Showing papers on "Contact area published in 1983"

A study of the advancing interface

Abstract: A molecular model has been developed which predicts the dependence of the dynamic contact angle upon the capillary number when a liquid moves to displace a gas. As a basis for this analysis we have assumed that molecules at the contact line between the advancing liquid and the solid substrate move forward by two different mechanisms. One involves the diffusion of liquid molecules across the solid substrate. This process is dominant when the dynamic contact angle is less than 120°, and the rate of surface diffusion increases with increasing values of the dynamic contact angle. The other process involves a “tank tread” motion of the liquid molecules normal to the solid substrate; this latter mechanism predominates when the dynamic contact angle is 180°. At contact angles between 120 and 180°, both processes come into play. From the model used in this analysis one finds that there are several molecular parameters which have some influence on the relationship between the dynamic contact angle and the capillary number. Although the effect of these parameters may be secondary in nature, it is likely that a universal correlation for the dynamic contact angle which is valid for all fluids and solid substrates must include these variables along with the capillary number and the static contact angle.

Determination of stiffness and other joint properties from roughness measurements

Abstract: The measurement of surface profiles is presented as a useful and simple approach to classifying statistically the essential features of rock joints. After introducing the reader to some existing analytical joint contact models for normal loading, a discrete numerical technique is developed. Using this technique the mechanical behaviour of a number of different slate joints is examined. The functional relationships between nominal stress, stiffness, true contact area and initial aperture are shown, for this class of joints, to be surprisingly simple. Experimental evidence is used to substantiate the numerical results. From the point of view of in-situ joint stiffness and hydraulic conductivity, numerical predictions seem feasible provided the degree of “mating” at some known stress level can be determined.

Double self-aligned fabrication process for making a bipolar transistor structure having a small polysilicon-to-extrinsic base contact area

Abstract: A bipolar transistor device is disclosed having a structure wherein a layer of insulating material extends over and covers the structure substrate up to the region of the extrinsic base around the emitter. A very small area conductive base contact is provided to the extrinsic base, and a protective wall of insulating material is located on the sidewall of the base contact to isolate it from the emitter contact. This structure is made possible by a fabrication process incorporating a double-self-alignment technique wherein the base is self-aligned to a window in the insulating material and the emitter is self-aligned to the base.

Low-velocity impact response of laminated plates

Abstract: An analysis is presented to predict the response of anisotropic laminated plates to low-velocity impact by a rigid object. Transverse shear deformation in the plates is accounted for using Mindlin's theory and the governing equations are solved using Fourier integral transforms, assuming infinite planform dimensions for the plate. The contact area is assumed to vary with time, and the complex contact problem is replaced by a loading history that is based on available experimental data from instrumented impact tests. Computed plate response is used to predict initial failures, including back surface fiber/matrix failures, directly below the impact site and internal delaminations. Analytical predictions are shown to compare well with available experimental results and finite element solutions.

Monopolar, bipolar and/or hybrid membrane cell

Abstract: Monopolar, bipolar, and highbrid filter press electrolytic cells for electrolytic processes utilizing a novel method of introducing and removing electrical energy. The invention contemplates a novel low pressure, high surface contact area connecting means for joining the anode element and cathod element of electrode assemblies. The invention also contemplates a low pressure, high surface contact area contact of the current distributor member to the back plate.

A Simplified Theory for Non-Hertzian Contact

Abstract: (1983). A Simplified Theory for Non-Hertzian Contact. Vehicle System Dynamics: Vol. 12, No. 1-3, pp. 43-45.

An Experimental Study of the Hertzian Contact of Surfaces Covered by Soft Metal Films

Abstract: This paper describes an investigation of the static contact between a steel ball and a lead-plated steel flat. Both the normal approach of the surfaces and their area of contact have been measured as functions of normal load and the thickness of the lead film. It is shown that, at high loads where the radius of contact is greater than five times the film thickness, all the coated surfaces behaved elastically, and the elastic properties of the coated surfaces were identical to those of the uncoated steel. At lower loads and high film thicknesses, the films deform plastically. The transition from elastic to plastic deformation occurred when the radius of the contact area was approximately five times the film thickness. Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference in Washington, D. C., October 5–7, 1982

Stresses around pin-loaded holes in composite materials

Abstract: Stresses have been calculated for infinite orthotropic plates with a circular hole loaded by a perfectly fitting rigid pin with arbitrary load direction. The effect of friction at the interface between pin and plate material is evaluated. The calculations are based on the analytical method of complex stress functions. A numerical approach was used for satisfying the displacement boundary conditions of the contact area between pin and hole. Stress concentration factors based on the nominal bearing stress are presented graphically for three carbon fibre reinforced plastic laminates. A quadratic failure criterion was used to predict the bearing stress at which first significant damage occurs. The results indicate that the presence of friction has a significant influence on the stress distribution.

Planar electronic filter element and a connector embodying such a filter

Abstract: A planar electronic filter has at least two dielectric plates with a ground plate between them and a plurality of parallel spaced electrodes on the outer surface of each plate. A contact area on at least one end surface connects with the ground plate. Usually contact pins are mounted, as by soldering, on the electrodes, a pin on each electrode, with the ends of the pins extending beyond the sides of the plates. The pin ends may be of male or female form, or can be formed for solder or wire wrapping attachment of conductors. The filter is generally mounted in a housing and it can be arranged that contact pins are not mounted on the electrodes but contact members in the housing make direct contact with the electrodes. A connector embodying the filter can comprise one or two housings. One housing can insert into the other and make contact with the filter.

Simulation of closure: effects on crack detection probability and stress distributions

Abstract: It is well known that partial contact of two rough crack surfaces will lead to transmission of an acoustic signal across the crack, thus giving rise to a reduced probability of detection (POD). To explore the effects and consequences of such partial contact, impression experiments—using small spheres—have been performed to determine the effects of contact area on the amplitude transmitted. The results have been compared with a theory described elsewhere in these Proceedings. Based on the experimental results it will be speculated that the residual stress field responsible for the crack closure may be calculated based on a determination of the size and separation of the contact areas.

Strength of glass ceramic S0115M and its joints based on optical contact

Abstract: 1 Breaking strength for joints based on optical contact with a contact area of 680 mm2 is 111 MPa for rectangular cross section specimens Specimens with an annular configuration and a contact area of 150 mm2 have the highest ultimate strength σf=245 MPa 2 Ultimate strength in axial tension and compression for cylindrical specimens made of optical glass ceramic with high microroughness of the lateral surfaces RZ≤063 μm is 591 and 2008 MPa respectively, and this exceeds the ultimate breaking strength of joints based on optical contact with an area of 150 mm2 by factors of 24 and 820 3 In absolutely brittle materials of the optical glass ceramic type forces of mutual attraction operate in annular crack zones predicted by the Leonov-Panasyuk model for the limiting condition, and they promote closing together of the crack sides It may be assumed that the magnitude of these mutual attraction forces for the crack sides is not less than the breaking stress for joints based on optical contact established in this way 4 In critical articles of the shell type made of glass and glass ceramic loaded by external hydrostatic pressure, it is possible for cracks to develop during operation It is not possible to detect these cracks visually due to closing together of the sides after removal of a tensile load In order to provide reliable operation of similar articles there is considerable practical interest in the search for experimental methods making it possible to reveal cracks in these objects

Indentation-Debonding Test for Adhered Thin Polymer Layers

Abstract: The indentation-debonding test is basically a nondestructive test for checking the adherence of thin polymer films to hard substrates (such as epoxy film adhered to copper). A small pointed indenter is pressed to the surface in the normal direction. The tensile stresses arising in the bond outside the contact area may exceed the limiting value and debonding would then take place. Observation of this phenomenon is often facilitated by the appearance of Newton’s rings created by the diffraction of light passed through and reflected from the debonded film. Mechanical analysis of the deforming polymer film is based on the computation of displacements of a thin plate segment confined between the rim of the indentation and the edge of the debonded area. It is experimentally found that the radial bending strain in the film limits the adherence, i.e., determines the onset of “peeling”. Cases of pure interfacial debonding have been treated, and experimental data are described, for a wide variation of parameters.

Electrical analogy of hydraulic flow through rock fractures

Abstract: Electrical analogy is used to study the influence of contact areas on the hydraulic flow through rock fractures. The investigation has shown that in the case of radial flow the location of contact zones, as well as the total contact area, influences the flow rate. It is also demonstrated that when injection tests are conducted in boreholes, where the fracture close to the borehole is partially plugged by loose particles or other debris, the flow rate may be substantially underestimated.

Method and apparatus for producing a fasciated yarn

Abstract: A method and an apparatus for producing a fasciated yarn, utilizing an air nozzle for false twisting a fiber bundle, provided with a fiber passage comprising an inlet portion, a small channel, and a large channel, characterized by the provision of at least a contact area in the inlet portion and/or the upstream region of the small channel. During the spinning operation, the fiber bundle is forced against the contact point, and, as a result, a twist imparted by a vortex can be effectively suppressed so that it does not ascend toward the upstream region. Also, since ballooning can be suppressed by the contact point, the size of the small channel can be increased, resulting in the sufficient suction air in the inlet portion.

Fixed-bed catalyst

Abstract: PURPOSE:To obtain a fixed bed catalyst having large contact area between a fluid and the catalyst, and capable of smoothly passing the fluid through and dispersing it into the catlyst, by using a pack of bulky activated carbon fibers are a carrier. CONSTITUTION:Activated carbon fibers impregnated with an activated component, such as Ru, of a catalyst entwined each other, for example, felt of acrivated carbon fibers is used for forming an intended fixed bed catalyst. This felt persists at >=1kg/cm compression force. Therefore, even if a fluid is forced to flow by pressure, it causes no appreciable deformation, retaining bulkiness, and spaces among the fibers, permitting smooth flow of the fluid with low resistance. As a result, large contact area between the fluid and the catalyst, and large contact area between liquid wetting the fibers and gas can be retained stably. In addition, an amt. of activated component of the catalyst to be held on the carrier is usually 0.01-10wt%.

Cross roller way unit

Abstract: PURPOSE:To make a guide body light, and minimize the guide resistance, by composing the guide body of the roller in an unloaded zone from a thin plate having an upper and a lower horizontal edge. CONSTITUTION:A central guide body 14 and an edge guide body 15 include upper guide plates 19 and lower guide plates 20, and the upper guide plate 19 is at the edge 21 in sliding contact with an end surface 23 of one of the rollers 7 positioned at an upper and outer side of the rollers 7 and also in sliding contact with a circumferential surface 24 of the adjacent roller 7, while the lower guide plate 20 is at the edge 22 in sliding contact with an end surface 23a of one of the rollers 7 positioned at the lower and outer side of the rollers 7 and also in sliding contact with a circumferential surface 24a, so that the roller 7 in an unloaded zone is guided. The central guide plate 14 and the end guide plate 15 are made of thin steel plates and are light-weight. As they are in sliding contact with the rollers at the edge, the contact area is small and the guide resistance is small.

A static monolithic cylindrical honeycomb structure with large contact surface

Abstract: not available for EP0025980Abstract of corresponding document: US4343354The invention relates to a static cylindrical monolithic cellular structure with a large contact area, said structure being used in particular for a static heat exchanger and including a plurality of parallel ducts. Its general organization is essentially cylindrical, and the ducts are defined by radial walls (10) and circumferential walls (11). Said ducts form groups for conveying different fluids with the groups being in an essentially radial configuration, i.e, with groups for conveying different fluids at least some of the radial type walls constituting the boundaries between different fluid flows. Application in particular to static exchangers and to filters.

A pneumatic tire

Abstract: A tread for a pneumatic tire comprising a plurality of circumferentially extending grooves 12, the grooves comprising alternating wide and narrow portions 16, 14. The grooves are disposed such that the net contact area in the footprint of the tire during rotation is substantially constant and the net contact area in the footprint of the tire being at least seventy percent (70%).

High Reliability Absolute Semiconductor Pressure Sensor

Abstract: This paper describes an absolute semiconductor pressure sensor suitable for the engine control systems in automobiles. Using the passive (electrically nonconnected) side of a sensor chip as the pressure interface, it has good pressure media compatibility. But it requires a pedestal with a pressure inlet hole and a larger contact area for good sealed, vacuum reference, since the larger contact area causes a larger temperature shift of the offset voltage due to thermal stress. We have analyzed the thermal stress by the finite element method and have designed a lower, tubular pedestal with a groove which has isolated the sensor chip from the thermal stress more effectively. As a result, the sensor chip has been assembled in a standard TO-5 package and a temperature shift of the offset voltage within plus or minus 1% error of FS (Full Scale) without temperature compensation in the temperature range of minus 30 deg C to 100 deg C has been realized.

Twin roll type casting and rolling machine

Abstract: PURPOSE:To prevent the fluctuation in the thickness of an ingot and the considerable fluctuation in rolling down force by providing limiting plates in the well part for molten metal formed of two rolls, and controlling the contact area of the molten metal with the rolls. CONSTITUTION:If limiting plates 5, 5' are moved along the surfaces of rolls 1, 1' and are held in prescribed positions, the plates 5, 5' cover the surfaces of the rolls 1, 1' and the tips thereof are dipped into a well part 3. As a result, the contact length lc between molten metal 2 and the rolls 1, 1' is controlled. Thereupon, the contact length lc is changed by moving and adjusting the plates 5, 5' according to the volume of the molten metal in the part 3, whereby the fluctuation in the thickness of the solidified shell owing to slight fluctuations in casting conditions, is corrected and the always stable operations are accomplished.

Experimental and finite element study of a standing torus under normal and tangential loads

Abstract: The effect of a combined external load consisting of a normal component and a tangential braking force applied to an inflated torus is addressed. Experimental results obtained by photographic study of the contact area between the torus and load plate are presented as well as measurements of the vertical and horizontal displacement of the torus under load. A numerical procedure for displacement analysis is developed in which the finite element program STAGS (Structural Analysis of General Shells) is used in an iterative manner to produce a flat, horizontal footprint surface under force loading. The redistributed force distribution obtained by the iterative process is displayed along with computed meridional and circumferential stresses. Finally, an extension of the iterative method is introduced which eliminates the need to experimentally determine the footprint area.

Method of constructing heavy floating structure

Abstract: PURPOSE:To shorten a horizontal trunk and reduce its cost by forming a required number of wells at the contact area of a number of floating bodies that are to be adjacent to one another and sequentially joining the contact area of both floating bodies partially using these wells. CONSTITUTION:Wells 26 to 31 are formed at the contact areas of a number of floating bodies 2 that are adjacent to one another. Each of the floating bodies 2 is floated on the water level, pulled nearer, and is brought in contact with each other. When the contact areas are joined, a horizontal trunk 34 whose upper surface is opened and in which the sealing section is fit is brought in contact with the lower surface of each of the floating bodies 2 and a vertical trunk 43 with the same structure that is opened at the contact position of each of the floating bodies 2 is brought in contact with the inside of the wells 26 to 31. Then both trunks 34 and 43 are connected and fixed to each other. Mutually butting bottom plates and lateral bulkheads are welded after displacing water from both trunks.

Reducing method of contact resistance

Abstract: PURPOSE:To reduce contact resistance as well as obtain an ohmic contact, by implanting impurity ions in the vicinity of the contact area between a high- melting metal and Si through the high-melting metal. CONSTITUTION:An SiO2 film 3 is opened on an N-layer 2 of an Si substrate 1, and an Mo film 5 is deposited thereon by the CVD method. After P ions are implanted through the Mo film 5, a heat treatment is applied thereto at about 900 deg.C. Thereby, the resistance between the N-layer 2 and the Mo is remarkably reduced, and there is no possibility that the contact resistance value rises or the contact changes to a nonohmic contact thereafter. Accordingly, heat treatment can be applied even after making the contact. In other words, the thus obtained ohmic contact can advantageously cope with various manufacturing processes of the device.

Contacting method of body in contact printing process

Abstract: PURPOSE:To realize a good state of contact, by making one body curved from the center part against the other body, and subsequently moving one supporting means in the direction crossing the contact face to contact tightly up to the circumferential part. CONSTITUTION:After the position alignment of a mask 1 and a wafer 3 is completed, a feed screw 5 is rotated by a step-motor 6, and an up-and-down moving member 9 is lifted. At the same time, a wafer chuck 4 rises in a state of holding the wafer 3, and the wafer 3 is firmly fixed to a position separated at a prescribed interval from the mask 1. Subsequently, the inside of a vacuum chamber 8 is deaerated through a conduit 7, the mask and the wafer start to contact, and the mask is largely curved and contacts closely from the vicinity of the center. Subsequently, as vacuum pressure is raised, the contact area expands. After that, the screw 5 is rotated by the motor 6, and the wafer 3 held on the chuck 4 through the member 9 is lifted up to a position where the gap quantity against the mask 1 is very small. As a result, bending of the mask is eliminated, and the degree of contact of the circumferential part can be increased.