Showing papers on "Frustum published in 2003"

Dynamic mechanical properties in relation to adiabatic shear band formation in titanium alloy-Ti17

Abstract: A Split-Hopkinson Pressure Bar system was used to determine the dynamic mechanical properties in relation to the formation of adiabatic shear bands in titanium alloy-Ti17. Cylindrical and conical frustum specimens were impacted between the incident and transmitted bars. The experimental results showed that the dynamic yield stress (alpha(yd)) and impact strength (alpha(bd)) were both higher than the corresponding static values, and the failure was sensitive to the strain rate, but insensitive to the applied stress level. The critical strain rate for failure was epsilon(c) = 2000 s (-1). Microscopic examinations revealed that the break of specimen frequently occurred along the shear band. A hemicyclic shear band appeared on the transverse section of the conical frustum, while a straight shear band developed at the location of maximum shear stress and propagated along the trace of the maximum shear stress, which was determined by the analysis of the stress distribution. (C) 2003 Elsevier Science B.V. All rights reserved.

Surgical suspension system

Abstract: A suspension system (10) is disclosed for suspending lightheads (26), monitors (28, 30), cameras, or other medical apparatus from an overhead structure (12) at a selectable height. A drop tube (20) has a selected portion thereof surroundingly encompassed by a receiving element (42) that has a variable inside diameter substantially conforming to a frustum of a cone. A mounting plate (14) rigidly connects with the overhead structure (12) and with the receiving element (42). The mounting plate (14) has an opening through which an end of the drop tube (20) passes. A wedge-shaped element (48) has a variable outer diameter substantially conforming to a frustum of a cone. The wedge-shaped element (48) compressively inserts into the receiving element (42) and surroundingly encompasses the selected portion of the drop tube (20) to effectuate a compressive clamping of the selected portion of the drop tube (20) inside the receiving element (42).

Numerical simulation of conduction heating in conically shaped bodies

Abstract: A 2-dimensional energy balance approach was used to model temperature distribution in conduction heated conically shaped bodies. A numerical solution by finite differences to the second order partial differential equation for heat conduction served as basis for the model. The cone was divided into small volume elements. The inner elements were concentric rings of rectangular cross section while those at the side surfaces had triangular cross-sections. Energy balance equations for the volume elements were solved explicitly. Acrylic of known thermal properties was used to fabricate cones in 3 different geometries and sizes, varying from a frustum to a point cone. Every cone had 3 or 4 thermocouples (36 gauge, T type) inserted at different locations. Heat penetration tests were carried out in a water bath with constant and variable water temperatures. Experimental temperatures at different locations within the cones agreed well with temperatures predicted by the model. Use of the model to predict the location of the slowest-heating point or “cold point” under different processing conditions was also demonstrated.

Computing a View Frustum to Maximize an Object's Image Area

Abstract: This paper presents a method to compute a view frustum for a threedimensional object viewed from a given viewpoint, such that the object is completely enclosed in the frustum and the object's image area is also near-maximal in the given two-dimensional rectangular viewing region. This optimization can be used to improve the resolution of shadow and texture maps for projective texture mapping. Instead of doing the optimization in three-dimensional space to find a good view frustum, our method uses a two-dimensional approach. The basic idea of our approach is as follows. First, from the given viewpoint, a conveniently computed view frustum is used to project the three-dimensional vertices of the object to their corresponding two-dimensional image points. A tight two-dimensional bounding quadrilateral is then computed to enclose these two-dimensional image points. Next, considering the project ive warp between the bounding quadrilateral and the rectangular viewing region, our method applies a techni...

Lens array sheet and molding method

Abstract: To provide a lens array sheet capable of efficiently condensing diffuse light such as the light from a LED light source or EL light source. The lens array sheet comprises a transparent base material, a plurality of light-receiving sections each consisting of a transparent right frustum which is provided on the surface of the base material and is tapered outwardly from the base material, and a plurality of condensing lenses disposed on the back of the base material so as to face the respective light-receiving sections. The side face of the right frustum forms a taper angle larger than 0° and less than 15° with the central axial line of the right frustum, and an aspect ratio (H/D) which is a proportion of the height (H) of the right frustum to the minimum length (D) of the cut surface of the right frustum is larger than 0, and no more than 10.

Optimization of quality retention in conduction-heating foods of conical shape

Abstract: A cone frustum is an alternative shape for packaging thermally processed foods that can be useful in modeling the increasing number of microwaveable, ready-to-eat conical-shaped food containers seen on supermarket shelves. Thermal processing in a cone frustum can be optimized by using numerical models for heat transfer to predict temperature distribution profiles, together with thermal destruction kinetics of target organisms and nutrient/quality factors. Iso-lethality curves, showing combinations of process time and retort temperature that deliver equal lethality, were developed for each of three different cone frustum geometries (different dimensional proportions of major and minor diameters and height). Total volume average quality retention was determined for equivalent process time-temperature combinations for quality factors with assumed thermal degradation kinetic parameters (D and Z-values). Response of quality retention to the equivalent process combinations (designated by their retort temperature) revealed optimum process conditions that delivered maximum quality retention. The effect of kinetic parameters, thermal properties, and surface heat transfer coefficient on quality retention response to equivalent process conditions was also studied and compared with findings reported in the literature for the case of more traditional finite cylinder shapes.

Optimized Shadow Mapping Using the Stencil Buffer

Abstract: Shadow maps and shadow volumes are common techniques for computing real-time shadows. We optimize the performance of a hardware-accelerated shadow mapping algorithm by rasterizing the light frustum into the stencil buffer, in a manner similar to the shadow volume algorithm. The pixel shader code that performs shadow tests and illumination computations is applied only to the pixels that are inside the light frustum. We also use deferred shading to further limit the operations to visible pixels. Our technique can be easily plugged into existing applications, and is especially useful for dynamic scenes that contain several local light sources. In our test scenarios, the overall frame rate was up to 2.2 times higher than for our comparison methods.

Differential housing with integrated ring gear

Abstract: A method is disclosed for making a differential housing having a ring gear integrally formed therein. The method includes the steps of forging a conical frustum from a steel rod; deforming the frustum between upper and lower die halves of a tool to produce a differential housing having an annular rim; and forging a plurality of teeth in the annular rim defining the rim gear.

Probe for a body cavity

Abstract: A medical probe for collecting signals from a body cavity having a profile which is a combination of an outside frustum shape and the multiple surface cavities or indentations situated on the probe outer surface. The probe outer surface when enveloped by a thin probe cover material forms air pockets, thus reducing thermal conductivity across the probe walls and minimizing negative effects of the lateral heat transfer.

Accurate and efficient prediction of coverage map in an office environment using frustum ray tracing and in-situ penetration loss measurement

Abstract: Results of wideband (125 MHz) received power and rms delay spread measurements at 5.24 GHz in a practical office environment are compared with the prediction utilizing the frustum ray tracing technique (FRTT) and detailed penetration loss measurement of major blocking objects on site. Penetration loss was measured for an object at different incident angle at different surface locations. Direct waves through walls were separated from unwanted waves in time and in space by system and directional horn antennas. A periodical variation of penetration loss as a function of surface location was observed for objects with inhomogeneous internal structure. A model was developed to approximate mean penetration loss at each incident angle for such objects. Using this model, an excellent agreement with the measured results was obtained by the FRTT without post tuning of simulation parameters.

Decorative tree stand

Abstract: A portable tree stand has a lower surface adapted for resting on a substantially level plane and an upper surface comprising a bowl-shaped depression provided with an upstanding rigid pin assembly being located in the bowl depression, with the pin assembly being integral of a central platform component of the bowl inner surface. The sidewalls of the stand extend radially outward to the lower most periphery thereof and present an external conical frustum skirt.

Approximating 3D general sweep boundary using depth-buffer

Abstract: This paper presents a practical technique for approximating the boundary surface of the volume swept out by three-dimensional objects using the depth-buffer Objects may change their geometries and orientations while sweeping The sweep volume is approximated as a union of volume elements, which are just rendered inside appropriate viewing frusta of virtual cameras and mapped into screen viewports with depth-buffer From the depth of each pixel in the screen space of each rendering, the corresponding point in the original world space can be computed Appropriately connecting these points yields polygonal faces forming polygonal surface patches approximately covering some portion of the sweep volume Each view frustum adds one or more surface patches in this way, and these presumably overlapped polygonal surface patches approximately enclose the whole sweep volume These patches may further be processed to yield non-overlapped polygonal surfaces as an approximation to the boundary of the original 3D sweep volume

Radar system with a rotating antenna system

Abstract: A radar antenna system comprises a wheel, cone or frustum having an axis. The wheel, cone or frustum has a circumferential portion adapted to engage at least one path disposed on a platform for revolving the radar array about the platform. A radar array is mounted on the wheel, cone or frustum, with the axis normal to a face of the radar array. The wheel, cone or frustum rotates about the platform as the radar array revolves around the platform during operation.

Transformed seamless can and its manufacturing method

Abstract: PROBLEM TO BE SOLVED: To provide a transformed seamless can that is hard to buckle when load is applied in the direction of its body height, and that does not buckle from a tapered part by axial load at the time of wind-fastening. SOLUTION: The transformed seamless can 1 comprises a body part 2 that is constituted of an upper part 2a having a cylindrical form and a lower part 2b having a form of a frustum of a reverse cone, with a thick-wall part 2f being provided at the border portion between the upper part 2a and the lower part 2b or in the vicinity thereof. The can is also characterized in that the lower part 2b is bent inward or in a tapered state.

Frustum filter used for separation of cation and anion exchange resins

Abstract: A frustum filter used for separation of cation and anion exchange resins, which is used in condensate water polishing system or apparatus, wherein said frustum filter comprises a microporous filtering net body ( 1 ) which is formed by sintering a mixture of silicon carbide grains and a binder, said net body being provided with a plurality of micropores, the diameter of said micropores being in a range of 50-300 micron, said filtering net body ( 1 ) being shaped as an inverted truncated cone and its maximum diameter being in a range of 50-200 cm, the angle between a inner tapered face and a horizontal plane being in a range of 15°-30° and the thickness of said filtering net body being in a range of 2 cm-14 cm. Some reinforcing steel bars which have the property of high temperature resistance are embedded in said filtering net body( 1 ) in advance. A steel ring ( 6 ) welded at the housing ( 2 ) is fixed on the external circumference of said filtering net body ( 1 ). This invention has the following advantages: it can distribute evenly water and has high strength; it can not be blocked easily and will not create dead zones when filtration; the product of the invention has high strength and cannot be deformed easily over the prior art; it also has the properties of strong acid fastness, strong alkali fastness, high temperature resistance, oxidation resistance.

Hyperfrequency oscillator with very high stability

Abstract: The oscillator of the invention comprises a one-piece dielectric resonator in the form of a right cylinder frustum hollowed out at mid-height along chords of its cross section, so as to leave a central core and two lateral flanges, the drillholes having symmetry of order N, where N≧4, at least the plane faces of the cylinder being covered with a superconducting material, the resonator being placed in a cryogenic chamber and being connected to an amplifier via optimized couplings, and the tuning of the resonator being done by a magnetic field and a phase loop.

Plant pot is shaped like frustum of square pyramid and is assembled from cross-shaped blank made from thin, hydrophobic sheet

Abstract: The plant pot is shaped like a frustum of a square pyramid. It is assembled from a cross-shaped blank made from thin, hydrophobic sheet, preferably recycled plastic sheet.

GPS antenna for submarine towed buoy

Abstract: An apparatus including a gimbal and an antenna with a hollowed frustum having a closed end and an open end. The antenna includes a feed stem at the closed end extending as an internal rod into the hollowed frustum. The opposite end of the rod connects to a receiver section extending from an edge of the open end beyond a longitudinal axis of the antenna. The antenna is supported by the gimbal attachable to a container suitable for towing. A pivot at the open end in relation to the center-of-gravity of the frustum allows a swinging arc in relation to the attached gimbal in that the frustum moves by gravity toward the axes of the gimbal such that the receiver section maintains a facing position to the force of gravity.

Optimization of liquid cooling fins in microelectronic packaging

Abstract: The present study investigates the heat transfer from a fin of the combination of cone and frustum of a cone immersed in boiling FC-72. The temperature distribution within the fin is determined with the help of a three-dimensional finite element computation technique using linear axisymmetric elements. From the temperature distribution, the fin base temperature gradients at various base temperature excesses are obtained. The numerical results are found to be in good agreement with published experimental data. Parametric studies have been carried out using this numerical method. An artificial neural network is used to consolidate additional data from the parametric studies. The genetic algorithm is then applied to the case of a fixed volume fin, in order to determine the dimensions which optimize the heat transfer per unit volume. It is observed that the heat transfer per unit volume decreases with fins of increasing volumes. Conclusively, the technique used in the analysis is able to provide a fast and ac...

Tubular light has conical or conical frustum-shaped reflector within tubular outer body whose longitudinal axis essentially coincides with longitudinal axis of outer body

Abstract: The tubular light has a transparent tubular outer body (12), at least one light source (20) for emitting light rays into the interior of the outer body and at least one conical or conical frustum-shaped reflector (16) within the tubular outer body whose longitudinal axis essentially coincides with the longitudinal axis of the outer body.

Spirally expanded bead disk pile

Abstract: The utility model belongs to a precast pile used in building, bridge and other works. The proposed rotating and squeezing pile comprises a pile body (1) and bearing discs (2), and one or a plurality of bearings discs, which are formed by rotating and squeezing are composed of an upper frustum and a lower reversed frustum. The rotating and squeezing pile proposed by the utility model has the advantages of regular forming and high bearing capacity, and the rotating and squeezing pile can avoid the disadvantages of landslide and high cost.

Nijmerical simulation of conduction heating in conically shaped bodies

Abstract: A 2-dimensional energy balance approach was used to model temperature distribution in conduction heated conically shaped bodies. A numerical solution by finite differences to the second order partial differential equation for heat conduction served as basis for the model. The cone was divided into small volume elements. The inner elements were concentric rings of rectangular cross section while those at the side surfaces had triangular cross-sections. Energy balance equations for the volume elements were solved explicitly. Acrylic of known thermal properties was used to fabricate cones in 3 different geometries and sizes, varying from a frustum to a point cone. Every cone had 3 or 4 thermocouples (36 gauge, T type) inserted at different locations. Heat penetration tests were carried out in a water bath with constant and variable water temperatures. Experimental temperatures at different locations within the cones agreed well with temperatures predicted by the model. Use of the model to predict the location of the slowest-heating point or "cold point under different processing conditions was also demonstrated.