2242 results about "Shear stress" patented technology

One or more rigid components associated with an articulating bone are used to encase, encapsulate, contain, or otherwise protect a compressible / resilient member. The embodiments are applicable not only to artificial disc replacement (ADR) devices, but also to joint situations including total knee and hip arthroplasty. The cushion elements in the preferred embodiments include synthetic rubbers, hydrogels, elastomers, and other polymeric materials such as viscoelastic polymers and foam polyurethanes. The invention effectively combines the advantages of such materials (cushioning, shape memory, and expansion after insertion in the case of hydrogels), while providing increased protection, particularly the elimination of shear stresses. When applied to an ADR, the invention also minimizes the risk of extrusion.

A method and soft tissue cleat device for improving the repair of soft tissue damage. A disc having projections pierces soft tissue and securely joins with a second disc to coapt the interposed soft tissue. This provides an increased pull-out strength of the suture and resistance to shear stresses, improving the quality of the repair. The present invention may be used with any bone fixation devices to reattach soft tissue to bone, and may also be used to rejoin soft tissues after a tear in the tissue.

Methods of medical treatment and diagnosis using mediators released by endothelial cells stimulated by external addition of pulses to the circulation are disclosed. The external pulses produce circumferential shear stress in body fluid channels that subsequently stimulates the endothelial cells to produce mediators that become available for therapeutic and diagnostic purposes. The preferred means of adding external pulses is the mechanical inducement of periodic acceleration of the body or parts of the body by a reciprocating motion platform.

Methods of medical treatment and diagnosis using mediators released by endothelial cells stimulated by external addition of pulses to the circulation are disclosed. The external pulses produce circumferential shear stress in body fluid channels that subsequently stimulates the endothelial cells to produce mediators that become available for therapeutic and diagnostic purposes. The preferred means of adding external pulses is the mechanical inducement of periodic acceleration of the body or parts of the body by a reciprocating motion platform.

One or more rigid components associated with an articulating bone are used to encase, encapsulate, contain, or otherwise protect a compressible / resilient member. The embodiments are applicable not only to artificial disc replacement (ADR) devices, but also to joint situations including total knee and hip arthroplasty. The cushion elements in the preferred embodiments include synthetic rubbers, hydrogels, elastomers, and other polymeric materials such as viscoelastic polymers and foam polyurethanes. The invention effectively combines the advantages of such materials (cushioning, shape memory, and expansion after insertion in the case of hydrogels), while providing increased protection, particularly the elimination of shear stresses. When applied to an ADR, the invention also minimizes the risk of extrusion.

A multimodal polymer composition for fiber optical cables and a fiber optical cable comprising the composition are disclosed. The composition is characterized in that it comprises a multimodal polyethylene with a density of 0.920-0.965 g / cm3 and a viscosity at a shear stress of 2.7 kPa (eta2.7kPa) of at least 150 kPa.s, said multimodal polyethylene comprising a low molecular weight (LMW) ethylene homo- or copolymer fraction and a high molecular weight (HMW) ethylene copolymer fraction, said multimodal polymer composition having a weight ratio of the LMW fraction to the HMW fraction of (35-55):(65-45). Preferably, the multimodal polyethylene is a bimodal polyethylene and has a shear thinning index (SHI), defined as the ratio of the viscosities at shear stresses of 2.7 and 210 kPa, respectively, of SHI2.7 / 210=20-150. Also, preferably, the multimodal polyethylene has a MFR5 of 0.1-2.0 g / 10 min and a melt strength at 190° C. of at least 4 g. The multimodal polymer composition is particularly useful as a material for slotted core elements of fiber optical cables of the slotted core type.

A nonaqueous electrolyte secondary battery includes a negative electrode including a negative electrode current collector and a negative electrode active material layer that is formed on a first region of the negative electrode current collector, a negative electrode terminal connected to an edge section of a second region of the negative electrode current collector, a positive electrode including a positive electrode active material layer positioned to face the negative electrode active material layer and the second region, and a stress imparting member which imparts a tensile stress or a shearing stress to the second region.

A microfluidic platform for single-cell capture, stimulation, and imaging. It passively traps 4,000 single cells on a 4.5 mm2 footprint in 30 seconds, with a single-cell loading efficiency of 95%. The array format and optimized geometry allows for easy, robust and efficient single-cell loading, while maintaining captured cells in a low shear stress environment for long-term studies. Because cells are captured sequentially, the system is adequate for rare cell samples. Trapped cells can be exposed to various environmental conditions and chemical stimulus and their dynamic response can be monitored over time. The information gained from high-throughput, single-cell time lapsed imaging presents new opportunities in quantifying cellular responses, as averaged information by other measurement methods eliminates sub-population phenotypes.

The invention provides devices that can be used to deliver a therapeutic agent to a treatment site within the vessel of a patient at increased pressure, while limiting the contact with and pressure placed on the vessel walls. Devices according to the invention include an expandable structure arranged around and on a tube having a lumen. The expandable structure may include a sealing ring that makes contact with the interior surface of a vessel to prevent or decrease fluid flow during delivery of a therapeutic agent. This allows delivery of a therapeutic agent with decreased risk of injury to the treatment site. The invention also provides for large lumen diameters, preventing shearing stress on therapeutic agents such as cell slurries.

According to embodiments of the present invention, a distributed pressure and shear stress sensor includes a flexible substrate, such as PDMS, with a waveguide formed thereon. Along the waveguide path are several Bragg gratings. Each Bragg grating has a characteristic Bragg wavelength that shifts in response to an applied load due to elongation / compression of the grating. The wavelength shifts are monitored using a single input and a single output for the waveguide to determine the amount of applied pressure on the gratings. To measure shear stress, two flexible substrates with the waveguide and Bragg gratings are placed on top of each other such that the waveguides and gratings are perpendicular to each other. To fabricate the distributive pressure and shear sensor, a unique micro-molding technique is used wherein gratings are stamped into PDMS, for example.

A method and apparatus is disclosed for providing shear-induced alignment of nanostructures, such as spherical nanodomains, self-assembled nanodomains, and particles, in thin films, such as block copolymer (BCP) thin films. A silicon substrate is provided, and a thin film is formed on the substrate. A pad is then applied to the thin film, and optionally, a weight can be positioned on the pad. Optionally, a thin fluid layer can be formed between the pad and the thin film to transmit shear stress to the thin film. The thin film is annealed and the pad slid in a lateral direction with respect to the substrate to impart a shear stress to the thin film during annealing. The shear stress aligns the nanostructures in the thin film. After annealing and application of the shear stress, the pad is removed, and the nanostructures are uniformly aligned.

According to embodiments of the present invention, a distributed pressure and shear stress sensor includes a flexible substrate, such as PDMS, with a waveguide formed thereon. Along the waveguide path are several Bragg gratings. Each Bragg grating has a characteristic Bragg wavelength that shifts in response to an applied load due to elongation / compression of the grating. The wavelength shifts are monitored using a single input and a single output for the waveguide to determine the amount of applied pressure on the gratings. To measure shear stress, two flexible substrates with the waveguide and Bragg gratings are placed on top of each other such that the waveguides and gratings are perpendicular to each other. To fabricate the distributive pressure and shear sensor, a unique micro-molding technique is used wherein gratings are stamped into PDMS, for example.

A method for computing patient specific blood viscosity and patient specific shear stress on a location of interest in the interior of a blood vessel that includes calculating shear rate of blood in the vessel, using imaging techniques and calculating the shear rate related blood viscosity.

Arthroplasty devices having improved bone in growth to provide a more secure connection within the body. Different embodiments disclosed include devices having threaded intramedullary components, devices configured to receive bone growth promoting substances, devices with resorbable components, and devices configured to reduce shear stress.

A method of forming a multilayer film is disclosed, comprising coextruding a first layer comprising a weatherable composition, and a second layer comprising a polycarbonate composition comprising a visual effect filler, wherein the first and second layers are formed by flowing each of the weatherable composition and polycarbonate composition through separate flow channels in a multi-manifold coextrusion die. The shear stress during extrusion on the polycarbonate composition is greater than or equal to 40 kilo-Pascals.

Arthroplasty devices having improved bone in growth to provide a more secure connection within the body. Different embodiments disclosed include devices having threaded intramedullary components, devices configured to receive bone growth promoting substances, devices with resorbable components, and devices configured to reduce shear stress.

A winch assembly is disclosed that eliminates rope crushing, even when synthetic ropes are used. Tension is applied to the rope by at least one traction sheave so that the tension at the drum is reduced. By using multiple sheaves with large wrap angles traction can be applied to the rope over a much larger area, reducing shear stress and minimizing internal wear due to relative motion of rope components. The winch drum and at least one traction sheave are driven independently, preferably by AC induction motors using frequency control. The winch assembly may operate in conjunction with a hydraulic tensioner so that lower horsepower motors can be used to maintain constant tension in moving systems.

Arthroplasty devices having improved bone in growth to provide a more secure connection within the body. Different embodiments disclosed include devices having threaded intramedullary components, devices configured to receive bone growth promoting substances, devices with resorbable components, and devices configured to reduce shear stress.

Multi-phase personal care compositions comprising: (a) at least one personal care composition phase; and (b) at least one another personal care composition phase; wherein the phase (a) and said the phase (b) are visually distinct phases that are packaged in physical contact, wherein the phase (a) and the phase (b) have a yield stress of from about 1 Pa to about 100 Pa, and wherein the viscosity ratio of the phase (a) to the phase (b) is from about 1:15 to about 15:1 at shear stress over the yield stress of the phases (a) and (b) up to at least 200 Pa. By matching rheology profiles of each phase compositions in such kinetic conditions, desired patterns of multi-phase personal care compositions are easily obtained and / or maintained for a longer period of time.

When a substrate layer (desired semiconductor crystal) made of a group III nitride compound is grown on a base substrate comprising a lot of projection parts, a cavity in which a semiconductor crystal is not deposited may be formed between each projection part although it depends on conditions such as the size of each projection part, arranging interval between each projection part and crystal growth. So when the thickness of the substrate layer is sufficiently larger compared with the height of the projection part, inner stress or outer stress become easier to act intensively to the projection part. As a result, such stress especially functions as shearing stress toward the projection part. When the shearing stress becomes larger, the projection part is ruptured. So utilizing the shearing stress enables to separate the base substrate and the substrate layer easily. The larger the cavities are formed, the more stress tends to concentrate to the projection parts, to thereby enable to separate the base substrate and the substrate layer more securely.

A process and an apparatus for producing metallic glass which are capable of producing a bulk amorphous alloy of desired shape, in particular, a bulk amorphous alloy of desired final shape are provided. In the present invention, the molten metal at a temperature above the melting point is selectively cooled at a rate higher than the critical cooling rate, and the product comprises single amorphous phase which is free from the crystalline phase formed by the development of crystal nuclei through nonuniform nucleation. The present invention is capable of producing the bulk amorphous alloy which is free from casting defects such as cold shuts and which has excellent strength properties in a simple process at a high reproducibility. Accordingly, a bulk metallic glass of desired shape is produced by filling a metal material in a hearth; melting the metal material by using a high-energy heat source which is capable of melting the metal material; pressing the molten metal at a temperature above the melting point of the metal material to deform the molten metal into the desired shape by at least one of compressive stress and shear stress at a temperature above the melting point, while avoiding the surfaces of the molten metal cooled to a temperature below the melting point of the metal material from meeting with each other during the pressing; and cooling the molten metal at a cooling rate higher than the critical cooling rate of the metal material simultaneously with or after the deformation to produce the bulk metallic glass of desired form.

This invention provides a method apparatus for electrically connecting a semiconductor die, such as a power MOSFET, to a substrate on which the die is mounted, e.g., a lead frame, with a conductive strap, such that the connection is resistant to the shear stresses incident upon it with changes in temperature of the device. The method includes providing a conductive strap, and in one embodiment thereof, forming a recess in the top surface of the substrate. The bottom surface of a flange portion of the strap is attached to the floor of the recess such that the recess captures the flange and prevents relative horizontal movement of the flange and substrate with variations in the temperature of the device.Other embodiments include attaching the strap to the die and substrate with joints of a resilient conductive elastomer, and forming apertures in the strap and substrate that cooperate with a conductive joint material to reinforce the connection against temperature-induced shear forces.

The invention provides a method for forming polymer microrods, the method including the steps of providing a polymer solution comprising a polymer dissolved in a first solvent; providing a dispersion medium comprising a second solvent, wherein the first solvent and the second solvent are miscible or partially soluble in each other, and wherein the polymer is insoluble in the second solvent; adding the polymer solution to the dispersion medium to form a dispersed phase of polymer solution droplets within the dispersion medium; and introducing a shear stress to the dispersion medium and dispersed polymer solution droplets for a time and at a shear rate sufficient to elongate the polymer solution droplets to form microrods and solidify the microrods by attrition of the polymer solvent into the dispersion medium.

A device, system and method is disclosed in which small volume blood samples are subjected to shear forces and shear stresses between two parallel planar surfaces to which linear motion trajectories are imparted. The formation of clots or coagulation of the sample is measured from dynamic mechanical coupling which occurs between the two parallel planar surfaces. Detection of the coagulation response can be achieved through optical probing or by measurement of physical effects of the blood sample binding to the planar surfaces, and restricting movement thereof.

A stack of piezoelectric elements, in the form of an elongated rod divided in to segments, for generating electric energy in response to compressive stress is provided comprising: piezoelectric elements stacked one on top of the other such that electrodes of same polarity of adjacent disks are touching A holding structure, such as a screw holds the piezoelectric elements together between a top and a bottom end pieces which transfer mechanical compressive stress to the elements in the stack. The holding structure accepts shear stresses, provides preloading stress on the stack and prevents buckling of the stack under pressure. A recess in the end piece, deeper than the head of the screw, ensures that load placed on the stack will compress the piezoelectric elements and not on the screw.

Improved methods and apparatuses for directly monitoring well casing strain and structural integrity are disclosed that allows for monitoring of potentially damaging strain from any orientation or mode and over long stretches of well casing. In a preferred embodiment, optical fiber sensors are housed within a housing and attached to the exterior surface of the casing. The sensors may be aligned parallel, perpendicular, or at an appropriate angle to the axis of the casing to detect axial, hoop, and shear stresses respectively. The sensors are preferably interferometrically interrogatable and are capable of measuring both static and dynamic strains such as those emitted from microfractures in the well casing. Analysis of microfracture-induced acoustics includes techniques for assessment of relatively high frequencies indicative of the presence of microfractures. Assessment of the timing of the arrival of such acoustics at various sensors deployed along the casing further allows for the location of strain to be pinpointed.