Search

The strength and stiffness characteristics are important parameters in the design of metal structure of gantry crane. In this paper, the modeling of a gantry crane before and after reconstruction was performed by using Finite Element Method, and the strength and static stiffness of the gantry crane were analyzed. The results show that the insufficient stiffness of the reconstructed gantry crane in the shaking direction causes its laterodeviation. A strengthened method was determined after comparison of four reinforcement measures. The present results can provide an importantly theoretical basis for the reconstruction or strengthening of gantry cranes.

One of the emphases of this paper was the enhancement of drag prediction as well as the decomposition of drag into its physical components. The drag-prediction capability of the improved WBVS code for transonic flow about wing/body combination was verified by two approaches, code to code and code to experiment. The good agreements indicate that the wing body viscous has the capability to assess the aerodynamic performance in the supercritical wing design for civil transport aircraft. Another task of the present study was to redesign a supercritical wing for a new regional jet aircraft by employing the improved code as an analysis tool for wing/body combination. To accomplish this, a geometry-modifying technique was employed to gradually improve the upper- and lower-surface shapes of wing sections

A numerical method has been developed for computing the e owe eld around advanced transport aircraft with wing-mounted nacelles. The method is based on a multiblock point-matched grid-generation approach combined with zonal solving strategy for complex e owe eld. In this study the e owe eld is divided into a number of nonoverlapped blocks by a cutout technique. H-type grids are generated independently in each block using an elliptic grid-generation method, in which the control of the grid quality is accomplished by the forcing-function technique of Hilgenstock. The e owe eld is simulated by solving the Euler equations. An explicit three-stage Runge ‐Kutta algorithm based on the Jameson’ s e nite volume scheme for the Euler equations has been developed that is applied to the multiregion H-type grids. The present method has been applied to isolated powered engine nacelles and complex transport aircrafts consisting of low-wing/fuselage with wing-mounted pylon/nacelles. On the wing surfaces the viscous effects are simulated by the employment of the viscous/inviscid interaction (VII) technique of two-dimensional strip boundary layer. In this study the boundary-layer program uses an integral method to calculate turbulent boundary layers. With the concept of an equivalent inviscid e ow, the model of blowing velocity is employed in the VII technique. The effect of the boundary layeron the outer inviscid e ow is represented through a transpiration boundaryconditionderived from theboundary-layerparameters.Themain benee tofthistreatment isthatthegridisgeneratedonlyonceinoverallcomputingprocedure.Computationalresultsandcomparisonswith experimental data are presented. The good agreement indicates that the present method is effective in predicting the e ows about powered engine nacelles and/or complex transport aircrafts.

The panel method was used for the numerical calculations in this study. The propeller vortex system rotating with its blades, and the steady horseshoe vortex system distributed on the aircraft surface were used as the mathematical model. Neumann boundary conditions were satisŽ ed at the panel control points of the blade and the aircraft panel to achieve coupling of propeller slipstream with the whole  owŽ eld of the aircraft. At each corresponding azimuth angle of the propeller, pressure coefŽ cients and induced velocities by the two vortex systems at the panel control points were calculated; from this, the average aerodynamic characteristics of the aircraft in one revolution period were obtained. The contraction effect of the three-dimensional propeller slipstream and its in uence on the  owŽ eld were considered in the computation. Results of numerical examples showed that the slipstream had a signiŽ cant effect on aircraft lift characteristics such as  ap de ecting, resulting in relatively large changes of the aircraft moment performance. Numerical results were in good agreement with the experimental data. The method presented here is suitable for both singleand multiple-propeller aircraft.

Gene therapy provides a promising approach to curing diabetes. However, an effective route for islet-specific targeting has yet to be established. Toward this end, the pancreatic blood circulation system in Balb/c mice was determined by the injection of rhodamine-containing beads. The efficiency of islet targeting was then measured by the injection of adenoviral vectors carrying a green fluorescence gene via the celiac trunk (C.T.). The results showed that >95% of islets and about 60% of β cells within the pancreatic body and tail could be labeled 3 days after surgery. α-Cell labeling was not as efficient, whereas labeling of nonendocrine tissues was barely detectable. For proof of principle, adenoviral vectors carrying a Sirtuin transgene were injected similarly to test the islet protection effect in the streptozotocin (STZ)-induced type 1 diabetic model. The results demonstrated that overexpression of Sirtuin in STZ-treated mice reduced the level of β-cell death and extent of glucose intolerance. This study reports on efficient islet-specific targeting by using adenoviral injection. This procedure could be invaluable to the treatment of diabetes and the study of islet biology.

International audience