superior ETR model tended to overestimate iceberg drafts;however,it achieved the highest precision,correlation,and simplicity in estimation.Comparison with decision tree regression,random forest regression,and empirical methods confirmed the superior perfor-mance of ETR in predicting iceberg drafts.
基金Project (50935007) supported by the National Natural Science Foundation for Key Program of ChinaProject (2010CB731701) supported by the National Basic Research Program of ChinaProject (50905145) supported by the National Natural Science Foundation of China
文摘In order to study influences of geometric parameters on the T-shaped components local loading process, a new mathematical model considering the fillet radius and draft angle was established by using the slab method. The results obtained by the mathematical model agree with the data form experiment and numerical simulation, and the results are closer to the experimental and simulation results. The influence of draft angle may be neglected under the forming conditions used. The influence of fillet radius is notable, especially in the case that the ratio of fillet radius to rib width is less than 0.75.
基金The National Natural Science Foundation of China(No.50478113)the Leading Academic Discipline Project of Shanghai Municipal Education Commission(No.J50502)
文摘To study the draft sensation distribution of an air jet supply system in a large space building in summer,experiments are conducted in a large laboratory.The temperature,velocity and draft sensation distributions at a nozzle height of 4 m in the occupied zone are obtained.Then,the numerical simulation under the test condition is carried out by the computational fluid dynamics（CFD）method.The calculation results of the indoor vertical temperature and the draft sensation distribution are validated by the test data.Simulations with different nozzle heights are conducted.The satisfactory air supply condition is determined by analyzing the draft sensations and the temperatures in the occupied zone under three conditions.The simulation results show that the optimal draft sensation distribution and the uniform temperature and velocity fields can be obtained at a nozzle height of 5 m.
文摘This study set out to investigate the effect of operational parameters (i.e. ripping depth and operational speed) during a ripping operation on the draft requirement during ripping in a sandy-clay soil. Field experiments, laboratory tests and numerical modelling techniques were utilised to observe how the draft force varied with changing values of the operational parameters. The discrete element method in the EDEM Academic<sup>TM</sup> software platform was employed to model the soil en-masse to obtain a virtual experimentation platform on which different treatments combing different settings of the operational parameters were investigated. Statistical methods, including ANOVA, regression analysis and the student t-test were applied to establish the significance of the effect of the operational parameters on the draft requirement;statistical analysis revealed that the draft increased linearly with the ripping depth and operating speed suggesting that they are directly proportional. Lower values of the ripping depth and operating speed were found to give the minimum amount of the draft requirement.
基金National Natural Science Foundation of China(No.50775034)
文摘The mechanism of the staple yarn's drafting waves during roller drafting is analyzed in this paper.It's concluded that the dynamic friction coefficient is greater than the static friction coefficient on the friction behavior of fibers,and the difference is largely responsible for the "stick-slip" motion of fibers which causes the drafting waves during drafting.In this paper,it's expected that when a high frequency undulating wave is imposed on the fiber strand in the drafting zone of roller system,the friction among fibers is dominated by the dynamic friction rather than the static friction,and thus the "stick-slip" motion will be eliminated.As a result,the fiber binding effect causing drafting waves can be significantly reduced.This hypothesis is verified by an experiment,and it can be applied in developing new spinning drafting device.
文摘The crux of this paper is based on the pattern drafting of woven fabrics. It is necessary because many textile designers or weavers cannot generate and develop their personal pattern drafts for weaving. It is obvious that they mainly copy other people’s designs to weave. This paper therefore has provided an easy and simple way to learn, focus and develop their original designs to weave. The practical production method is used to create, generate and develop the pattern drafts in this paper. The paper focuses on the components of the pattern draft which will surely help to forecast and have a view of the appearance of the design before it is woven on the cloth. In conclusion, the weaver will be able to record and document his/her original works for posterity.
文摘Overview Heats stroke(HS)is severe sunstroke caused by a rapid increase in one’s core temperature in excess of 40°C from exposure to a hot and humid environment.HS is accompanied by serious clinical syndromes that damage multiple organ systems.h ese syndromes include burning skin and impaired awareness,such as delir ium,conv ul sions,and loss of consciousness.Exertional heat stroke(EHS)is caused by a rapid increase in one’s core temperature in excess of 40°C from high intensity
基金Supported by Ministry of Industry and Information(No.K24097)
文摘The value of form factor k at different drafts is important in predicting full-scale total resistance and speed for different types of ships. In the ITTC community, most organizations predict form factor k using a low-speed model test. However, this method is problematic for ships with bulbous bows and transom. In this article, a Computational Fluid Dynamics(CFD)-based method is introduced to obtain k for different type of ships at different drafts, and a comparison is made between the CFD method and the model test. The results show that the CFD method produces reasonable k values. A grid generating method and turbulence model are briefly discussed in the context of obtaining a consistent k using CFD.
基金The present work was financially supported by the National Natural Science Foundation of China under contract No.50428908the Program for Changjiang Scholars and Innovative Research Team in University of China under contract No.IRT0420.
文摘A method for analyzing reflection and transmission of ocean waves from a semi-infinlte elastic plate with a draft is developed. The relation of energy conservation for plates with three different edge conditions （ free, simply supported and built-in） is also derived. It is found that the present method satisfies the energy relation very well. The effects of draft on wave reflection and transmission coefficients as well as on the vertical vibration of the plates are examined through numerical tests. It is demonstrated that the zero draft assumption works well for low wave frequencies, but the effect of plate draft becomes significant for high wave frequencies.
文摘Concentrating solar thermal power system can provide low carbon,renewable energy resources in countries or regions with strong solar irradiation.For this kind of power plant which is likely to be located in the arid area,natural draft dry cooling tower is a promising choice.To develop the experimental studies on small cooling tower,a 20 m high natural draft dry cooling tower with fully instrumented measurement system was established by the Queensland Geothermal Energy Centre of Excellence.The performance of this cooling tower was measured with the constant heat input of 600 kW and 840 kW and with ambient temperature ranging from 20 ℃ to 32 ℃.The cooling tower numerical model was refined and validated with the experimental data.The model of 1 MW concentrating solar thermal supercritical CO2 power cycle was developed and integrated with the cooling tower model.The influences of changing ambient temperature and the performance of the cooling tower on efficiency of the power system were simulated.The differences of the mechanism of the ambient temperature effect on Rankine cycle and supercritical CO2 Brayton cycle were analysed and discussed.
基金The National Natural Science Foundation of China under contract Nos 51490675,51322903 and 51279224
文摘On the basis of a potential theory and Euler-Bernoulli beam theory, an analytical solution for oblique wave scattering by a semi-infinite elastic plate with finite draft floating on a step topography is developed using matched eigenfunction expansions. Different from previous studies, the effects of a wave incident angle, a plate draft, three different plate edge conditions （free, simply supported and built-in） and a sea-bottom topography are all taken into account. Moreover, the plate edge conditions are directly incorporated into linear algebraic equations for determining unknown expansion coefficients in velocity potentials, which leads to a simple and efficient solving procedure. Numerical results show that the convergence of the present solution is good, and an energy conservation relation is well satisfied. Also, the present predictions are in good agreement with known results for special cases. The effects of the wave incident angle, the plate draft, the plate edge conditions and the sea-bottom topography on various hydrodynamic quantities are analyzed. Some useful results are presented for engineering designs.
基金The project supported by the National Natural Science Foundation of China (19725208) and the National Climbing project of China
文摘This article reports the findings on the adverse effect of the crosswind on the performance of natural draft cooling towers through numerical computation with the k-epsilon eddy-viscosity turbulence model. It is observed here that the cause of the adverse effect of the crosswind on the cooling towers call be attributed to the around flow effect which destroys the radial inflow into the cooling towers when the wind is absent. Hence, a significant deterioration in the heat transfer from the heat exchangers at lateral sides occurs.
基金Supported by the National Natural Science Foundation ofChina (69775022)the Natural Science Foundation of Hubei Province(2007ABA025)
文摘This paper discusses that there are two sorts of group consensus in Hall for Workshop of Meta-synthetic Engineering： draft consensus and decisive consensus, which are respectively formed in the two synchronous stages in the process of ＂synchronous stages 1- asynchronous stages- synchronous stages 2＂, and focuses on the concept of draft consensus. Then proposes a draft consensus building model and its solution method called Consensus Building Graph, by which claim concern value, claim support value, claim authority value and claim consensus value can be calculated real time for reaching a consensus, and designs a computer aided consensus building system called Internet based Group Discussion Environment. The model follows the methodology of meta-synthesis from qualitative to quantitative analysis in which computers and humans are combined to solve complex problems.
