115 results about "Wall shear" patented technology

The present invention relates to a rotary blood pump with a double pivot contact bearing system with an operating range between about 50 mL/min and about 1500 mL/min is described, wherein the force on the upper bearing is less than 3N during operating speeds up to 6000 rpm. The invention also relates to a method of using a blood pump system for persistently increasing the overall diameter and lumen diameter of peripheral veins and arteries by persistently increasing the speed of blood and the wall shear stress in a peripheral vein or artery for period of time sufficient to result in a persistent increase in the overall diameter and lumen diameter of the vessel is provided. The blood pump system may also be used to reduce venous hypertension in a lower extremity and increasing the rate of healing of lower extremity venous ulcers in patients is provided. The blood pump system includes a blood pump, blood conduit(s), a control system with optional sensors, and a power source. The pump system is configured to connect to the vascular system in a patient and pump blood at a desired rate. The pumping of blood is monitored and adjusted, as necessary, to maintain the desired elevated blood speed and wall shear stress, and the desired pulsatility in the target artery or vein in order to optimize the rate and extent of the persistent increase in the overall diameter and lumen diameter of the target peripheral artery or vein or to result in a reduction in venous blood pressure in the treated lower extremity or healing of the lower extremity venous ulcer.

A system and method for increasing the speed of blood and wall shear stress (WSS) in a peripheral vein for a sufficient period of time to result in a persistent increase in the overall diameter and lumen diameter of the vein is provided. The method includes pumping blood at a desired rate and pulsatility. The pumping is monitored and adjusted, as necessary, to maintain the desired blood speed, WSS and pulsatility in the peripheral vein in order to optimize the rate and extent of dilation of the peripheral vein.

This system is a computer-based system for analyzing a blood flow at a target vascular site of a subject by means of a computer simulation, having a three-dimensional shape extraction unit, by a computer, for reading a captured image at the target vascular site and generating three-dimensional data representing a shape of a lumen of the target vascular site; a fluid dynamics analysis unit, by a computer, for determining state quantities (pressure and flow velocity) of blood flow at each position of the lumen of the target vascular site by means of computation by imposing boundary conditions relating to blood flow to the three-dimensional shape data; a blood flow characteristic determination unit for determining, from the state quantities of the blood flow determined by the fluid dynamics analysis unit, a wall shear stress vector at each position of the lumen wall surface of the target vascular site, determining relative relationship between a direction of the wall shear stress vector at a specific wall surface position and directions of wall shear stress vectors at wall surface positions surrounding the specific wall surface position, and from the morphology thereof, determining characteristics of the blood flow at the specific wall surface position and outputting the same as a determined result; and a display unit, by a computer, for displaying the determined result of the blood flow characteristic which is graphically superposed onto a three-dimensional shape model.

There is disclosed a method of transporting a produced fluid through a pipe while limiting deposits at a desired pipe inner-wall location comprising providing a pipe having an inner surface roughness Ra less than 2.5 micrometers at said desired pipe inner-wall location, forcing the produced fluid through the pipe, wherein the produced fluid has a wall shear stress of at least 1 dyne per centimeter squared at said desired pipe inner-wall location.

The invention relates to a hemodynamic fast planning method for personalized coronary artery bypass graft surgery. According to the method, a personalized coronary artery lumped parameter model is built according to information of a patient, the coronary artery fractional flow reserve for reflecting coronary artery functional diseases is calculated, the surgery indication is evaluated, and in combination with SYNTAX grading of anatomic disease extension, the evaluation is used as the comprehensive evaluation basis for selecting a coronary artery bypass graft surgery strategy. A bypass graft scheme is selected on the premise of adaptation and involves the bypass graft blood vessel number, the bypass graft position, the transfer catheter type and the like. The personalized lumped parameter model is calculated, and postoperative coronary artery flow and pressure changes and postoperative bypass graft blood vessel parameters are obtained. According to the average wall shear stress, the wall shear stress oscillation index and the competitive flow degree, the long-term permeability of the transfer catheter of the scheme is analyzed. The long-term permeability of transfer catheters in different bypass graft schemes is compared, and the best bypass graft scheme is obtained. The hemodynamic fast planning method solves the problems that an existing method is invasive, indirect, long in consumed time and the like.

The invention discloses a device and a method for testing wall shear stress based on flexible heat-sensitive sensors. The device comprises a flexible heat-sensitive sensor array, a high-precision constant-current source, a signal conditioning circuit, a data acquisition module, a temperature compensation module, a data transmission module and a data processing and storage module. The device and the method have the intentional effects that the device adopts the flexible heat-sensitive sensors which are low in thickness, so that a flow field to be tested is hardly affected, and the accuracy and validity of testing are improved; the flexible heat-sensitive sensors are based on heat transfer theory and are fixed in the flow field by adopting an attaching method, so that the wall shear stress can be subjected to non-destructive real-time measurement, the change of underwater wall shear stress can be sensed effectively, impact of a wider range caused by water flow and impurities in water can be withstood, and the test on the underwater wall shear stress can be realized; and due to the adoption of the flexible heat-sensitive sensors, the flexible heat-sensitive sensors can be attached tightly according to the shape of a tested wall, so that the environmental adaptability of the device is improved.

A system for hemodynamic simulation comprises a vessel having properties of a blood vessel, a reservoir containing a quantity of fluid, tubing connecting the vessel and reservoir, and at least one pump for circulating the fluid within the system. Fluid can be tissue culture medium or blood analog fluid, and the vessel may include mammalian cells attached to its inside. A drive system, comprising two reciprocating drive shafts that are coupled by a cam, enables the uncoupling of pulsatile flow and pulsatile pressure to provide independent control over wall shear stress and circumferential strain. The shaft drives two pumps that are 180 degrees out-of-phase and are connected upstream and downstream of the vessel, and effect this uncoupling.

A non-toxic anti-fouling coating paste having a rheologic switching behavior based on a flow point, which can be set to the hydrodynamic and biological environmental conditions of a submarine component to be protected and which is between 5 Pa and 2,000 Pa above the wall shearing stress of the unfouled component to form a substrate which prevents colonization by marine fouling organisms.

The invention discloses a micro capacitance-type wall shear stress sensor and a manufacturing method of the micro capacitance-type wall shear stress sensor based on through silicon via (TSV) technology, and belongs to the technical field of sensors. The micro capacitance-type wall shear stress sensor comprises a floating unit anchor point 1, an elastic beam 2, a movable broach 3, a fixed broach 4, a fixed broach anchor point 5, a TSV lead 6, a floating unit 7, a sacrificial layer 8, a substrate layer 9 and a TSV electric insulation layer 10, and is manufactured through a micro machining process and a metal plating process. According to the micro capacitance-type wall shear stress sensor based on the TSV technology, the original lead bonding process is replaced by a back-surface lead process, so that the metal leas is prevented from being exposed in a flow filed to generate interference. The packaging size of the sensor is reduced, arraying of the sensor is benefited, and three-dimensional (3D) packaging of the sensor and an integrated circuit is benefited. A measurement device does not invade in the flow field, so that no-invasion-type wall shear stress measurement can be carried out on the flow field.

A system and method for increasing the speed of blood and the wall shear stress in a peripheral artery or peripheral vein to a sufficient level and for a sufficient period of time to result in a persistent increase in the overall diameter and lumen diameter of the artery or vein is provided. The method includes systems and methods to effect the movement of blood at the desired rate and in the desired direction. The movement of blood is monitored and adjusted, as necessary, to maintain the desired blood speed and wall shear stress in the peripheral artery or vein in order to optimize the rate and extent of persistent diameter increase of the peripheral artery or peripheral vein.

The invention relates to light-weight recyclable and high-efficiency construction building equipment and a construction method thereof. The building equipment comprises hanging seats, sleeve frames, hydraulic cylinders, upper reversing boxes, lower reversing boxes and track upright posts, wherein a plurality of hanging seats are fixed on the outer side of an outer wall shear wall, the sleeve frames and the track upright posts are clamped on the hanging seats, the sleeve frames are clamped on the outer sides of the track upright posts, the lower reversing boxes are fixed at the upper ends of the sleeve frames, the hydraulic cylinders are connected with the upper reversing boxes and the lower reversing boxes, the side surfaces of the track upright posts are provided with window lattice holeswhich are matched with the upper reversing boxes and the lower reversing boxes for climbing, the upper ends of the track upright posts are fixedly connected with a top platform, and the top platformis provided with a hanging frame and a form through a hanging rod in a suspending mode. The equipment can improve the construction work efficiency of a high-rise residential building, and is a light-weight, recyclable and high-efficiency construction equipment integrated platform device, the recyclable performance is strong, and the overall construction period is saved.

The invention discloses a measurement method of a transition position of airfoil surface boundary layer based on a distributed thermosensitive optical fiber. The method comprises the steps of laying a temperature optical fiber on the surface of an airfoil model, and measuring the temperature distribution of airflow flowing through the surface of an object through a distributed thermosensitive optical fiber to judge a flow transition position. Back Rayleigh scattering light in the optical fiber is measured through a backlight reflexometer, and after loss and optical fiber length information are obtained and a sensing module is added, a common monomode optical fiber serving as a sensor can be used to perform temperature low-frequency testing reaching 1cm space resolution and 0.1-DEG C temperature resolution within a 70m range. Compared with other transition measurement technology, both the temperature resolution and the special accuracy judged by transition position are enhanced. The method has the advantages that a dynamic pressure sensor is not required to be embedded on the surface of an object for judging transition through dynamic pressure, the method is easier to realize than wall shear stress measurement and transition measurement judgment method through a thermal infrared imager, and the spatial resolution is high.

The present invention relates to a numerical simulation method for the occurrence of rainfall in the aircraft flight. The method comprises: generating an aircraft flow field space calculation grid; determining flight conditions and rainfall conditions; solving air phase fluid aerodynamic performance data and air phase fluid wall shear stress; solving the local raindrop collection rate and the local raindrop impact mass flow on the surface of the aircraft; solving the increment of the raindrop impact coefficient; taking body-fitted grids on the airfoil surface in the aircraft flow field space calculation grid as surface water film control bodies, setting the air flow attach point, the air flow transition point and the air flow reattach point that are presented on the airfoil surface, and solving the water film thickness of all the surface water film control bodies successively; solving four parameters of the raindrop sputtering model; solving the equivalent water film surface roughness; updating the geometrical shape of the aircraft according to the water film thickness, and reconstructing the aircraft flow field space calculation grid; obtaining updated air phase fluid aerodynamic performance data; and obtaining the aerodynamic performance loss data of the aircraft caused by the rainfall.

The invention discloses a bulk acoustic wave wall shear stress sensor comprising a base, a supporting layer, detection elements, sensitive elements, a shell, an upper cover plate and a read-out circuit. The base is arranged below the supporting layer. A cavity structure is formed between the supporting layer, the shell and the upper cover plate. The detection elements arranged in the cavity are installed on the supporting layer. The sensitive elements are installed on the detection elements. The top surface of the sensitive elements is level with the top surface of the upper cover plate, and a gap is reserved between the top surface of the sensitive elements and the opening of the upper cover plate. The read-out circuit is connected with the detection elements through the welding disc of the bottom part of the base. Surface frictional resistance can be converted into stress load of a FBAR so that resonant frequency of the FBAR is changed, and read-out or measurement of the detection signal of the bulk acoustic wave wall shear stress sensor is realized through the read-out circuit. The bulk acoustic wave wall shear stress sensor has the characteristics of being small in size, high in sensitivity, high in integration and conformal with a measured object and can meet the application requirements for frictional resistance sensors in the field of aerospace, weapon engineering and automobiles.

The invention relates to an anti-seismic energy-saving heat preservation brick, which comprises a brick body. The upper end surface of the brick body is provided with a longitudinal tenon, and the corresponding position of the above-mentioned longitudinal tenon on the lower end surface of the brick body is provided with a longitudinal groove that can be fitted with the above-mentioned tenon. , one end face of the brick body is provided with a lateral tenon, and the corresponding position of the above-mentioned lateral tenon on the other side of the brick body is provided with a lateral groove that can be fitted with the above-mentioned lateral tenon. There are two or more rows of longitudinal holes, each of which is filled with light-weight thermal insulation material. When using the embodiment of the present invention to build walls, it can be carried out layer by layer. The lateral tenons of each brick are respectively embedded in the lateral grooves of adjacent bricks. The bottom groove of each brick is in line with the top tenon of the lower brick. Chimeric. Each brick is tightly mate with adjacent bricks. The shear bearing capacity of the wall is good, the part of the tenon is not easily damaged, and the seismic performance is good. At the same time, there are light-weight thermal insulation materials in the brick body, and the thermal insulation performance of the wall is good. The invention is both energy-saving and shock-resistant.

The invention discloses a method for constructing a full-biological tissue engineering blood vessel. The method is characterized in that an acellular tissue matrix is prepared from a sheep carotid artery; endothelial progenitor cells, smooth muscle progenitor cells and adipose-derived stem cells are respectively used as seed cells for constructing tunica intima vasorum, tunica media vasorum and tunica externa; and dynamic processes of wall shear stress, annular tension and axial tensile stress during construction of the blood vessel are realized by a bioreactor. The optimized acellular tissue matrix and optimized seed cell sources are adopted, and standard 3-D (three-dimensional) stress and dynamic regulation are realized in a construction process, so that the structure, mechanical characteristics and biological activities of the constructed tissue engineering blood vessel are close to those of a natural blood vessel. Accordingly, the method has industrial production and clinical application prospects, and a foundation is laid for the tissue engineering blood vessel to access markets.

The invention discloses a micro piezoresistive device capable of carrying out non-destructive measurement on wall shear stress of a flow field and a manufacturing method thereof, belonging to the technical field of sensors. The device comprises a sensing part 1, an elastic deformation part 2, a base 6, as well as a piezoresistor, a wire and a pad which are arranged on the elastic deformation part 2; wherein the device is arranged and fixed on a structure 7 to be measured by virtue of the base 6, and the upper surface of the sensing part 1 flushes with the surface to be measured of the structure 7 to be measured. The micro piezoresistive device for measuring wall shear stress provided by the invention can achieve better comprehensive performances: (1) high sensitivity is realized, and the bending stiffness of the elastic deformation part 2 can be greatly reduced so that the device achieves higher measuring sensitivity; (2) manufacturing steps and process are simple; only a conventional micro-processing process is required, the manufacturing cost is reduced, and the reliability and controllability of the process are improved; and (3) non-intrusive wall shear stress measurement can be carried out on the flow field.

Microelectromechanical systems (MEMS)-based devices capable of measuring wall shear stress vectors in three-dimensional aerodynamic flow fields are provided. A device can include a sensor that senses wall shear stress vectors in two in-plane axes and an interface circuit including a modulation section and a demodulation section. The device can be capable of making direct, real-time wall shear stress measurements without any need for using secondary measurements and/or models for validation.

A system for hemodynamic simulation comprises a vessel having properties of a blood vessel, a reservoir containing a quantity of fluid, tubing connecting the vessel and reservoir, and at least one pump for circulating the fluid within the system. Fluid can be tissue culture medium or blood analog fluid, and the vessel may include mammalian cells attached to its inside. A drive system, comprising two reciprocating drive shafts that are coupled by a cam, enables the uncoupling of pulsatile flow and pulsatile pressure to provide independent control over wall shear stress and circumferential strain. The shaft drives two pumps that are 180 degrees out-of-phase and are connected upstream and downstream of the vessel, and effect this uncoupling.

The invention discloses a full analytical model construction method of a capacitance type wall shear stress sensor probe. The capacitance type wall shear stress sensor probe comprises elastic beams (1), a floating unit (2), a base (3), movable comb teeth (4), fixed comb teeth (5), limiting structures (6) and an insulating substrate (7). The model construction method includes the following steps that: shear stress is applied onto the capacitance type wall shear stress sensor probe; and full analytical model construction is performed for the range, inherent frequency, resolution and non-linearity of the capacitance type wall shear stress sensor probe. According to the full analytical model construction method of the capacitance type wall shear stress sensor probe of the invention, the full analytical model of the capacitance type wall shear stress sensor probe is constructed, so that relationships between sensor probe structural parameters and sensor performance indexes can be defined, and therefore, a designer can determine appropriate structural parameters according to the requirements of a user for sensor performance and can obtain a sensor design optimal program in a more targeted manner.

The invention discloses a design method of a micro texture having a flat wall surface drag reduction function, and belongs to the field of surface texture design. According to the gas flow rate, an area, namely a buffer layer between a viscous bottom layer and a logarithmic law layer, where the wall shear stress is generated is determined by combining a boundary layer theory. Dimensionless treatment is performed on the size, and the thickness of the buffer layer is calculated so as to determine the height range of the micro texture. According to a Reynolds formula, the critical point of the fluid flowing from the laminar flow to the turbulent flow is calculated, and the arrangement area range of the micro texture is obtained. According to the two data, resistance reduction micro texture design is carried out, CREO software modeling is utilized, simulation is carried out through flow field simulation software FLUENT, the micro texture resistance reduction situation is analyzed, characteristic parameters of the micro texture are optimized, and the design of the flat-wall resistance reduction micro texture with the resistance reduction effect is achieved. The boundary layer theory isadopted, micro texture parameter design is conducted through layering and positioning of the turbulence area, the size design range of the drag reduction micro texture can be effectively narrowed, thesimulation amount is reduced, and the resource cost is saved.