Increasing the aerodynamic load on compressor blades helps to obtain a higher pressure ratio in lower rotational speeds. Considering the high aerodynamic load effects and structural concerns in the design process, it ...Increasing the aerodynamic load on compressor blades helps to obtain a higher pressure ratio in lower rotational speeds. Considering the high aerodynamic load effects and structural concerns in the design process, it is possible to obtain higher pressure ratios compared to conventional compressors. However, it must be noted that imposing higher aerodynamic loads results in higher loss coemcients and deteriorates the overall performance. To avoid the loss increase, the boundary layer quality must be studied carefully over the blade suction surface. Employment of advanced shaped airfoils （like CDAs）, slotted blades or other boundary layer control methods has helped the de- signers to use higher aerodynamic loads on compressor blades. Tandem cascade is a passive boundary layer control method, which is based on using the flow momentum to control the boundary layer on the suction surface and also to avoid the probable separation caused by higher aerodynamic loads. In fact, the front pressure side flow momentum helps to compensate the positive pressure gradient over the aft blade＇s suction side. Also, in compari- son to the single blade stators, tandem variable stators have more degrees of freedom, and this issue increases the possibility of finding enhanced conditions in the compressor off-design performance. In the current study, a 3D design procedure for an axial flow tandem compressor stage has been applied to design a highly loaded stage. Following, this design is numerically investigated using a CFD code and the stage characteristic map is reported. Also, the effect of various stator stagger angles on the compressor performance and especially on the compressor surge margin has been discussed. To validate the CFD method, another known compressor stage is presented and its performance is numerically investigated and the results are compared with available experimental results.展开更多
Today,with nonstop improvement in computational power,Large-Eddy Simulation(LES) is a high demanding research tool for predicting engineering flows.Such flows on high pressure condition like diesel engines is extensiv...Today,with nonstop improvement in computational power,Large-Eddy Simulation(LES) is a high demanding research tool for predicting engineering flows.Such flows on high pressure condition like diesel engines is extensively employed in ground and marine transportation,oblige the designer to control and predict toxic pollutants,while maintaining or improving their high thermal efficiency.This becomes one of the main challenging issues in decades.In the present work,numerical investigation of diffusion flame dynamics is performed in the near-field of high-Reynolds jet flow on high pressure condition encountered in diesel engine applications.This work discusses the implementation of Partially Stirred Reactor(PaSR) combustion model by the approaches of large eddy simulation(LES).The simulation results show that LES,in comparison with Reynolds-Averaged Navier-Stokes(RANS) simulation predicts and captures transient phenomena very well.These phenomena such as unsteadiness and curvature are inherent in the near-field of high Reynolds diffusion flame.The outcomes of this research are compared and validated by other researchers' results.Detailed comparisons of the statistics show good agreement with the corresponding experiments.展开更多
Let R be a commutative Noetherian ring and p be a prime ideal of R such that the ideal pRp is principal and ht(p)≠0. In this note, the anthors describe the explicit structure of the injective envelope of the R-module...Let R be a commutative Noetherian ring and p be a prime ideal of R such that the ideal pRp is principal and ht(p)≠0. In this note, the anthors describe the explicit structure of the injective envelope of the R-module R/p.展开更多
Many studies have so far confirmed the efficiency of phytochemicals in the treatment of prostate cancer.Eupatorin,a flavonoid with a wide range of phytomedical activities,suppresses proliferation of and induces apopto...Many studies have so far confirmed the efficiency of phytochemicals in the treatment of prostate cancer.Eupatorin,a flavonoid with a wide range of phytomedical activities,suppresses proliferation of and induces apoptosis of multiple cancer cell lines.However,low solubility,poor bioavailability,and rapid degradation limit its efficacy.The aim of our study was to evaluate whether the use of mPEG-b-poly(lactic-co-glycolic)acid(PLGA)coated iron oxide nanoparticles as a carrier could enhance the therapeutic efficacy of eupatorin in DU-145 and LNcaP human prostate cancer cell lines.Nanoparticles were prepared by the co-precipitation method and were fully characterized for morphology,surface charge,particle size,drug loading,encapsulation efficiency and in vitro drug-release profile.The inhibitory effect of nanoparticles on cell viability was evaluated by MTT test.Apoptosis was then determined by Hoechest staining,cell cycle analysis,NO production,annexin/propidium iodide(PI)assay,and Western blotting.The results indicated that eupatorin was successfully entrapped in Fe_(3)O_(4)@mPEG-b-PLGA nanoparticles with an efficacy of(90.99±2.1)%.The nanoparticle’s size was around(58.5±4)nm with a negative surface charge[(-34.16±1.3)mV].In vitro release investigation showed a 30% initial burst release of eupatorin in 24 h,followed by sustained release over 200 h.The MTT assay indicated that eupatorinloaded Fe_(3)O_(4)@mPEG-b-PLGA nanoparticles exhibited a significant decrease in the growth rate of DU-145 and LNcaP cells and their IC50 concentrations were 100 μM and 75 μM,respectively.Next,apoptosis was confirmed by nuclear condensation,enhancement of cell population in the sub-G1 phase and increased NO level.Annexin/PI analysis demonstrated that eupatorin-loaded Fe_(3)O_(4)@mPEG-b-PLGA nanoparticles could increase apoptosis and decrease necrosis frequency.Finally,Western blotting analysis confirmed these results and showed that Bax/Bcl-2 ratio and the cleaved caspase-3 level were up-regulated by the designing nanoparticles.展开更多
A classical question of Yoneda asks when the tensor product of two injective modules is injective. A complete answer to this question was given by Enochs and Jenda in 1991. In this paper the analogue question for pure...A classical question of Yoneda asks when the tensor product of two injective modules is injective. A complete answer to this question was given by Enochs and Jenda in 1991. In this paper the analogue question for pure-injective modules is studied.展开更多
文摘Increasing the aerodynamic load on compressor blades helps to obtain a higher pressure ratio in lower rotational speeds. Considering the high aerodynamic load effects and structural concerns in the design process, it is possible to obtain higher pressure ratios compared to conventional compressors. However, it must be noted that imposing higher aerodynamic loads results in higher loss coemcients and deteriorates the overall performance. To avoid the loss increase, the boundary layer quality must be studied carefully over the blade suction surface. Employment of advanced shaped airfoils （like CDAs）, slotted blades or other boundary layer control methods has helped the de- signers to use higher aerodynamic loads on compressor blades. Tandem cascade is a passive boundary layer control method, which is based on using the flow momentum to control the boundary layer on the suction surface and also to avoid the probable separation caused by higher aerodynamic loads. In fact, the front pressure side flow momentum helps to compensate the positive pressure gradient over the aft blade＇s suction side. Also, in compari- son to the single blade stators, tandem variable stators have more degrees of freedom, and this issue increases the possibility of finding enhanced conditions in the compressor off-design performance. In the current study, a 3D design procedure for an axial flow tandem compressor stage has been applied to design a highly loaded stage. Following, this design is numerically investigated using a CFD code and the stage characteristic map is reported. Also, the effect of various stator stagger angles on the compressor performance and especially on the compressor surge margin has been discussed. To validate the CFD method, another known compressor stage is presented and its performance is numerically investigated and the results are compared with available experimental results.
文摘Today,with nonstop improvement in computational power,Large-Eddy Simulation(LES) is a high demanding research tool for predicting engineering flows.Such flows on high pressure condition like diesel engines is extensively employed in ground and marine transportation,oblige the designer to control and predict toxic pollutants,while maintaining or improving their high thermal efficiency.This becomes one of the main challenging issues in decades.In the present work,numerical investigation of diffusion flame dynamics is performed in the near-field of high-Reynolds jet flow on high pressure condition encountered in diesel engine applications.This work discusses the implementation of Partially Stirred Reactor(PaSR) combustion model by the approaches of large eddy simulation(LES).The simulation results show that LES,in comparison with Reynolds-Averaged Navier-Stokes(RANS) simulation predicts and captures transient phenomena very well.These phenomena such as unsteadiness and curvature are inherent in the near-field of high Reynolds diffusion flame.The outcomes of this research are compared and validated by other researchers' results.Detailed comparisons of the statistics show good agreement with the corresponding experiments.
基金This research is in part supported by a grant from IPM.
文摘Let R be a commutative Noetherian ring and p be a prime ideal of R such that the ideal pRp is principal and ht(p)≠0. In this note, the anthors describe the explicit structure of the injective envelope of the R-module R/p.
文摘Many studies have so far confirmed the efficiency of phytochemicals in the treatment of prostate cancer.Eupatorin,a flavonoid with a wide range of phytomedical activities,suppresses proliferation of and induces apoptosis of multiple cancer cell lines.However,low solubility,poor bioavailability,and rapid degradation limit its efficacy.The aim of our study was to evaluate whether the use of mPEG-b-poly(lactic-co-glycolic)acid(PLGA)coated iron oxide nanoparticles as a carrier could enhance the therapeutic efficacy of eupatorin in DU-145 and LNcaP human prostate cancer cell lines.Nanoparticles were prepared by the co-precipitation method and were fully characterized for morphology,surface charge,particle size,drug loading,encapsulation efficiency and in vitro drug-release profile.The inhibitory effect of nanoparticles on cell viability was evaluated by MTT test.Apoptosis was then determined by Hoechest staining,cell cycle analysis,NO production,annexin/propidium iodide(PI)assay,and Western blotting.The results indicated that eupatorin was successfully entrapped in Fe_(3)O_(4)@mPEG-b-PLGA nanoparticles with an efficacy of(90.99±2.1)%.The nanoparticle’s size was around(58.5±4)nm with a negative surface charge[(-34.16±1.3)mV].In vitro release investigation showed a 30% initial burst release of eupatorin in 24 h,followed by sustained release over 200 h.The MTT assay indicated that eupatorinloaded Fe_(3)O_(4)@mPEG-b-PLGA nanoparticles exhibited a significant decrease in the growth rate of DU-145 and LNcaP cells and their IC50 concentrations were 100 μM and 75 μM,respectively.Next,apoptosis was confirmed by nuclear condensation,enhancement of cell population in the sub-G1 phase and increased NO level.Annexin/PI analysis demonstrated that eupatorin-loaded Fe_(3)O_(4)@mPEG-b-PLGA nanoparticles could increase apoptosis and decrease necrosis frequency.Finally,Western blotting analysis confirmed these results and showed that Bax/Bcl-2 ratio and the cleaved caspase-3 level were up-regulated by the designing nanoparticles.
文摘A classical question of Yoneda asks when the tensor product of two injective modules is injective. A complete answer to this question was given by Enochs and Jenda in 1991. In this paper the analogue question for pure-injective modules is studied.
