Nowadays some new ideas of fractional derivatives have been used successfully in the present research community to study different types of mathematical models.Amongst them,the significant models of fluids and heat or...Nowadays some new ideas of fractional derivatives have been used successfully in the present research community to study different types of mathematical models.Amongst them,the significant models of fluids and heat or mass transfer are on priority.Most recently a new idea of fractal-fractional derivative is introduced;however,it is not used for heat transfer in channel flow.In this article,we have studied this new idea of fractal fractional operators with power-law kernel for heat transfer in a fluid flow problem.More exactly,we have considered the free convection heat transfer for a Newtonian fluid.The flow is bounded between two parallel static plates.One of the plates is heated constantly.The proposed problem is modeled with a fractal fractional derivative operator with a power-law kernel and solved via the Laplace transform method to find out the exact solution.The results are graphically analyzed via MathCad-15 software to study the behavior of fractal parameters and fractional parameter.For the influence of temperature and velocity profile,it is observed that the fractional parameter raised the velocity and temperature as compared to the fractal operator.Therefore,a combined approach of fractal fractional explains the memory of the function better than fractional only.展开更多
Straw checkerboard sand barriers with a porous structure that consists of a pervious upper portion and a dense lower portion are widely used to achieve great sand control effect.Considering this,and resolving the seri...Straw checkerboard sand barriers with a porous structure that consists of a pervious upper portion and a dense lower portion are widely used to achieve great sand control effect.Considering this,and resolving the serious earth surface undercutting problem after HDPE sandbreak net checkboard barriers setting,the authors used HDPE(high-density polyethylene)materials to prepare new sandbreak materials with a similar porous structure.Through wind tunnel simulations and field sand control monitoring,we compared the sand control effect of three HDPE sandbreak nets with different porosity structure.Compared to the sandbreak net with uniform porosity structure,the three types of HDPE sandbreak nets with different porosity structure had poorer effect on reducing sand transport rates,but had longer effective protection distance before sandbreak nets at low wind velocity conditions(<12 m/s),longer effective protection distance at high wind velocity(>14 m/s)and longer effective protection distance between sandbreak nets at all experimental wind velocity conditions.Wind and sand control effect characteristics of HDPE sandbreak nets with different porosity structure provide an ideal material on semiburied checkerboard sand barriers for sand stabilization.By contrast,uniform-type sandbreak nets are used as materials on high upright sand fences for sand blocking.These HDPE sandbreak nets can be used to replace traditional sandbreak materials and have a very high potential for widespread and popular application in aeolian sand disaster control.展开更多
-The construction of breakwaters in China in more than 40 years since the founding of the People’s Republic of China is reviewed. The construction of two main types of breakwater, upright breakwaters and rubble mound...-The construction of breakwaters in China in more than 40 years since the founding of the People’s Republic of China is reviewed. The construction of two main types of breakwater, upright breakwaters and rubble mound breakwaters, and the way in which they are built are expounded. Recommendations to improve the technology for future breakwater construction are presented.展开更多
Objective:To examine the effect of upright and ambulant positions versus lying down during the active first stage of labor on birth outcomes for nulliparous women.Methods:This is a randomized controlled clinical trial...Objective:To examine the effect of upright and ambulant positions versus lying down during the active first stage of labor on birth outcomes for nulliparous women.Methods:This is a randomized controlled clinical trial conducted at the delivery department of Damanhour Educational Institute,El Behira Governorate,Egypt.The study sample involved 150 parturient women equally divided into intervention and control groups using randomization block technique.The researchers used four tools for data collection:Demographic data interview schedule,World Health Organization Partograph,Apgar’s score,to evaluate neonatal outcomes,and visual analogue pain intensity scale.For the study group,the parturient women were encouraged to assume one of the upright positions or ambulating around the bed so as to maintain the pelvis in vertical plane as far as possible for 20-25 min for every 1 h.The control group received routine hospital care,which includes lying down in bed.IBM SPSS 23.0 was used to analyze the data.Results:Significant differences(P<0.05)were observed between the study and control groups in relation to cervical dilation,fetal head descent,uterine contractions interval,and frequency.The duration of the first stage of labor significantly reduced(P=0.018)in the intervention group compared with control group.No significant differences(P>0.05)were observed between both groups in term of emergency cesarean birth rates,oxytocin use,and neonatal outcomes.Conclusions:This study proves that upright and ambulant positions significantly enhance uterine contractility,cervical dilatation,and fetal head descent and reduce the first stage duration.展开更多
基金This work was supported by the Natural Science Foundation of China(Grant Nos.61673169,11701176,11626101,11601485).
文摘Nowadays some new ideas of fractional derivatives have been used successfully in the present research community to study different types of mathematical models.Amongst them,the significant models of fluids and heat or mass transfer are on priority.Most recently a new idea of fractal-fractional derivative is introduced;however,it is not used for heat transfer in channel flow.In this article,we have studied this new idea of fractal fractional operators with power-law kernel for heat transfer in a fluid flow problem.More exactly,we have considered the free convection heat transfer for a Newtonian fluid.The flow is bounded between two parallel static plates.One of the plates is heated constantly.The proposed problem is modeled with a fractal fractional derivative operator with a power-law kernel and solved via the Laplace transform method to find out the exact solution.The results are graphically analyzed via MathCad-15 software to study the behavior of fractal parameters and fractional parameter.For the influence of temperature and velocity profile,it is observed that the fractional parameter raised the velocity and temperature as compared to the fractal operator.Therefore,a combined approach of fractal fractional explains the memory of the function better than fractional only.
基金fund by Strategic Priority Research Program of the Chinese Academy of Sciences(XD23060201)the National Natural Science Foundation of China(41730644,42171016,)。
文摘Straw checkerboard sand barriers with a porous structure that consists of a pervious upper portion and a dense lower portion are widely used to achieve great sand control effect.Considering this,and resolving the serious earth surface undercutting problem after HDPE sandbreak net checkboard barriers setting,the authors used HDPE(high-density polyethylene)materials to prepare new sandbreak materials with a similar porous structure.Through wind tunnel simulations and field sand control monitoring,we compared the sand control effect of three HDPE sandbreak nets with different porosity structure.Compared to the sandbreak net with uniform porosity structure,the three types of HDPE sandbreak nets with different porosity structure had poorer effect on reducing sand transport rates,but had longer effective protection distance before sandbreak nets at low wind velocity conditions(<12 m/s),longer effective protection distance at high wind velocity(>14 m/s)and longer effective protection distance between sandbreak nets at all experimental wind velocity conditions.Wind and sand control effect characteristics of HDPE sandbreak nets with different porosity structure provide an ideal material on semiburied checkerboard sand barriers for sand stabilization.By contrast,uniform-type sandbreak nets are used as materials on high upright sand fences for sand blocking.These HDPE sandbreak nets can be used to replace traditional sandbreak materials and have a very high potential for widespread and popular application in aeolian sand disaster control.
文摘-The construction of breakwaters in China in more than 40 years since the founding of the People’s Republic of China is reviewed. The construction of two main types of breakwater, upright breakwaters and rubble mound breakwaters, and the way in which they are built are expounded. Recommendations to improve the technology for future breakwater construction are presented.
文摘Objective:To examine the effect of upright and ambulant positions versus lying down during the active first stage of labor on birth outcomes for nulliparous women.Methods:This is a randomized controlled clinical trial conducted at the delivery department of Damanhour Educational Institute,El Behira Governorate,Egypt.The study sample involved 150 parturient women equally divided into intervention and control groups using randomization block technique.The researchers used four tools for data collection:Demographic data interview schedule,World Health Organization Partograph,Apgar’s score,to evaluate neonatal outcomes,and visual analogue pain intensity scale.For the study group,the parturient women were encouraged to assume one of the upright positions or ambulating around the bed so as to maintain the pelvis in vertical plane as far as possible for 20-25 min for every 1 h.The control group received routine hospital care,which includes lying down in bed.IBM SPSS 23.0 was used to analyze the data.Results:Significant differences(P<0.05)were observed between the study and control groups in relation to cervical dilation,fetal head descent,uterine contractions interval,and frequency.The duration of the first stage of labor significantly reduced(P=0.018)in the intervention group compared with control group.No significant differences(P>0.05)were observed between both groups in term of emergency cesarean birth rates,oxytocin use,and neonatal outcomes.Conclusions:This study proves that upright and ambulant positions significantly enhance uterine contractility,cervical dilatation,and fetal head descent and reduce the first stage duration.
