We investigated ^(50,52-54)Cr-induced fusion reactions for the synthesis of the superheavy element in the 104≤Z≤122 range.The cross sections produced in this investigation using ^(54)Cr projectiles were compared wit...We investigated ^(50,52-54)Cr-induced fusion reactions for the synthesis of the superheavy element in the 104≤Z≤122 range.The cross sections produced in this investigation using ^(54)Cr projectiles were compared with those obtained in prior experiments.The estimated cross sections from this analysis are consistent with the findings of prior studies.From the current study,the predicted cross section was found to be 42fb at 236 MeV for ^(53)Cr+^(243)Am,23.2 fb at 236 MeV for ^(54)Cr+^(247)Cm,95.6 fb at 240 MeV for ^(53)Cr+248Bk,and 1.33 fb at 242 MeV for ^(53)Cr+250Cf.Consequently,these projected cross sections with excitation energy and beam energy will be useful in future Cr-induced fusion reaction investigations.展开更多
In the present work the dynamic characteristics of Multilayer Polyurethane foam glass/fiber composite sandwich panels have been determined through Experimental Investigations. Using a Multilayer Polyurethane foam sand...In the present work the dynamic characteristics of Multilayer Polyurethane foam glass/fiber composite sandwich panels have been determined through Experimental Investigations. Using a Multilayer Polyurethane foam sandwich panel with rectangular cross-section, the natural frequencies, mode shapes and the damping ratio of sandwich panels were evaluated. Three types of boundary conditions were simulated namely, C-F-F-F (Clamped Free-Free-Free), C-F-C-F (Clam-ped-Free-Clamped-Free), C-C-C-C-(Clamped-Clamped-Clamped-Clamped). Experimental modal tests were conducted on sandwich panels with available polyurethane foam of densities 56 kg/m3, 82 kg/m3and 289 kg/m3.The traditional “strike method” has been used to measure vibration properties. The modal characteristics of the specimens have been obtained by studying their impulse response. Each specimen has been subjected to impulses through a hard tipped hammer which is provided with a force transducer and the response has been measured through the accelerometer. The impulse and the response are processed through a computer aided FFT Analyzing test system in order to extract the modal parameters. Finite Element modeling was carried out treating the facing and core as orthotropic with different elastic constants as recommended in the literature. The experimental results were validated with FEA and were found to be in good agreement.The results obtained through modal test on multilayer sandwich panels are presented. They indicate a significant variation in the dynamic parameters in case of multilayer sandwich panels for the same core density as compared to a monolayer sandwich panel.展开更多
To demonstrate the influence of sliding friction of motion on a curve, a circular path is considered for simplicity on which a person slides from the highest point to the lowest point. A slide which represents a quadr...To demonstrate the influence of sliding friction of motion on a curve, a circular path is considered for simplicity on which a person slides from the highest point to the lowest point. A slide which represents a quadrant of radius 5 m and a person of mass 60 kg are considered for comparison in this paper. A Differential equation for motion considering the fact that the normal force depends both on the sin component of weight and also on the tangential velocity, is established and is solved using integrating factor method, and the motion is analysed for different surface roughness of the slide and is compared using superimposed graphs, also the limiting value of friction coefficient at which the person just exits the slide is determined. The correction factor for exit velocity with friction as compared with the exit velocity for zero friction is determined. The fraction of energy lost to friction at the exit is evaluated. The Variation of normal force with the position of the person on the slide is plotted for different surface roughness of the slide, and the position on the slide where the normal force or the force experienced by the person is maximum, is determined and hence its maximum value is evaluated for different surface roughness. For simplicity, a point contact between the body and the slide is considered.展开更多
The aim of the research work was to numerically investigate the residual stresses induced between the layers of fiber metal laminate (FML) cylinder (glass/epoxy reinforced aluminum laminates) under buckling hydrostati...The aim of the research work was to numerically investigate the residual stresses induced between the layers of fiber metal laminate (FML) cylinder (glass/epoxy reinforced aluminum laminates) under buckling hydrostatic loading. For the analysis of buckling behavior of FML cylinders, various fiber orientations such as 0/90°, 60/30°, ±45° and ±55° and different FRP thickness of 1, 2, and 3 mm were considered. The aluminum cylinder of inner diameter 80 mm, length 800 mm and wall thickness 1 mm was modeled with SHELL281 element type and a total of 1033 elements were used for computing the induced residual stresses between the layers. The results show that magnitude of residual stresses between the layers decreased along the thickness from outer layer towards the inner layer in sine wave form. The maximum residual Von-Mises stress was at inner aluminum layer while the maximum residual radial stress was at the outermost layer of FML cylinder due to the inward pressure. Among all types of FML cylinder 0/90° fiber oriented FML cylinder exhibited the least radial stress and a maximum Von-Mises stress along the FRP thickness.展开更多
Among different sources of alternate energy,wind and solar are two prominent and promising alternatives to meet the future electricity needs for mankind.Generally,these sources are integrated at the distribution utili...Among different sources of alternate energy,wind and solar are two prominent and promising alternatives to meet the future electricity needs for mankind.Generally,these sources are integrated at the distribution utilities to supply the local distribution customers.If the power generated by these sources is bulk,then they are either integrated at the distribution/transmission level or may be operated in an island mode if feasible.The integration of these renewables in the power network will change the fault level and network topologies.These fault levels are intermittent in nature and existing protection schemes may fail to operate because of their pre-set condition.Therefore,the design and selection of a proper protection scheme is very much essential for reliable control and operation of renewable integrated power systems.Depending upon the level of infeed and location of the renewable integration,the protection requirements are different.For low renewable infeed at the distribution level,the existing relay settings are immune from any small change in the network fault current from new incoming renewables.However,bulk renewable infeed requires modification in the existing protection schemes to accommodate the fault current variation from the incoming renewables.For bulk penetration of the renewable,the requirement of modified/additional protection schemes is unavoidable.Adaptive relaying and non-adaptive relaying schemes are discussed in the literature for protection of power networks,which are experiencing dynamic fault currents and frequent changing network topologies.This article presents a detailed review of protection schemes for renewable integrated power networks which includes distribution,transmission and microgrid systems.The merits and demerits of these protection schemes are also identified in this article for the added interest of the readers.The visible scope of advance protection schemes which may be suitable for providing reliable protection for dynamic fault current networks is also explored.展开更多
The Sodium Montmorillonite(Na-MMT)is not susceptible to polymer due to its organophilic character and low basal spacing.The primary objective of this study was to improve Na-MMT platelets separation by organically mod...The Sodium Montmorillonite(Na-MMT)is not susceptible to polymer due to its organophilic character and low basal spacing.The primary objective of this study was to improve Na-MMT platelets separation by organically modifying it with cation and anion exchanges using Cetyl trimethyl ammonium bromide(CTAB)and Sodium dodecyl sulfate(SDS)respectively.Basal spacing,presence of functional groups,Zetapotential with particle size analysis and thermal stability of the Organomodified Na-MMT(OMMT)were characterized using XRD,FTIR,zeta-potential analyzer and TGA respectively.The basal spacing of CTAB modified OMMTincreased to 19.5Åfrom 11.0Åwhich corresponds to the basal spacing of Na-MMT.The SDS modified OMMT did not show any increase in the basal spacing.FTIR spectra of CTAB modified Na-MMT illustrated the attachment of CTAB functional groups to Na-MMT,while the same was absent in the case of SDS modified Na-MMT.The zeta-potential of Na-MMT shifted from–24.88 mV to 15.66 mV in the case of CTAB modified Na-MMTand 12.49 mV for SDS modified Na-MMT,indicating a greater surface potential of the modified nanoclay.The TGA showed greater weight loss for CTAB modified Na-MMT than that for Na-MMT,indicating the effective Na+ion exchange with alkyl amines.展开更多
文摘We investigated ^(50,52-54)Cr-induced fusion reactions for the synthesis of the superheavy element in the 104≤Z≤122 range.The cross sections produced in this investigation using ^(54)Cr projectiles were compared with those obtained in prior experiments.The estimated cross sections from this analysis are consistent with the findings of prior studies.From the current study,the predicted cross section was found to be 42fb at 236 MeV for ^(53)Cr+^(243)Am,23.2 fb at 236 MeV for ^(54)Cr+^(247)Cm,95.6 fb at 240 MeV for ^(53)Cr+248Bk,and 1.33 fb at 242 MeV for ^(53)Cr+250Cf.Consequently,these projected cross sections with excitation energy and beam energy will be useful in future Cr-induced fusion reaction investigations.
文摘In the present work the dynamic characteristics of Multilayer Polyurethane foam glass/fiber composite sandwich panels have been determined through Experimental Investigations. Using a Multilayer Polyurethane foam sandwich panel with rectangular cross-section, the natural frequencies, mode shapes and the damping ratio of sandwich panels were evaluated. Three types of boundary conditions were simulated namely, C-F-F-F (Clamped Free-Free-Free), C-F-C-F (Clam-ped-Free-Clamped-Free), C-C-C-C-(Clamped-Clamped-Clamped-Clamped). Experimental modal tests were conducted on sandwich panels with available polyurethane foam of densities 56 kg/m3, 82 kg/m3and 289 kg/m3.The traditional “strike method” has been used to measure vibration properties. The modal characteristics of the specimens have been obtained by studying their impulse response. Each specimen has been subjected to impulses through a hard tipped hammer which is provided with a force transducer and the response has been measured through the accelerometer. The impulse and the response are processed through a computer aided FFT Analyzing test system in order to extract the modal parameters. Finite Element modeling was carried out treating the facing and core as orthotropic with different elastic constants as recommended in the literature. The experimental results were validated with FEA and were found to be in good agreement.The results obtained through modal test on multilayer sandwich panels are presented. They indicate a significant variation in the dynamic parameters in case of multilayer sandwich panels for the same core density as compared to a monolayer sandwich panel.
文摘To demonstrate the influence of sliding friction of motion on a curve, a circular path is considered for simplicity on which a person slides from the highest point to the lowest point. A slide which represents a quadrant of radius 5 m and a person of mass 60 kg are considered for comparison in this paper. A Differential equation for motion considering the fact that the normal force depends both on the sin component of weight and also on the tangential velocity, is established and is solved using integrating factor method, and the motion is analysed for different surface roughness of the slide and is compared using superimposed graphs, also the limiting value of friction coefficient at which the person just exits the slide is determined. The correction factor for exit velocity with friction as compared with the exit velocity for zero friction is determined. The fraction of energy lost to friction at the exit is evaluated. The Variation of normal force with the position of the person on the slide is plotted for different surface roughness of the slide, and the position on the slide where the normal force or the force experienced by the person is maximum, is determined and hence its maximum value is evaluated for different surface roughness. For simplicity, a point contact between the body and the slide is considered.
文摘The aim of the research work was to numerically investigate the residual stresses induced between the layers of fiber metal laminate (FML) cylinder (glass/epoxy reinforced aluminum laminates) under buckling hydrostatic loading. For the analysis of buckling behavior of FML cylinders, various fiber orientations such as 0/90°, 60/30°, ±45° and ±55° and different FRP thickness of 1, 2, and 3 mm were considered. The aluminum cylinder of inner diameter 80 mm, length 800 mm and wall thickness 1 mm was modeled with SHELL281 element type and a total of 1033 elements were used for computing the induced residual stresses between the layers. The results show that magnitude of residual stresses between the layers decreased along the thickness from outer layer towards the inner layer in sine wave form. The maximum residual Von-Mises stress was at inner aluminum layer while the maximum residual radial stress was at the outermost layer of FML cylinder due to the inward pressure. Among all types of FML cylinder 0/90° fiber oriented FML cylinder exhibited the least radial stress and a maximum Von-Mises stress along the FRP thickness.
文摘Among different sources of alternate energy,wind and solar are two prominent and promising alternatives to meet the future electricity needs for mankind.Generally,these sources are integrated at the distribution utilities to supply the local distribution customers.If the power generated by these sources is bulk,then they are either integrated at the distribution/transmission level or may be operated in an island mode if feasible.The integration of these renewables in the power network will change the fault level and network topologies.These fault levels are intermittent in nature and existing protection schemes may fail to operate because of their pre-set condition.Therefore,the design and selection of a proper protection scheme is very much essential for reliable control and operation of renewable integrated power systems.Depending upon the level of infeed and location of the renewable integration,the protection requirements are different.For low renewable infeed at the distribution level,the existing relay settings are immune from any small change in the network fault current from new incoming renewables.However,bulk renewable infeed requires modification in the existing protection schemes to accommodate the fault current variation from the incoming renewables.For bulk penetration of the renewable,the requirement of modified/additional protection schemes is unavoidable.Adaptive relaying and non-adaptive relaying schemes are discussed in the literature for protection of power networks,which are experiencing dynamic fault currents and frequent changing network topologies.This article presents a detailed review of protection schemes for renewable integrated power networks which includes distribution,transmission and microgrid systems.The merits and demerits of these protection schemes are also identified in this article for the added interest of the readers.The visible scope of advance protection schemes which may be suitable for providing reliable protection for dynamic fault current networks is also explored.
文摘The Sodium Montmorillonite(Na-MMT)is not susceptible to polymer due to its organophilic character and low basal spacing.The primary objective of this study was to improve Na-MMT platelets separation by organically modifying it with cation and anion exchanges using Cetyl trimethyl ammonium bromide(CTAB)and Sodium dodecyl sulfate(SDS)respectively.Basal spacing,presence of functional groups,Zetapotential with particle size analysis and thermal stability of the Organomodified Na-MMT(OMMT)were characterized using XRD,FTIR,zeta-potential analyzer and TGA respectively.The basal spacing of CTAB modified OMMTincreased to 19.5Åfrom 11.0Åwhich corresponds to the basal spacing of Na-MMT.The SDS modified OMMT did not show any increase in the basal spacing.FTIR spectra of CTAB modified Na-MMT illustrated the attachment of CTAB functional groups to Na-MMT,while the same was absent in the case of SDS modified Na-MMT.The zeta-potential of Na-MMT shifted from–24.88 mV to 15.66 mV in the case of CTAB modified Na-MMTand 12.49 mV for SDS modified Na-MMT,indicating a greater surface potential of the modified nanoclay.The TGA showed greater weight loss for CTAB modified Na-MMT than that for Na-MMT,indicating the effective Na+ion exchange with alkyl amines.
