In the present study, we have obtained a new analytical solution of combined Einstein-Maxwell field equations describing the interior field of a ball having static spherically symmetric isotropic charged flu...In the present study, we have obtained a new analytical solution of combined Einstein-Maxwell field equations describing the interior field of a ball having static spherically symmetric isotropic charged fluid within it. The charge and electric field intensity are zero at the center and monotonically increasing towards the boundary of the fluid ball. Besides these, adiabatic index is also increasing towards the boundary and becomes infinite on it. All other physical quantities such as pressure, density, adiabatic speed of sound, charge density, adiabatic index are monotonically decreasing towards the surface. Causality condition is obeyed at the center of ball. In the limiting case of vanishingly small charge, the solution degenerates into Schwarzchild uniform density solution for electrically neutral fluid. The solution joins smoothly to the Reissner-Nordstrom solution over the boundary. We have constructed a neutron star model by assuming the surface density . The mass of the neutron star comes with radius 14.574 km.展开更多
This paper describes the experimental method for evaluating the flight trajectory and the aerodynamic performance of a kicked non-spinning soccer ball. The flight trajectory measurement is carried out using the digita...This paper describes the experimental method for evaluating the flight trajectory and the aerodynamic performance of a kicked non-spinning soccer ball. The flight trajectory measurement is carried out using the digital image analysis. A centroid method and a template matching method are tested for the flight trajectory analysis using the artificial images generated by the data of a free-fall experiment. The drag coefficient obtained by the centroid method is better suited for the sports ball experiment than that by the template matching method, which is due to the robustness of the centroid method to the non-uniform illumination. Then, the flight trajectory analysis is introduced to a kicked experiment for a non-spinning soccer ball. The experimental result obtained from the stereo observation indicates that the S-shaped variation is found in the three-dimensional flight trajectory and in the side force coefficient during the flight of the non-spinning soccer ball.展开更多
The methods of dividing balls equally among ball bearings to install the bearing retainer is briefly introduced in this paper, and the insufficiency of traditional methods is pointed out. A novel kind of non-contact t...The methods of dividing balls equally among ball bearings to install the bearing retainer is briefly introduced in this paper, and the insufficiency of traditional methods is pointed out. A novel kind of non-contact type of dividing ball method is proposed, according to the principle theory.展开更多
In the present investigation of a spherically symmetric electrically neutral anisotropic static fluid, we present a new solution of the Einstein’s general relativistic field equations. The solution shows positive fin...In the present investigation of a spherically symmetric electrically neutral anisotropic static fluid, we present a new solution of the Einstein’s general relativistic field equations. The solution shows positive finite central pressures, central density and central red shift. The causality condition is obeyed at the centre. The anisotropy parameter is zero at the center and monotonically increasing toward the surface. The adiabatic index is also increasing towards the surface. All the other physical quantities such as matter-energy density, radial pressure, tangential pressure, velocity of sound and red shift are monotonically decreasing towards the surface. Further by assuming the surface density , we have constructed a model of massive neutron star with mass 2.95 with radius 18 km with all degree of suitability.展开更多
Reynolds equation of a ball impacting and rebounding a lubricated surface covered by non Newtonian lubricant oil is derived, and numerical analysis are done.
为验证绒囊流体在含高矿化度地层水地层中稳油控水效用,在温度120℃、围压15 MPa、回压1.5 MPa条件下,采用恒流速法测定绒囊流体封堵前后,含不同矿化度盐水和煤油的人造砂岩柱塞稳定流动渗透率和注入压力变化。实验结果表明,0.1 m L/mi...为验证绒囊流体在含高矿化度地层水地层中稳油控水效用,在温度120℃、围压15 MPa、回压1.5 MPa条件下,采用恒流速法测定绒囊流体封堵前后,含不同矿化度盐水和煤油的人造砂岩柱塞稳定流动渗透率和注入压力变化。实验结果表明,0.1 m L/min恒定流速下,绒囊流体封堵前后,含Fe2＋＋Ca2＋＋Mg2＋矿化度分别为1×104 mg/L、10×104 mg/L、20×104 mg/L盐水岩心驱替压力由0.46~0.63 MPa升至1.39~2.23 MPa,封堵能力提高205.83%~262.64%;渗透率140.82~193.30 m D降至66.96~109.85 m D,损失率43.15%~52.53%。以煤油模拟地层原油,相同条件下测定封堵前后效果,驱替压力0.48~0.52 MPa升至0.51~0.55 MPa,增幅5.83%~8.08%;渗透率232.05~272.52 m D降至211.09~249.25 m D,损失率2.26%~4.51%。在地层水矿化度8×104 mg/L、4×104 mg/L的Y井和Z井实施绒囊流体稳油控水,通过提高泵次、深抽等工艺,油井产水量分别降低46.38%、15.99%,产油量提高6 200%、180%。研究和应用表明,绒囊流体抗高矿化度堵水体系能够实现稳油控水。展开更多
文摘In the present study, we have obtained a new analytical solution of combined Einstein-Maxwell field equations describing the interior field of a ball having static spherically symmetric isotropic charged fluid within it. The charge and electric field intensity are zero at the center and monotonically increasing towards the boundary of the fluid ball. Besides these, adiabatic index is also increasing towards the boundary and becomes infinite on it. All other physical quantities such as pressure, density, adiabatic speed of sound, charge density, adiabatic index are monotonically decreasing towards the surface. Causality condition is obeyed at the center of ball. In the limiting case of vanishingly small charge, the solution degenerates into Schwarzchild uniform density solution for electrically neutral fluid. The solution joins smoothly to the Reissner-Nordstrom solution over the boundary. We have constructed a neutron star model by assuming the surface density . The mass of the neutron star comes with radius 14.574 km.
文摘This paper describes the experimental method for evaluating the flight trajectory and the aerodynamic performance of a kicked non-spinning soccer ball. The flight trajectory measurement is carried out using the digital image analysis. A centroid method and a template matching method are tested for the flight trajectory analysis using the artificial images generated by the data of a free-fall experiment. The drag coefficient obtained by the centroid method is better suited for the sports ball experiment than that by the template matching method, which is due to the robustness of the centroid method to the non-uniform illumination. Then, the flight trajectory analysis is introduced to a kicked experiment for a non-spinning soccer ball. The experimental result obtained from the stereo observation indicates that the S-shaped variation is found in the three-dimensional flight trajectory and in the side force coefficient during the flight of the non-spinning soccer ball.
文摘The methods of dividing balls equally among ball bearings to install the bearing retainer is briefly introduced in this paper, and the insufficiency of traditional methods is pointed out. A novel kind of non-contact type of dividing ball method is proposed, according to the principle theory.
文摘In the present investigation of a spherically symmetric electrically neutral anisotropic static fluid, we present a new solution of the Einstein’s general relativistic field equations. The solution shows positive finite central pressures, central density and central red shift. The causality condition is obeyed at the centre. The anisotropy parameter is zero at the center and monotonically increasing toward the surface. The adiabatic index is also increasing towards the surface. All the other physical quantities such as matter-energy density, radial pressure, tangential pressure, velocity of sound and red shift are monotonically decreasing towards the surface. Further by assuming the surface density , we have constructed a model of massive neutron star with mass 2.95 with radius 18 km with all degree of suitability.
文摘Reynolds equation of a ball impacting and rebounding a lubricated surface covered by non Newtonian lubricant oil is derived, and numerical analysis are done.
文摘为验证绒囊流体在含高矿化度地层水地层中稳油控水效用,在温度120℃、围压15 MPa、回压1.5 MPa条件下,采用恒流速法测定绒囊流体封堵前后,含不同矿化度盐水和煤油的人造砂岩柱塞稳定流动渗透率和注入压力变化。实验结果表明,0.1 m L/min恒定流速下,绒囊流体封堵前后,含Fe2＋＋Ca2＋＋Mg2＋矿化度分别为1×104 mg/L、10×104 mg/L、20×104 mg/L盐水岩心驱替压力由0.46~0.63 MPa升至1.39~2.23 MPa,封堵能力提高205.83%~262.64%;渗透率140.82~193.30 m D降至66.96~109.85 m D,损失率43.15%~52.53%。以煤油模拟地层原油,相同条件下测定封堵前后效果,驱替压力0.48~0.52 MPa升至0.51~0.55 MPa,增幅5.83%~8.08%;渗透率232.05~272.52 m D降至211.09~249.25 m D,损失率2.26%~4.51%。在地层水矿化度8×104 mg/L、4×104 mg/L的Y井和Z井实施绒囊流体稳油控水,通过提高泵次、深抽等工艺,油井产水量分别降低46.38%、15.99%,产油量提高6 200%、180%。研究和应用表明,绒囊流体抗高矿化度堵水体系能够实现稳油控水。
