Bubble forming device and method by tube braking method

Abstract

The invention discloses a tube braking method bubble making device and method in the field of bubble making devices, the tube braking method bubble making device comprises a water tank, a glass tube, a sliding assembly and a slender rod, the water tank is filled with liquid, the glass tube is installed on the sliding assembly, vertical movement of the glass tube is achieved through the sliding assembly, and the opening end of the glass tube is arranged in the liquid of the water tank; a groove for storing a gas nucleus is formed in one end part of the slender rod; and the groove is positioned at the opening end of the glass tube when the tube is braked. According to the tube braking method bubbling device, movement and tube braking of the glass tube are achieved through the sliding assembly, a low-pressure area is generated in the test tube, cavitation bubbles are generated under the action of the low-pressure area and a gas nucleus on the slender rod, generation and collapse of the cavitation bubbles in the water tank are not limited by space, the device is more stable, the experiment requirement is met, and the experiment efficiency is improved. And the success rate and the foaming efficiency of the foaming device are improved.

Description

Technical Field

[0001] The invention relates to the field of bubble generating devices, and in particular to a bubble generating device and method using a brake pipe method. Background Art

[0002] Cavitation is a phenomenon in which bubbles form and quickly collapse in liquids, and it is widely seen in many fluid mechanics, engineering, and biomedical applications. The growth and collapse of cavitation bubbles is a complex process that involves the temperature, pressure, thermodynamic state, and fluid state inside and outside the bubble. During the collapse of cavitation bubbles near the wall, extremely high local temperatures and pressures are generated, accompanied by high-intensity jets impacting the wall, which directly affect the working efficiency of the equipment. Therefore, studying the growth and collapse process of cavitation bubbles helps to gain a deeper understanding of cavitation behavior and its impact on materials and equipment. The damage mechanism of cavitation to equipment can be better predicted, thereby optimizing design and protection measures.

[0003] The "brake tube method" is a classic cavitation experimental method. The principle is to induce cavitation by controlling the rapid change of local pressure in a thin glass tube. It was originally used to observe the "sonoluminescence" phenomenon and is now widely used to study the formation mechanism of cavitation bubbles and their impact on fluid flow. However, the traditional "brake tube method" device has some limitations.

[0004] like Figure 4 The present invention shows a conventional bubble-generating device of the brake tube method. The test tube 13 is mounted on the vertical rod 14 through a clamp 16. A top plate 15 is provided at the top of the vertical rod 14. The top plate 15 and the clamp 16 are respectively mounted with two ends of a spring. A thin rod is fixed on the top plate 15. One end with a groove extends into the liquid inside the test tube 13. The test tube 13 moves upward and is then restricted by a block 17 to stop the downward movement. The water in the test tube continues to move upward, generating a low-pressure area at the bottom of the test tube. The low-pressure area moves upward and acts on the groove on the thin rod to form cavitation bubbles. The growth and collapse of the cavitation bubbles are affected by the test tube wall, which makes it difficult for the characteristics of the cavitation bubbles to be captured by a high-speed camera and thus cannot be accurately measured. In addition, due to the narrow space in the test tube, it is impossible to install sensors to accurately measure certain physical quantities. These problems limit the depth and breadth of cavitation research to a certain extent, especially under the requirements of high-precision experiments, and cannot provide a stable cavitation bubble generation process.

[0005] For example, cavitation bubbles are usually generated at the bottom of a thin glass tube. The growth and collapse of cavitation bubbles are affected by the glass tube wall, making it difficult for high-speed cameras to capture the characteristics of cavitation bubbles and thus unable to accurately measure them. In addition, due to the narrow space in the glass tube, it is impossible to install sensors to accurately measure certain physical quantities. These problems have limited the depth and breadth of cavitation research to a certain extent, especially under high-precision experimental requirements, and cannot provide a stable cavitation bubble generation process. Summary of the invention

[0006] The object of the present invention is to provide a brake pipe method bubble generating device and method, the generation and collapse of cavitation bubbles are both realized in a water tank, the water tank has a large space, the cavitation bubbles are more stable, and experimental observation and analysis are convenient.

[0007] In order to solve the above technical problems, the following technical solutions are adopted: In a first aspect, the present invention provides a brake tube method bubble generating device, comprising a water tank, a glass tube, a sliding assembly and a thin rod, wherein the water tank is filled with liquid, the glass tube is mounted on the sliding assembly, and the sliding assembly is used to realize the up and down movement of the glass tube and the brake tube, one end of the glass tube is closed, and the other end is open, and the open end is arranged in the liquid in the water tank; A groove for storing gas cores is provided on one end of the thin rod, and the groove is placed in the liquid in the water tank; when the glass tube is braked, the groove is located outside the open end of the glass tube.

[0008] Optionally, the open end of the glass tube is connected with a trumpet-shaped opening.

[0009] Optionally, the closed end of the glass tube is sealed with a sealing rubber plug, one end of the thin rod away from the groove is connected to the sealing rubber plug, and one end of the thin rod provided with the groove is arranged at the trumpet-shaped opening of the glass tube.

[0010] Optionally, one end of the thin rod away from the groove is mounted on a thin rod fixing device, the thin rod fixing device is arranged in the water tank, and the groove is located directly below the open end of the glass tube.

[0011] Optionally, the sliding assembly includes a horizontal bracket for mounting the glass tube, a metal sliding rod for mounting the horizontal bracket, and a blocking block arranged on the metal sliding rod, the horizontal bracket moves up and down on the metal sliding rod, thereby realizing the up and down movement of the glass tube, the blocking block is used to limit the movement of the horizontal bracket on the metal sliding rod, and the blocking block is detachably mounted on the metal sliding rod.

[0012] Optionally, two metal slide bars are provided, each of which is provided with the blocking block, the two metal slide bars and the water tank are arranged on the water tank placement platform, and the three are located on the same straight line, and the water tank is located between the two metal slide bars.

[0013] Optionally, both ends of the horizontal bracket are respectively slidably connected to the two metal sliding bars, and the metal sliding bars are further provided with springs, which are located above the horizontal bracket, and one end of the spring away from the horizontal bracket is connected to the metal sliding bar.

[0014] Optionally, the glass tube is installed in the middle of the horizontal support through a glass tube fixture.

[0015] Optionally, the water tank is made of a highly light-transmitting material.

[0016] In a second aspect, the present invention provides a brake pipe method for generating bubbles, which is implemented by using the brake pipe method for generating bubbles device according to any one of the first aspects, and comprises the following steps: The glass tube is filled with liquid by using atmospheric pressure, and the position of the glass tube filled with liquid is restricted by a sliding assembly; Apply force to the sliding assembly to move the glass tube toward the bottom of the water tank, and the glass tube moves a certain distance to the rear brake pipe; The liquid in the end of the glass tube away from the open end continues to move downward due to inertia, forming a low-pressure area in the glass tube; This low-pressure area then propagates through the liquid at the speed of sound until it reaches the open end of the glass tube and then acts on the end of the thin rod that has the groove; The gas core stored in the groove on the end of the thin rod forms cavitation bubbles under the action of the low pressure area; By adjusting the position of the glass tube brake tube, different cavitation bubbles can be generated for research, and by using a plurality of the thin rods and the grooves, a plurality of cavitation bubbles can be generated simultaneously.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The brake tube method bubble-generating device provided by the present invention realizes the movement and brake tube of the glass tube through a sliding component, thereby generating a low-pressure area. The low-pressure area reacts with the gas nuclei on the thin rod to generate cavitation bubbles. The generated cavitation bubbles are in the water tank, which is convenient for experimental equipment to measure and observe. During the experiment, different cavitation bubbles can be generated by adjusting the position of the glass tube when the brake tube is used to study the influencing factors of the cavitation bubbles. The generation and collapse of cavitation bubbles in the water tank will not be limited by space, which is more stable, meeting the experimental requirements, and improving the success rate and bubble-generating efficiency of the bubble-generating device.

[0018] 2. The present invention sets a spring on the horizontal support to make the liquid in the glass tube obtain downward acceleration, so that the local pressure in the glass tube is reduced. The set blocking block can change its position on the metal slide bar, thereby changing the variable of generating cavitation bubbles, studying the influencing factors of cavitation bubble generation, and meeting the requirements of repeated experiments under different experimental conditions. Better improve the refinement of the experiment.

[0019] 3. The present invention can increase the number of thin rods and adjust the positions of the thin rods to make them symmetrical in the low-pressure area generated by the glass tube, thereby making it easier to obtain two or more cavitation bubbles with relatively synchronous growth and collapse processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the brake pipe method foaming device in Example 2 of the present invention; Figure 2 It is a schematic diagram of the structure of the brake pipe method foaming device in Example 3 of the present invention; Figure 3 The present invention Figure 2 and Figure 3 A is a schematic diagram of a partially enlarged groove structure; Figure 4 It is a structural schematic diagram of the existing brake pipe method bubble generating device of the present invention.

[0021] Description of reference numerals: 1. Glass tube; 2. Water tank; 3. Thin rod; 4. Metal slide bar; 5. Horizontal bracket; 6. Stop block; 7. Spring; 8. Water tank placement platform; 9. Glass tube holder; 10. Sealing rubber plug; 11. Thin rod fixing device; 12. Groove; 13. Test tube; 14. Vertical rod; 15. Top plate; 16. Clamp; 17. Stop block. DETAILED DESCRIPTION

[0022] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Example 1

[0023] like Figure 1 and Figure 3 As shown, this embodiment provides a brake tube method bubble generating device, comprising a water tank 2, a glass tube 1, a sliding assembly and a thin rod 3, wherein the water tank 2 is filled with liquid, the glass tube 1 is mounted on the sliding assembly, and the glass tube 1 is moved up and down and braked by the sliding assembly, and the open end of the glass tube 1 is arranged in the liquid of the water tank 2; A groove 12 for storing the gas core is provided on one end of the thin rod 3, and the groove 12 is placed in the liquid of the water tank 2; The groove 12 is located at the open end of the glass tube 1 when the glass tube is braked.

[0024] The groove 12 is placed in the liquid of the water tank 2, and a force is applied to the sliding component 5 to make the glass tube 1 move downward. After the glass tube 1 moves downward for a distance, the liquid in the glass tube 1 continues to move downward due to inertia, thereby generating a low-pressure area in the glass tube 1. The low-pressure area acts on the groove 12 to generate cavitation bubbles. The cavitation bubbles are in the water tank 2, with a large activity space, and the cavitation bubbles are more stable, making it easier to observe the changes in the cavitation bubbles and analyze the formation and influencing factors of the cavitation bubbles. A high-speed camera is set outside the water tank 2 to observe the growth and collapse of the cavitation bubbles in the water tank 2, and a sensor can also be installed in the water tank 2 to measure physical quantities such as the temperature, pressure, and moving speed of the cavitation bubbles. In this way, the physical properties of the cavitation bubbles can be obtained more comprehensively, and the research on the cavitation bubbles can be more accurate. Example 2

[0025] This embodiment provides a brake pipe method bubble generating device based on the embodiment 1, the difference is that: like Figure 1 As shown, the sliding assembly includes a horizontal bracket 5 for mounting the glass tube 1, a metal slide bar 4 for mounting the horizontal bracket 5, and a blocking block 6 arranged on the metal slide bar 4. The horizontal bracket 5 moves up and down on the metal slide bar 4, thereby realizing the up and down movement of the glass tube 1. The blocking block 6 is used to limit the movement of the horizontal bracket 5 on the metal slide bar 4. The blocking block 6 is detachably mounted on the metal slide bar 4.

[0026] The open end of the glass tube 1 is trumpet-shaped, and the other end is closed. The open end is placed in a water tank 2, and a thin rod 3 is arranged directly below the open end. One end of the groove 12 on the thin rod 3 is close to the open end, and the other end of the thin rod 3 is mounted on a thin rod fixing device 11, which is arranged at the bottom of the water tank 2. When the glass tube 1 stops after moving, the low-pressure area generated comes out of the open end of the glass tube 1 and acts on the gas core on the groove 12 on the thin rod 3, thereby forming a cavitation bubble. The formed cavitation bubble is stable and not limited by space, which is convenient for measuring and studying the cavitation bubble. By changing the position of the thin rod 3 and the glass tube 1 in the water tank 2, the influencing factors of the cavitation bubble are changed for research.

[0027] There are two metal slide bars 4, and the two metal slide bars 4 and the water tank 2 are arranged on the water tank placement platform 8, and the three are located on the same straight line, and the water tank 2 is located between the two metal slide bars 4. The two ends of the horizontal bracket 5 are respectively sleeved on the two metal slide bars 4, and the horizontal bracket 5 is moved manually to achieve movement on the metal slide bars 4. When no force is applied to the horizontal bracket 5, the horizontal bracket 5 and the glass tube 1 arranged thereon can be stably placed on the metal slide bars 4. The glass tube 1 is installed in the middle position of the horizontal bracket 5 through the glass tube holder 9, and the open end of the glass tube 1 is downward and placed in the water tank 2.

[0028] A spring 7 is provided on each of the two metal slide bars 4. The spring 7 is located above the horizontal bracket 5. One end of the spring 7 away from the horizontal bracket 5 is connected to the metal slide bar 4. When an upward force is applied to the horizontal bracket 5, the spring 7 is compressed by the horizontal bracket 5. The compressed spring 7 exerts a downward force on the horizontal bracket 5 due to the elastic force, and then the horizontal bracket 5 moves downward with the glass tube 1. When the horizontal bracket 5 contacts the blocking block 6, the horizontal bracket 5 and the glass tube 1 stop moving downward. The liquid in the glass tube 1 continues to move downward due to inertia. The liquid moves downward from the glass tube 1, and a low-pressure area is formed on the top of the glass tube 1. The low-pressure area moves toward the open end of the glass tube 1. After moving to the open end, it acts on the groove 12 at the end of the thin rod 3 to form a cavitation bubble with the gas core on the groove 12.

[0029] During the experiment, a high-speed camera needs to be installed outside the water tank 2 to record the generation and collapse of cavitation bubbles. The water tank 2 used is made of high-light-transmittance material to facilitate the recording of the high-speed camera.

[0030] In this embodiment, the glass tube 1 is moved by sliding the horizontal bracket 5 on the metal slide bar 4, and the glass tube 1 is stopped by the provided blocking block 6 to brake the glass tube. The position of the blocking block 6 on the metal slide bar 4 is adjustable. By adjusting the position of the blocking block 6, the low pressure area generated in the glass tube 1 is adjusted, thereby adjusting the factors of cavitation bubble production. The relative position of the glass tube 1, the water tank 2 and the sliding component can be adjusted to study the factors affecting the generation of cavitation bubbles.

[0031] When in use, the length of the glass tube 1 used and the position where the glass tube 1 is installed, the elastic force of the spring 7 used, the position of the blocking block 6 and the position of the thin rod 3 can all be adjusted as needed to obtain cavitation bubbles of different sizes. A certain amount of data results can be obtained on the basis of repeated experiments to verify whether the theory and simulation model are reliable, and repeated experiments can be performed multiple times under different experimental requirements. The refinement of the experiment can be better improved. One or more different types of sensors can be placed in the water tank 2 to further study the specific changes in certain physical quantities. Combined with the shooting of a high-speed camera, the theory of the cavitation model or the fluid model can be further verified, which can make up for the shortcomings of existing research. The present embodiment can also increase the number of thin rods 3 and adjust the position of the thin rods 3 to make them symmetrical in the low-pressure area, so that it is easier to obtain two or more cavitation bubbles with relatively synchronous growth and collapse processes. Example 3

[0032] This embodiment provides a brake pipe method bubble generating device based on the embodiment 1, the difference is that: like Figure 2 and Figure 3As shown, one end of the glass tube 1 used is closed by a sealing rubber plug 10, and the other end is trumpet-shaped. The end of the thin rod 3 away from the groove 12 is connected to the sealing rubber plug 10, and the end with the groove 12 is arranged at the open end of the glass tube 1. The open end of the glass tube 1 is trumpet-shaped. The thin rod 3 moves with the glass tube 1. The low-pressure area generated in the glass tube 1 moves toward the open end. When moving to the open end, it reacts with the gas core on the groove 12 to form cavitation bubbles. The cavitation bubbles move above the water tank 2 and are recorded by a high-speed camera outside the water tank 2. Example 4

[0033] This embodiment provides a brake pipe method for generating bubbles, which is implemented by using the brake pipe method for generating bubbles device of embodiment 2 or embodiment 3, and includes the following steps: The glass tube 1 is filled with liquid by using atmospheric pressure, and the position of the glass tube 1 filled with liquid is restricted by a sliding component; Apply force to the horizontal support 5, so that the glass tube 1 moves toward the bottom of the water tank 2, and the brake tube is braked after the glass tube moves a certain distance; The liquid in the end of the glass tube 1 away from the open end continues to move downward due to inertia, forming a low-pressure area in the glass tube 1; This low pressure area then propagates in the liquid at the speed of sound until it reaches the open end of the glass tube 1 and then acts on the end of the thin rod 3 provided with the groove 12; The gas core stored in the groove 12 at the end of the thin rod 3 forms cavitation bubbles under the action of the low pressure area. By adjusting the position of the glass tube brake tube, different cavitation bubbles can be generated for research, and by using a plurality of the thin rods and the grooves, a plurality of cavitation bubbles can be generated simultaneously.

[0034] In the above steps, a portion of the glass tube 1 is located below the horizontal plane of the water tank 2, and one end is located above the horizontal plane. The space above the horizontal plane of the glass tube 1 is also filled with liquid using the principle of atmospheric pressure and is installed through a horizontal bracket 5.

[0035] In the above steps, an upward force is applied to the horizontal bracket 5, so that the horizontal bracket 5 compresses the spring 7 and then moves downward. The horizontal bracket 5 moving downward is restricted by the blocking block 6, thereby stopping the downward movement. However, the water inside the glass tube 1 continues to move downward due to inertia, and the water at the top of the glass tube 1 continues to move downward. After the water moves downward, a low-pressure area is formed at the top of the glass tube 1.

[0036] This low-pressure area then propagates in the liquid at the speed of sound until it reaches the open end of the glass tube 1, and the gas core stored at the top of the thin rod 3 forms a cavitation bubble under the action of the low-pressure area.

[0037] The formed cavitation bubbles move in the water tank 2, moving toward the horizontal plane or the side wall of the water tank 2. Since the space of the water tank 2 is large, the generation and collapse of the cavitation bubbles are not limited by space, are relatively stable, and are convenient to record. A high-speed camera is installed outside the water tank 2 to record the cavitation bubbles, so as to study the generation and collapse process of the cavitation bubbles and changes in the surrounding environment. Different sensors can be installed on the side wall of the water tank 2 to measure the physical quantities of the cavitation bubbles.

[0038] When using the brake tube method bubble generating device, different cavitation bubbles can be generated by changing the length of the glass tube 1, its position in the water tank 2 and the position of the blocking block 6. Through repeated experiments, the influencing factors of cavitation bubbles can be determined.

[0039] During the experiment, multiple thin rods 3 can be arranged in the water tank 2, and each thin rod 3 is provided with a groove 12. When the low-pressure area generated in the glass tube 1 acts on the multiple thin rods 2, a cavitation bubble is generated at the groove 12 of each thin rod 2, and the thin rods 2 are arranged symmetrically with respect to the center of the glass tube 1, that is, the positions of the thin rods make them symmetrical in the low-pressure area generated by the glass tube. The multiple cavitation bubbles generated on the thin rods 2 are completely synchronized, and the synchronous generation and collapse of multiple cavitation bubbles can be achieved, which is more convenient for the observation and study of cavitation bubbles.

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A brake pipe method bubble generating device, characterized in that: It includes a water tank, a glass tube, a sliding assembly and a thin rod. The water tank is filled with liquid. The glass tube is installed on the sliding assembly. The sliding assembly is used to realize the up and down movement of the glass tube and the brake tube. One end of the glass tube is closed and the other end is open, and the open end is set in the liquid in the water tank. A groove for storing gas cores is provided on one end of the thin rod, and the groove is placed in the liquid in the water tank; when the glass tube is braked, the groove is located outside the open end of the glass tube.

2. The brake pipe method bubble generating device according to claim 1, characterized in that: The open end of the glass tube is connected with a trumpet-shaped opening.

3. The brake pipe method bubble generating device according to claim 2, characterized in that: The closed end of the glass tube is sealed with a sealing rubber plug, one end of the thin rod away from the groove is connected to the sealing rubber plug, and one end of the thin rod provided with the groove is arranged at the trumpet-shaped opening of the glass tube.

4. The brake pipe method bubble generating device according to claim 2, characterized in that: One end of the thin rod away from the groove is installed on a thin rod fixing device, and the thin rod fixing device is arranged in the water tank. The groove is located directly below the open end of the glass tube.

5. The brake pipe method bubble generating device according to claim 1, characterized in that: The sliding assembly includes a horizontal bracket for mounting the glass tube, a metal sliding rod for mounting the horizontal bracket, and a blocking block arranged on the metal sliding rod. The horizontal bracket moves up and down on the metal sliding rod, thereby realizing the up and down movement of the glass tube. The blocking block is used to limit the movement of the horizontal bracket on the metal sliding rod, and the blocking block is detachably mounted on the metal sliding rod.

6. The brake pipe method bubble generating device according to claim 5, characterized in that: There are two metal slide bars, each of which is provided with the blocking block. The two metal slide bars and the water tank are arranged on the water tank placement platform, and the three are located on the same straight line, and the water tank is located between the two metal slide bars.

7. The brake pipe method bubble generating device according to claim 5, characterized in that: The two ends of the horizontal bracket are respectively slidably connected to the two metal sliding bars. The metal sliding bars are also provided with springs, which are located above the horizontal bracket. One end of the spring away from the horizontal bracket is connected to the metal sliding bar.

8. The brake pipe method bubble generating device according to claim 5, characterized in that: The glass tube is installed in the middle of the horizontal support through a glass tube fixture.

9. The brake pipe method bubble generating device according to claim 1, characterized in that: The water tank is made of highly light-transmitting material.

10. A method for generating bubbles by brake pipe method, characterized in that: The method is implemented by using the brake pipe method bubble generating device according to any one of claims 1 to 8, comprising the following steps: The glass tube is filled with liquid by using atmospheric pressure, and the position of the glass tube filled with liquid is restricted by a sliding assembly; Apply force to the sliding assembly to move the glass tube toward the bottom of the water tank, and the glass tube moves a certain distance to the rear brake pipe; The liquid in the end of the glass tube away from the open end continues to move downward due to inertia, forming a low-pressure area in the glass tube; This low-pressure area then propagates through the liquid at the speed of sound until it reaches the open end of the glass tube and then acts on the end of the thin rod that has the groove; The gas core stored in the groove on the end of the thin rod forms cavitation bubbles under the action of the low pressure area; By adjusting the position of the glass tube brake tube, different cavitation bubbles can be generated for research, and by using a plurality of the thin rods and the grooves, a plurality of cavitation bubbles can be generated simultaneously.

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