276 results about "Variable pressure" patented technology

The invention provides a variable rotating speed-variable displacement differential pressure controllable valve front compensation load sensitive system. The variable rotating speed-variable displacement differential pressure controllable valve front compensation load sensitive system comprises a control unit, a driving motor assembly, a variable differential pressure load sensitive pump assembly, a variable differential pressure load sensitive valve assembly, a pilot hydraulic control unit, a pilot handle assembly, an actuator assembly, a sensor assembly and a motor rotating speed control module. The driving motor assembly drives the variable pressure difference load sensitive pump assembly to supply oil to the variable pressure difference load sensitive valve assembly, and then the actuator assembly is driven to operate. The pilot hydraulic control unit provides set pressure; the pilot handle assembly outputs a signal to the variable pressure difference load sensitive valve assembly; the sensor assembly detects the maximum load pressure of the system and the outlet pressure of the variable pressure difference load sensitive pump assembly; the control unit controls the target rotating speed of the driving motor assembly and the control pressure of the pilot hydraulic control unit. Compared with an existing upstream compensation load sensitive system, the problem of speed imbalance of an actuator under the flow saturation working condition is effectively avoided, and the control performance is remarkably improved.

The utility model relates to a monitoring variable-pressure coffee machine, which aims at solving the technical problems that the existing similar products are difficult to realize the setting and adjustment of extraction pressure gears through program or motor control, and a variable-pressure valve group module assembly needs to be improved. The coffee machine is characterized in that a stepping motor is arranged at the top of a main body support above a variable pressure valve group module of the coffee machine, a transmission shaft at the stepping motor extending into the main body support is connected with the extending end of a piston ejector rod of the variable pressure valve group module through an ejector rod connecting shaft, and the ejector rod connecting shaft is a coupler; the inner wall conical surface at the position of a cavity limiting platform in a cavity main body of the pressure transformation valve group module corresponds to and is aligned with the outer diameter conical surface at the position of an ejector rod limiting platform of a piston ejector rod in the pressure transformation valve group module, a water outlet is formed in one side above the cavity limiting platform in the cavity main body, and a compression spring is arranged on the outer diameter of the piston ejector rod in the cavity main body; the piston ejector rod is driven by the ejector rod connecting shaft and the stepping motor to move up and down, and the distance between the ejector rod limiting platform and the cavity limiting platform is adjusted.

The invention belongs to the technical field of powder metallurgy, and discloses a titanium hydride production system and a preparation method.The production system comprises a transverse reaction bin provided with a hopper, a conveying mechanism, a material taking unit, a hydrogen injection variable pressure unit, a reaction unit and a cooling unit, and the material taking unit, the hydrogen injection variable pressure unit, the reaction unit and the cooling unit are sequentially connected and are connected end to end through the conveying mechanism; the transverse reaction bin is sequentially conveyed among the units through the conveying mechanism, more than two parallel sliding rails are fixedly arranged on the inner side wall of the bin body, the transverse reaction bin can be circularly conveyed in a production system through the end-to-end functional unit structures, different preparation processes are carried out on the reaction bins of different units within the same time, and the productivity is remarkably improved. According to the titanium hydride production system, high-yield titanium hydride preparation is achieved, the yield is increased by 20 times, and the titanium hydride production system is energy-saving and efficient. The method is suitable for industrial mass production of titanium hydride.

The invention discloses an air separation pressure swing intelligent adsorption pollution discharge method, system and device combined with a pressure curve, and relates to the technical field of intelligent pollution discharge. The air separation pressure swing intelligent adsorption pollution discharge method, system and device combined with the pressure curve comprises the following steps: S1, collecting running state data in real time, and preprocessing the running state data; s2, performing pressure disturbance intensity analysis on the operation state data; s3, performing real-time analysis and feature extraction on the pressure curve; s4, performing start-stop risk prediction on the operation state data; and S5, integrating the operation state data, the pressure disturbance intensity analysis result and the start-stop risk prediction result to execute a pollution discharge control instruction. The problems that an air compressor and a pressure swing adsorption system lack linkage control based on pressure change, pollution discharge easily causes pressure fluctuation and frequent starting and stopping, energy consumption is increased, equipment abrasion is caused, and an existing control mode lacks a feedforward adjusting mechanism are solved.

The invention provides a gastrointestinal fluid decompression device for gastrointestinal surgery, and belongs to the field of medical instruments. Comprising a detachable gas-liquid collecting mechanism and a variable pressure control mechanism. By means of the deformation phenomenon generated when the elastic gas film is subjected to the action of gas, the buffering effect can be generated on flowing gas pressure, the surgical risk rate caused by the too large instantaneous value of the gas pressure can be effectively reduced through buffering, meanwhile, once the negative pressure value is overloaded, the elastic gas film can completely close the hole diameter under the action of the external atmospheric pressure, and the surgical risk rate is reduced. Therefore, an air flow path is blocked, and more serious operation accidents caused by air pressure negative value overload are prevented.

Devices and methods are provided for cleaning and / or drying devices, such as drinking straws for beverage containers, medical devices, endoscopic instruments, etc. A drying device for use with an endoscopic instrument includes an elongate member configured for advancement through an internal lumen within the endoscopic instrument, and a drying member removably coupled to a portion of the elongate member. The drying element includes a variable pressure region shaped and configured to increase hydrodynamic fluid friction and fluid pressure applied to the wall of the interior lumen of the endoscope to more effectively remove all moisture and fluid from the interior surface of the endoscopic instrument.

The invention relates to a gear machining process, in particular to a design method for the output length of a variable-pressure-angle hob, and mainly solves the technical problem that the output length of the hob cannot be accurately controlled in an existing method. The method comprises the following steps that 1, according to the generating machining principle, the circumferential length needed by a variable pressure angle hob for hobbing a complete tooth width of a to-be-machined gear is calculated; (2) based on the circumferential length obtained in the step (1), in combination with the helix angle of the variable-pressure-angle hob and the helix angle of the gear to be machined, the axial length of the variable-pressure-angle hob for hobbing a complete tooth width is obtained through calculation; and (3) according to the axial length obtained through calculation in the step (2), in combination with the axial feed amount during hobbing, the cutter output length of the variable-pressure-angle hobbing cutter during hobbing is obtained through calculation. On the basis of the method, the cutter output length of the variable-pressure-angle hob can be accurately controlled, the risk of machining interference of the variable-pressure-angle hob is fundamentally avoided, and then high-precision machining of the gear is achieved.

A device for applying pressure to a physiological pressure point such as the Hegu pressure point, has opposing spring biased jaws in a pivoting relationship. A variable pressure actuator moves a first jaw toward a second jaw and retracts the first jaw from the second jaw. In an application, the second jaw contacts a palm of a hand of a user, and the first jaw contacts an opposite side of the hand of the user, and the jaws cooperate to apply pressure at a physiological pressure point of the hand.

A portable submersible livestock water quality dispensing device and design for a livestock drinking station is provided. The portable submersible livestock water quality dispensing device has a heating element and a variable pressure pump with internal compartments or inserts for accommodating biocides, minerals, vitamins and medicaments and preferably a rotatable circulation device and method for their controlled release and dosing.

The utility model discloses a shock absorber magnetorheological fluid high pressure variable pressure and flow injection mechanism which comprises a mechanism body, a buffer cylinder and a quantitative cylinder are installed on the side of the upper end of the mechanism body, a servo motor is installed in the middle of the upper end of the mechanism body in a positioning mode, and a sliding rail is installed at the front end of the lower portion of the mechanism body. According to the magnetorheological fluid high-pressure variable pressure and flow injection mechanism of the shock absorber, after the liquid injection pump set supplies liquid into the buffer cylinder, a pipeline is sealed through the one-way valve to prevent the liquid from flowing back until the buffer cylinder is full, and the two-way pneumatic control ball valve on the top of the buffer cylinder is opened; the servo mechanism pulls a piston rod in the liquid injection quantitative cylinder to fully travel to synchronously fully fill a cavity in the quantitative cylinder, excess air is exhausted through an exhaust valve at an oil inlet and an oil outlet of the quantitative cylinder, and the pressure required for liquid injection in a pipeline is finely adjusted and kept through a servo motor; and then the servo motor drives the quantitative cylinder to inject the magnetorheological fluid with the required volume into the product according to the set oil injection amount.

An extrudate cooling tank having cooling water chambers adapted for running passage of extrudate serially therethrough at a preselected regulated variable pressures with water in the chambers being at different temperatures, and a wheel-servo motor combination hingedly connected to the chamber and being movable with respect thereto between a first position with the wheel engaging running extrudate and a second position with the wheel remote from engagement with the extrudate.

The invention relates to the technical field of fluid machinery intelligent control, and discloses a centrifugal circulating pump non-differential pressure sensor variable pressure control method based on edge intelligence. Water pump rotating speed and power signals are collected, subjected to normalization processing and then input to a lightweight recurrent neural network (RNN) model deployed at an edge device end; the RNN model serves as a soft sensor, and the flow and the lift value of the most unfavorable point of the pipe network are deduced in real time; and the system dynamically calculates the target lift based on a pipe network characteristic curve according to the reasoned flow, the target lift serves as a set value and forms a closed-loop control loop with the actual lift fed back by the RNN, the rotating speed adjustment amount is output to the frequency converter through a PID algorithm, and finally accurate variable pressure control without the physical differential pressure sensor is achieved. According to the method, the dependence on a tail end physical sensor is eliminated, the cost and the complexity are reduced, meanwhile, the real-time control and the data security of ultra-low delay are realized by utilizing edge calculation, and the response speed, the control precision and the energy-saving effect of the system are effectively improved.

A mechanical swing brake variable control system for an earth-moving machine including an upper revolving car body with swing components mounted on the upper revolving car body, a lower traveling car body with traction components mounted on the lower traveling car body, and a mechanical service brake interconnected with the upper and lower car bodies, controls relative rotation between the upper and lower car bodies. A pressure control device controls a variable pressure applied to the mechanical service brake to vary an amount of swing drive holding torque. An electronic controller monitors and processes signals received from sensors associated with the swing components and machine operator commands, and variably controls the amount of holding torque exerted on the upper revolving car body using the mechanical service brake as a function of one or more of machine roll angle, operational configuration of the swing components, inertial mass of the swing components, and machine operator commands.

The present invention relates to a device for direct injection of a gaseous fuel, in particular hydrogen, which device comprises: a pressure-control unit which is designed to convert a supplied variable pressure level of the gaseous fuel into a fixed constant output pressure level; a distributor unit which is connected to at least one injector for direct injection of the gaseous fuel, which has been guided through the pressure-control unit, into a combustion chamber; and a fluid connection between the pressure-control unit and the distributor unit in order to guide the gaseous fuel at a constant output pressure downstream towards the distributor unit. The device is characterized in that a flow-control valve is disposed along the fluid connection and designed to adjust the constant output pressure level of the gaseous fuel to a desired target pressure not exceeding the output pressure level.

The application discloses a step variable pressure type micro-channel heat dissipation structure and a high-power laser cut-off light screen, and the structure comprises a flow channel (3), a gradually widened micro-channel (4), a first step variable pressure structure (5) and a second step variable pressure structure (6). The first step variable pressure structure (5) and the second step variable pressure structure (6) comprise a plurality of step-by-step increased elliptical cylinder arrays, the number of the elliptical cylinders is step-by-step increased, the length of the short axis of the elliptical cylinder is step-by-step decreased, the fluid flow cross-sectional area is step-by-step decreased, and the flow speed is step-by-step increased to form a jet effect to accelerate the fluid, and finally the fluid enters the gradually widened micro-channel (4) at a higher flow speed to realize flow heat exchange. The step variable pressure structure with the step-by-step increased number of elliptical cylinders, the step-by-step decreased length of the short axis and the step-by-step decreased total flow cross-sectional area at the micro-channel inlet section can rapidly and gradiently increase the pressure to accelerate the fluid, and effectively solve the problems of excessive and concentrated pressure at the micro-channel inlet.

A variable pressure controlled injection method, a semi-finished injection product, and a co-injection product manufacturing method are provided. The variable pressure controlled injection method includes providing an injection molding system, injecting a first foaming material, and performing a foaming step. The injection molding system includes a first variable pressure mold and a second variable pressure mold. In the foaming step, the first variable pressure mold and the second variable pressure mold apply a first pressure and a second pressure to the first foaming material respectively, and then the first foaming material is heated to form a semi-finished injection product. The semi-finished injection product includes a microporous layer and a solidified layer. The co-injection product manufacturing method includes injecting a second foaming material onto the semi-finished injection product and heating under a stable internal pressure to complete foam and obtain a co-injection product.

The application discloses a pressure curve combined air separation variable pressure intelligent adsorption blowdown method, system and device, relates to the intelligent blowdown technical field.The pressure curve combined air separation variable pressure intelligent adsorption blowdown method, system and device, comprising the following steps: S1, real-time acquisition operation state data, and pretreatment is carried out to operation state data;S2, operation state data is analyzed to pressure disturbance intensity;S3, through real-time analysis and feature extraction to pressure curve;S4, operation state data is predicted to start-stop risk;S5, comprehensive operation state data, pressure disturbance intensity analysis result and start-stop risk prediction result execute blowdown control instruction.The air compressor and variable pressure adsorption system lack linkage control based on pressure change, blowdown is easy to cause pressure fluctuation and frequent start-stop, which leads to energy consumption increase and equipment wear, and the existing control mode lacks feedforward regulation mechanism.

The utility model discloses an outdoor high-safety transformer, which relates to the technical field of transformers and comprises a transformer body, and a protection mechanism is arranged at the bottom of the transformer body. The transformer body comprises a protective shell, the top of the protective shell is fixedly connected with an accelerated ventilation mechanism, and the top of the accelerated ventilation mechanism is fixedly connected with a connecting pipe. Through the cooperation of the protective shell, the connecting pipe, the material storage box, the material changing port, the ventilation port, the temperature detector, the motor and the fan, when the temperature detector detects that the voltage transformation element works too hot, the motor is started, the fan is driven to rotate, external air enters the material storage box through the ventilation port, adsorption materials are stored in the material storage box, and the adsorption materials are stored in the material storage box. According to the transformer, impurities in external air are filtered out, moisture in the air is reduced, then the air enters the protective shell through the connecting pipe and the shell, circulation of the air in the protective shell is accelerated, aging of the transformer is delayed, the probability that the transformer breaks down due to overheating is reduced, and the transformer is higher in safety and longer in service life.

A device for stimulating a human erogenous zone includes a housing; a drive device; a pressure chamber at least partially surrounded by a chamber wall; a chamber wall portion, the drive device to cause the chamber wall portion to repeatedly move between different wall positions to cause a volume of the pressure chamber to vary to cause pressure in the pressure chamber to modulate between positive pressures and negative pressures relative to an ambient pressure; a housing opening, the positive pressures and the negative pressures to be output via the housing opening; and a seal to seal the pressure chamber with respect to an ambient environment, the drive device including a coil through which an electrical current is to flow, the drive device disposed in a magnetic field and coupled to the chamber wall portion to transmit the drive movement to cause the chamber wall portion to move.

This invention proposes a variable-pressure two-body hydrostatic experimental device, belonging to the field of fluid mechanics experimental apparatus technology. The experimental device includes a main housing, within which are a first measuring chamber and a second measuring chamber. The main housing is equipped with a first air bladder and a second air bladder, as well as a first pressure measuring tube, a first U-shaped tube, a second pressure measuring tube, and a second U-shaped tube. The main housing has a first injection port and a second injection port, respectively connected to the first and second measuring chambers, and both the first and second injection ports are equipped with sealing elements. The purpose of this invention is to provide a variable-pressure two-body hydrostatic experimental device that makes hydrostatic experiments more practical and convenient, allows for wider placement, simplifies operation steps, improves experimental efficiency, and thus effectively saves time and costs, improving classroom efficiency.

The utility model discloses a series-connection pressure ratio variable low-fluctuation supercharger which comprises a pressure applying end and a pressed end. The pressure applying end comprises a first pressure applying end and a second pressure applying end, the first pressure applying end and the second pressure applying end are connected in series through a pipeline, and a first piston rod of the first pressure applying end extends into an inner cavity of the pressed end; the sectional area of the pressurizing cavity of the second pressure applying end is larger than the sectional area of the inner cavity of the pressed end and smaller than the sectional area of the pressurizing cavity of the first pressure applying end. The supercharger has different pressure ratios of low pressure and high pressure, corresponding pressure ratios can be selected under different working conditions, the pressure fluctuation value can be reduced, especially the low-pressure working condition, and the product forming quality is improved.

The present invention relates to the field of searchlight technology, and particularly to an intelligent searchlight, which includes a lamp housing, a fan plate, a fixed shaft, and a plurality of telescopic rods. A sealed cavity is provided inside the lamp housing. The fan plate is fixedly installed on the lamp housing. The fan plate is fan-shaped. A groove is formed on the plane of the fan plate of the lamp housing. The fan plate is perpendicular to the fixed shaft, and the fixed shaft penetrates through the fan plate along its own axial direction. The fixed shaft is rotatably arranged in the lamp housing and is located outside the cavity. The plurality of telescopic rods are fixedly installed on the fixed shaft. The telescopic rods can rotate and slide into the groove and are slidably connected to the fan plate. A chamber with variable pressure is provided between two adjacent telescopic rods located in the groove. The groove formed on the fan plate can increase the contact area between the cavity and the outside world and improve the heat dissipation effect of the cavity. When the telescopic rods enter the groove, as the telescopic rods continue to extend, the volume of the chamber between two adjacent telescopic rods in the groove will increase, and the pressure will gradually decrease, thereby reducing the temperature in the chamber and improving the heat dissipation efficiency of the cavity again.

The invention relates to the technical field of engineering machinery, in particular to an electric control proportional steering brake valve based on hydraulic transmission and a control method, an electric proportional pressure reducing valve is adopted to replace a traditional hydraulic control pilot handle, and the electric proportional pressure reducing valve outputs pilot pressure oil with variable pressure according to an operation instruction to push an active valve element A and an active valve element B to act; the active valve core A pushes the brake valve core to act, and power pressure oil is communicated with the brake to realize braking; the driving valve element B pushes the steering valve element to act, and main power pressure oil is communicated with a steering clutch to achieve steering. Pilot pressure output to a steering and braking unit is accurately controlled through an electric signal, and linear proportional adjustment of pressure and current is achieved. Through the design of double-spring pressure regulation and oil way separation, not only is the fine adjustment smoothness in the low-pressure stage ensured, but also the pressure is quickly increased at a key threshold value to prevent the clutch from slipping, and meanwhile, the damage of high temperature and impurities of a main oil way to a precise control element is effectively isolated, so that the control precision, response stability and reliability of a system are remarkably improved.

The invention relates to the technical field of variable-pressure plunger pumps, in particular to a pressure control system and method based on a stepless variable-pressure plunger pump, and aims at solving the problems that in the prior art, an electro-hydraulic servo system is complex in structure, high in manufacturing cost and poor in performance. According to the pressure control system based on the stepless variable pressure plunger pump, the stepless variable pressure plunger pump is provided with a liquid outlet and a liquid inlet, and the stepless variable pressure plunger pump is used for receiving a control signal and is set to be a constant-pressure variable pump of the corresponding pressure grade till the output pressure of the liquid outlet of the stepless variable pressure plunger pump reaches the preset pressure; a liquid outlet of the stepless variable-pressure plunger pump is communicated with an inlet of the proportional overflow valve, an outlet of the proportional overflow valve is communicated with a liquid inlet of the stepless variable-pressure plunger pump, and the proportional overflow valve is used for controlling the pressure of the output end of the stepless variable-pressure plunger pump. The pressure control system and method based on the stepless variable-pressure plunger pump are used for pressure adjustment of the stepless variable-pressure plunger pump.

The invention discloses a variable pressure thermal state calibration wind tunnel control system and a control method. The system comprises a variable pressure control module which is used for realizing dynamic cooperative adjustment of total pressure and back pressure of a test section; the electric heating series combustion heating module is in airflow communication with the variable pressure control module and is used for heating the test airflow in stages; the control platform is in communication connection with the variable pressure control module and the electric heating series combustion heating module and is used for realizing integrated control of the system; the health management and safety interlocking module is connected with the control platform and used for monitoring the operation state of the system and executing safety interlocking; and the visual monitoring module is used for carrying out visual monitoring on the test process. High-precision dynamic cooperative adjustment of total pressure and back pressure, wide-temperature-range uniform heating of series connection of electric heating and combustion heating and multi-system deep integration and intelligent cooperative control are achieved, and the reliability, safety and long-time continuous operation capacity of the system are remarkably improved.

The invention discloses a compressed air energy storage system which comprises a compressor unit, the compressor unit comprises a first-stage compressor, a second-stage compressor, a third-stage compressor and a fourth-stage compressor which are connected in sequence and is used for compressing air, the first-stage compressor and the second-stage compressor operate in a mode of variable-frequency starting and fixed-frequency operation, and the pressure ratio is not changed in the operation process; and the third-stage compressor and the fourth-stage compressor operate in a variable-frequency starting and variable-frequency operation mode, and the pressure ratio is changed during operation. And the expansion unit comprises a first turbine and a second turbine and is used for expansion acting, and the first turbine is provided with adjustable guide vanes. The system is reasonable in structural design, can guarantee constant power output, and has the advantages of high energy storage density, high system efficiency and low investment cost.

The invention relates to the technical field of bearings, and discloses a fixed-range rotating linear bearing which comprises an outer ring, a retainer rotationally and horizontally moving in the outer ring and stoppers located at the two ends of the outer ring and used for limiting the retainer from disengaging, a plurality of rolling bodies are assembled on the retainer, and a bidirectional dynamic buffer module is arranged on the outer ring. The two-way dynamic buffering module comprises two sets of telescopic pressure bins and a medium conveying channel arranged in the outer ring, each telescopic pressure bin comprises a hard bin chamber, a hard abutting ring and a telescopic ring piece connected with the hard bin chamber and the hard abutting ring in a sealed mode, and a medium channel communicating with the medium conveying channel and the annular variable pressure bin is arranged in each hard bin chamber; the telescopic ring piece, the annular variable-pressure bin and the medium conveying channel are filled with media, when the holder abuts against the hard abutting ring, the hard abutting ring extrudes the media in the annular variable-pressure bin till the media make contact with the hard bin, the bearing has the functions of rotation and reciprocating translation in a fixed range, rotation is smooth, and the translation buffering performance is good.

The utility model relates to an air supply system with variable compressed air. The air supply system comprises a first compressed air pipeline, a second compressed air pipeline, a main air supply pipeline, an auxiliary air supply pipeline, a communicating pipeline, an auxiliary electromagnetic valve and a control circuit used for controlling the auxiliary electromagnetic valve, the first end of the main air supply pipeline is connected with a first compressed air pipeline, the first end of the auxiliary air supply pipeline is connected with a second compressed air pipeline, the second end of the main air supply pipeline and the second end of the auxiliary air supply pipeline are both connected with the first end of the communicating pipeline, and the second end of the communicating pipeline is connected to a position needing air supply; the auxiliary electromagnetic valve is arranged on the auxiliary air supply pipeline, and the control circuit is connected with the auxiliary electromagnetic valve. According to the utility model, compressed air with variable pressure can be provided as required, so that the stability of process production is met, and the compressed air usage amount is saved.

The utility model provides a winding device for a transformer winder, and relates to the technical field of transformer windings, the winding device comprises a bottom plate, a support frame and a fixing frame, the top of the support frame is provided with a rotary winding mechanism, the rotary winding mechanism is provided with a transformer winding, and the top of the fixing frame is provided with a guide wheel through a guide mechanism; the guide wheel is connected with the output end of the second air cylinder into a whole through the telescopic rod and the connecting arm, the output end of the second air cylinder can drive the guide wheel to horizontally move in a reciprocating mode so as to adjust the distance between the guide wheel and the transformer winding, the guide wheel can be attached to the outer side of the transformer winding, and the telescopic rod and the spring are both in a compressed state. The transformer winding is generally of a square structure and can extrude the guide wheel to do telescopic motion in the rotating process, the guide wheel is driven to reset through the telescopic rod by means of elastic force generated by the spring, the guide wheel is attached to the outer side of the transformer winding all the time, and copper foil is wound more tightly.

This invention discloses a variable pressure airtight chamber and testing method for testing the three properties of doors and windows. The chamber includes a main body and a testing chamber within it. A testing opening communicating with the testing chamber is located on at least one side of the main body. A door / window mounting portion for engaging with the outer periphery of a door or window is located at the testing opening. The mounting portion includes an inflatable airbag for engaging with the outer periphery of the door or window. The invention also includes an airbag inflation / deflation mechanism for driving the inflatable airbag to inflate outwards. By providing an inflatable airbag for engaging with the outer periphery of the door or window in the mounting portion, this invention achieves a tight seal between the door / window and the mounting portion when the airbag inflates, preventing air leakage from affecting testing accuracy. This also makes door / window installation and disassembly more convenient and improves testing efficiency.