The objective of the presented study is to perform a vibration analysis and investigate the stability of a viscoelastic-fluid conveying pipe with an intermediate support.The mathematical model is elaborated in the fra...The objective of the presented study is to perform a vibration analysis and investigate the stability of a viscoelastic-fluid conveying pipe with an intermediate support.The mathematical model is elaborated in the framework of the Euler-Bernoulli beam theory in combination with the Kelvin-Voight viscoelastic approach.The resulting differential equation of motion and the related boundary conditions and compatibility conditions in the mid-span support are solved analytically using a power series method.The results show that an intermediate support located atξ_(s)=0.1 andξ_(s)=0.5 increases the critical velocity up to 35%and 50.15%,respectively.Also,the non-dimensional critical velocity for an intermediate support atξ_(s)=0.1 is 4.83.展开更多
Further development in the field of geothermal energy require reliable reference data on the thermophysical properties of geothermal waters,namely,on the thermal conductivity and viscosity of aqueous salt solutions at...Further development in the field of geothermal energy require reliable reference data on the thermophysical properties of geothermal waters,namely,on the thermal conductivity and viscosity of aqueous salt solutions at temperatures of 293–473 K,pressures Ps=100 MPa,and concentrations of 0–25 wt.%.Given the lack of data and models,especially for the dynamic viscosity of aqueous salt solutions at a pressure of above 40 MPa,generalized formulas are presented here,by which these gaps can be filled.The article presents a generalized formula for obtaining reliable data on the thermal conductivity of water aqueous solutions of salts for Ps=100 MPa,temperatures of 293–473 K and concentrations of 0%–25%(wt.%),as well as generalized formulas for the dynamic viscosity of water up to pressures of 500 MPa and aqueous solutions of salts for Ps=100 MPa,temperatures 333–473 K,and concentration 0%–25%.The obtained values agree with the experimental data within 1.6%.展开更多
The utilization of vortex generators to increase heat transfer from cylinders installed inside a duct is investigated.In particular,a channel containing eight cylinders with volumetric heat sources is considered for d...The utilization of vortex generators to increase heat transfer from cylinders installed inside a duct is investigated.In particular,a channel containing eight cylinders with volumetric heat sources is considered for different values of the Reynolds number.The effective possibility to use vortex generators with different sizes to increase heat transfer and,consequently,reduce the surface temperature of the cylinders is examined.Also,the amount of pressure drop inside the channel due to the presence of vortex generators is considered and compared with the cases without vortex generators.The results show that although the addition of generators increases the pressure drop,it strongly contributes to increase the heat transfer coefficient inside the duct(up to 80–90%).展开更多
A systematic study of two-phase(water-air)currents in open channels(water-air)has been conducted by means of experiments and numerical simulations.A dedicated device has been designed and manufactured on purpose.The n...A systematic study of two-phase(water-air)currents in open channels(water-air)has been conducted by means of experiments and numerical simulations.A dedicated device has been designed and manufactured on purpose.The numerical simulations have been based on the solution of a system of mass,momentum and energy balance equations for a two-phase fluid.The effect of different influential parameters has been explored,namely,velocity and dimensions of the channel,surface pressure and tension.展开更多
Loading rHuEPO-alpha drug on the surface of magnesium oxide nanoparticles further improves the effect of the drug as a treatment for anemia.After preparation of magnesium oxide nanoparticles by precipitation method,it...Loading rHuEPO-alpha drug on the surface of magnesium oxide nanoparticles further improves the effect of the drug as a treatment for anemia.After preparation of magnesium oxide nanoparticles by precipitation method,it was diagnosed by X-ray diffraction and Transmission Electron Microscopy.the loaded was diagnosed by Docking program,UV-Visible and Transmission Electron Microscopy.The study of LD50 was for thirty male mice.Magnesium Oxide nanoparticles had an average crystallite size of 8.42 nm.oral LD50 test was 896 mg/kg.Docking results presented a high energy binding with force linkage due to the link of the oxygen atom of MgO NPs with three hydrogen bonds of amino acids in the rHuEPO-alpha structure.The UV-Visible result was certain that all rHuEPO-alpha drug was loaded on the surface of MgO NPs.TEM shows that the average particle size was 9.94 nm after loaded of the rHuEPO-alpha drug on MgO NPs while was 9 nm before the loaded.Magnesium oxide nanoparticles may exhibit an effect on increasing the efficacy of rHuEPO-alpha after the loaded,leading to elevated hemoglobin and reduced anemia disease.展开更多
文摘The objective of the presented study is to perform a vibration analysis and investigate the stability of a viscoelastic-fluid conveying pipe with an intermediate support.The mathematical model is elaborated in the framework of the Euler-Bernoulli beam theory in combination with the Kelvin-Voight viscoelastic approach.The resulting differential equation of motion and the related boundary conditions and compatibility conditions in the mid-span support are solved analytically using a power series method.The results show that an intermediate support located atξ_(s)=0.1 andξ_(s)=0.5 increases the critical velocity up to 35%and 50.15%,respectively.Also,the non-dimensional critical velocity for an intermediate support atξ_(s)=0.1 is 4.83.
文摘Further development in the field of geothermal energy require reliable reference data on the thermophysical properties of geothermal waters,namely,on the thermal conductivity and viscosity of aqueous salt solutions at temperatures of 293–473 K,pressures Ps=100 MPa,and concentrations of 0–25 wt.%.Given the lack of data and models,especially for the dynamic viscosity of aqueous salt solutions at a pressure of above 40 MPa,generalized formulas are presented here,by which these gaps can be filled.The article presents a generalized formula for obtaining reliable data on the thermal conductivity of water aqueous solutions of salts for Ps=100 MPa,temperatures of 293–473 K and concentrations of 0%–25%(wt.%),as well as generalized formulas for the dynamic viscosity of water up to pressures of 500 MPa and aqueous solutions of salts for Ps=100 MPa,temperatures 333–473 K,and concentration 0%–25%.The obtained values agree with the experimental data within 1.6%.
文摘The utilization of vortex generators to increase heat transfer from cylinders installed inside a duct is investigated.In particular,a channel containing eight cylinders with volumetric heat sources is considered for different values of the Reynolds number.The effective possibility to use vortex generators with different sizes to increase heat transfer and,consequently,reduce the surface temperature of the cylinders is examined.Also,the amount of pressure drop inside the channel due to the presence of vortex generators is considered and compared with the cases without vortex generators.The results show that although the addition of generators increases the pressure drop,it strongly contributes to increase the heat transfer coefficient inside the duct(up to 80–90%).
基金The article was prepared as part of the state task“Research and development of complex energy-saving and thermoelectric regenerative systems”Application No.2019–1497,Subject No.FZWG-2020-0034。
文摘A systematic study of two-phase(water-air)currents in open channels(water-air)has been conducted by means of experiments and numerical simulations.A dedicated device has been designed and manufactured on purpose.The numerical simulations have been based on the solution of a system of mass,momentum and energy balance equations for a two-phase fluid.The effect of different influential parameters has been explored,namely,velocity and dimensions of the channel,surface pressure and tension.
文摘Loading rHuEPO-alpha drug on the surface of magnesium oxide nanoparticles further improves the effect of the drug as a treatment for anemia.After preparation of magnesium oxide nanoparticles by precipitation method,it was diagnosed by X-ray diffraction and Transmission Electron Microscopy.the loaded was diagnosed by Docking program,UV-Visible and Transmission Electron Microscopy.The study of LD50 was for thirty male mice.Magnesium Oxide nanoparticles had an average crystallite size of 8.42 nm.oral LD50 test was 896 mg/kg.Docking results presented a high energy binding with force linkage due to the link of the oxygen atom of MgO NPs with three hydrogen bonds of amino acids in the rHuEPO-alpha structure.The UV-Visible result was certain that all rHuEPO-alpha drug was loaded on the surface of MgO NPs.TEM shows that the average particle size was 9.94 nm after loaded of the rHuEPO-alpha drug on MgO NPs while was 9 nm before the loaded.Magnesium oxide nanoparticles may exhibit an effect on increasing the efficacy of rHuEPO-alpha after the loaded,leading to elevated hemoglobin and reduced anemia disease.
