Side hanging type high-altitude wind energy driving device and acting system

Abstract

The invention relates to a side hanging type high-altitude wind energy driving device and an acting system. The driving device comprises a sliding mechanism and a driving mechanism which are connected to an acting umbrella. The sliding mechanism is arranged to freely slide along a main cable, is connected to the periphery of the acting umbrella and is used for synchronously sliding along the main cable with the acting umbrella; the driving mechanism is fixedly arranged on the main cable below the sliding mechanism, is connected with a plurality of parachute periphery parachute cords arranged on the parachute periphery of the acting parachute, and is used for pulling the parachute periphery parachute cords; the umbrella top of the acting umbrella is connected to the driving module mechanism through a pulling rope, and the driving module mechanism controls the pulling rope to be wound and unwound. The mode that the driving mechanism is fixed and the acting umbrella is laterally hung is adopted, abrasion to a main cable and driving energy consumption are reduced, rotation of an umbrella cover of the acting umbrella is avoided, and the risk of winding of an umbrella rope is eliminated.

Description

Technical Field

[0001] The present disclosure relates to the technical field of high-altitude wind energy, and in particular to a side-mounted high-altitude wind energy driving device and a working system. Background Art

[0002] High-altitude wind energy generally refers to medium- and high-altitude wind energy above 300 meters above the ground. As altitude increases, the average wind speed increases, and the wind energy density contained therein also increases. High-altitude wind energy is a renewable energy source with abundant reserves. Harnessing high-altitude wind energy for power generation can produce highly stable, low-cost wind power. Among them, the parachute-ladder combined wind energy conversion system is a commonly used high-altitude wind energy conversion solution. This solution uses a working parachute that periodically opens and closes in the air to transfer wind energy via a main cable to a ground-based working system, thereby driving the ground-based working system to produce work and achieve high-altitude wind energy conversion.

[0003] CN200910190150.2 discloses a high-power umbrella-type wind turbine system, comprising a main cable, a lift guide, a parachute ladder, and a generator. One end of the main cable passes through the parachute ladder and is tied to the lift guide, while the other end is secured to the ground. The parachute ladder consists of one or more parasols, each spaced apart. Each parachute has an opening in its center for the main cable to pass through. When the parasols are opened, the wind creates a significant upward pull. The working parasols in the parachute ladder are connected to a working cable, the other end of which is connected to a generator, which pulls the generator into mechanical motion, converting wind energy into electrical energy.

[0004] In the above scheme, the power-generating parachute comprises two actuators, one upper and one lower, that can freely travel on the main cable. The upper actuator drives the parachute's top up and down the main cable. The parachute's circumference is connected to the lower actuator via a number of circumferential parachute lines. The lower actuator is connected to a ferrule fixed to the main cable and can be controlled to connect and disconnect with the ferrule. During deployment, the lower actuator connects to the ferrule. The high-altitude wind force acting on the parachute is transmitted to the lower actuator via the parachute lines, and then to the main cable via the ferrule. The main cable then pulls the ground system to generate power or electricity. When the aerial system reaches the upper limit of its altitude, the parachute is controlled to close. At this time, the lower actuator separates from the ferrule and rapidly ascends a certain distance, causing the power-generating parachute to fold in the wind. Simultaneously, the upper actuator descends, pushing the lower actuator to reconnect with the ferrule. The ground system then lowers the aerial module to the lower limit of its altitude. The upper actuator then ascends on the main cable to a predetermined position, and the system deploys again.

[0005] In parachute-ladder high-altitude wind power generation technology solutions, due to the heavy weight of the upper and lower drives and the need to repeatedly and rapidly travel on the main cable to precisely reach and stop at the desired position, a climbing spike belt or friction drive system is generally used. This solution not only consumes a lot of energy but also requires the drive device to have a long endurance. Furthermore, both climbing spike and friction drives cause significant wear on the main cable, affecting the long-term reliability of the system.

[0006] Furthermore, in the above and similar schemes, the main cable passes through the center of the power parachute, and the parachute inevitably rotates when subjected to uneven airflow. To prevent tangling of the parachute lines, both the upper and lower actuators must be equipped with circumferential rotation mechanisms connecting the top and circumferential lines, respectively. The inclusion of these circumferential rotation mechanisms not only increases the complexity of the system but also increases the weight of the actuators, further increasing drive energy consumption and posing a greater challenge to the system's endurance. Summary of the Invention

[0007] Based on at least one of the above technical problems, the present disclosure provides the following technical solutions:

[0008] A side-mounted high-altitude wind energy drive device comprises a sliding mechanism and a driving mechanism respectively connected to a working parachute;

[0009] The sliding mechanism is configured to slide freely along the main cable and is connected to the parachute of the power-producing parachute, so as to achieve synchronous sliding along the main cable with the power-producing parachute;

[0010] The driving mechanism is fixedly arranged on the main cable located below the sliding mechanism and is connected to a plurality of parachute lines arranged around the working parachute, and is used for pulling the parachute lines.

[0011] The top of the working parachute is connected to the driving mechanism via a traction rope, and the driving mechanism controls the retraction and extension of the traction rope.

[0012] Preferably, the parachute lines around the umbrella converge and connect to a first traction rope, and the driving mechanism is connected to the first traction rope and controls the retraction and extension of the first traction rope;

[0013] The umbrella top is evenly provided with a plurality of umbrella top parachute ropes, and the umbrella top parachute ropes converge and are connected to the second traction rope. The driving mechanism is connected to the second traction rope and controls the retraction and extension of the second traction rope.

[0014] Preferably, the driving mechanism controls the retraction and extension of the first traction rope and the second traction rope simultaneously or separately.

[0015] More preferably, it comprises a first converging mechanism and a second converging mechanism;

[0016] The parachute lines around the umbrella are connected to the first converging mechanism, and the first converging mechanism is connected to the first traction rope; the parachute lines at the top of the umbrella are connected to the second converging mechanism, and the second converging mechanism is connected to the second traction rope.

[0017] More preferably, it further comprises a transfer rope, one end of which is fixedly connected to the main cable located above the driving mechanism, and the other end of which is provided with a limiting mechanism;

[0018] The limiting mechanism is connected to the first traction rope and is used to lock the first traction rope or unlock the first traction rope.

[0019] Preferably, the limiting mechanism includes a ferrule, the first traction rope passes through the ferrule, and the first traction rope is provided with a clamping head that is clamped and connected to the ferrule.

[0020] More preferably, it further comprises a stopper provided on the main cable, wherein the stopper is used to limit the range of the sliding mechanism sliding downward along the main cable.

[0021] Preferably, the umbrella periphery of the working parachute is directly connected to the sliding mechanism; or

[0022] The umbrella circumference of the working parachute is connected to the sliding mechanism via a section of cable.

[0023] More preferably, the driving mechanism is provided with an energy storage module, which converts the kinetic energy generated when the first traction rope is released into electrical energy, at least for replenishing electrical energy for the driving mechanism.

[0024] Based on at least one of the above technical problems, the present disclosure also provides the following technical solutions:

[0025] A side-mounted high-altitude wind energy system includes a main cable and at least one working parachute. One end of the main cable is connected to an aerial guide and balance module and the other end is connected to a ground module. The working parachute uses any one of the aforementioned drive devices.

[0026] The technical solution claimed in this disclosure has achieved the following beneficial effects:

[0027] 1. The drive mechanism is fixed to the main cable. Compared to traditional walking drive mechanisms, this approach significantly reduces wear on the main cable, extending its service life while also enhancing safety and reliability. Furthermore, a single drive mechanism is required to periodically activate and deactivate the parachute. This is more energy-efficient than rope-climbing drive methods for parachutes of the same frontal area, significantly reducing the requirements for endurance devices.

[0028] 2. By using a fixed side-mounted power parachute, the parachute's rotation is completely avoided, eliminating the risk of line entanglement. Since there are no issues with parachute rotation or line entanglement, the installation of both the top and circumferential parachute lines does not require a complex and heavy circumferential rotation mechanism. Instead, a simple rope-gathering mechanism is used to converge the ends of the lines.

[0029] 3. Compared to a method where the main cable passes through the center of the power parachute, a side-mounted power parachute is easier to deploy in lower winds, meaning the system's cut-in wind speed is significantly lower. Compared to a method where the main cable passes through the center of the parachute, a side-mounted parachute is also more convenient to install, simplifies maintenance, and makes it easier to set up and adjust the parachute ladder. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings in the following description are merely embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0031] Figure 1 This is a schematic diagram of the main structure of the side-mounted high-altitude wind energy system.

[0032] Figure 2 This is a schematic diagram of the initial launch state of the side-mounted high-altitude wind energy system.

[0033] Figure 3 This is a schematic diagram of the instantaneous state of the side-mounted high-altitude wind energy system when the parachute is closed.

[0034] Figure 4 This is a schematic diagram of the reset completion status of the side-mounted high-altitude wind energy system.

[0035] Figure 5 This is a schematic diagram of the initial and subsequent parachute opening process of the side-mounted high-altitude wind energy system.

[0036] Figure 6 This is a structural diagram of a side-mounted high-altitude wind energy system with a parachute-ladder combination.

[0037] Reference numerals:

[0038] 100-air guidance and balancing module; 200-main cable; 300-working rope; 310-parachute rope; 320-first convergence mechanism; 400-second traction rope; 500-first traction rope; 510-clamp; 600-driving mechanism; 700-transmission rope; 710-clamping sleeve; 800-stopper; 900-sliding mechanism. DETAILED DESCRIPTION

[0039] To make the purpose, technical solutions, and beneficial effects of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present disclosure.

[0040] Example

[0041] This embodiment provides a driving device for a side-mounted high-altitude wind energy working system, which mainly includes a sliding mechanism and a driving mechanism respectively connected to a working parachute.

[0042] The sliding mechanism is configured to slide freely along the main cable and is connected to the perimeter of the power parachute, driving the parachute along the main cable. A drive mechanism is fixed to the main cable below the sliding mechanism and connected to a plurality of parachute lines arranged around the perimeter of the power parachute, pulling the lines. The parachute's canopy is connected to the drive mechanism via a traction line, which controls the retraction and extension of the traction line.

[0043] The parachute of the power parachute is directly connected to the sliding mechanism or connected to the sliding mechanism through a cable. A stopper is provided on the main cable to limit the range of the sliding mechanism sliding downward along the main cable.

[0044] In this embodiment, the drive mechanism is fixed to the main cable. Compared to traditional walking drive mechanisms, this approach significantly reduces wear on the main cable, extending its service life while also enhancing safety and reliability. Furthermore, a single drive mechanism is required to periodically open and close the power parachute. This makes it more energy-efficient than a rope-climbing drive for power parachutes of the same frontal area, significantly reducing the requirements for endurance devices.

[0045] Furthermore, this embodiment completely avoids canopy rotation by utilizing a fixed side-mounted power parachute, further eliminating the risk of line entanglement. Since canopy rotation and line entanglement are eliminated, neither the top nor the circumferential lines require complex and heavy circumferential rotation mechanisms. Instead, a simple line-gathering mechanism is required to converge the line ends.

[0046] Compared to methods where the main cable passes through the center of the power parachute, side-mounted power parachutes are easier to deploy in lower winds, meaning the system's cut-in wind speed is significantly reduced. Compared to methods where the main cable passes through the center of the parachute, side-mounted parachutes are also more convenient to install, simpler to maintain, and easier to set up and adjust the parachute ladder pattern. For example, when installing and removing any single aerial module, the side-mounted method generally does not require the removal or installation of other aerial modules. However, setting up and maintaining the parachute ladder with the main cable passing through the center of the parachute often requires the sequential removal and installation of multiple aerial modules, significantly increasing the workload compared to the side-mounted method.

[0047] In a preferred embodiment, the parachute lines around the umbrella converge and connect to a first traction line. A drive mechanism is connected to the first traction line and controls its retraction and extension. Several top parachute lines are evenly distributed around the umbrella's crown. These converge and connect to a second traction line. A drive mechanism is connected to the second traction line and controls its retraction and extension. The drive mechanism uses a small winch or similar mechanism to retract and extend the first and second traction lines. The drive mechanism can be configured to control the retraction and extension of the first and second traction lines simultaneously or separately.

[0048] In an exemplary configuration, the drive device can converge the first and second traction ropes via a first convergence mechanism and a second convergence mechanism, respectively. Specifically, the circumferential parachute lines are connected to the first convergence mechanism, which in turn is connected to the first traction rope, and the top parachute lines are connected to the second convergence mechanism, which in turn is connected to the second traction rope.

[0049] In a preferred embodiment, the driving device further comprises a transmission rope, one end of which is fixedly connected to a main cable located above the driving mechanism, and the other end of which is provided with a limiting mechanism connected to the first traction rope for locking or unlocking the first traction rope.

[0050] In an exemplary structure, the limiting mechanism includes a clamping sleeve, the first traction rope passes through the clamping sleeve, and the first traction rope is provided with a clamping head that is clamped and connected to the clamping sleeve. When the clamping sleeve is clamped with the clamping head, the retraction and extension of the first traction rope are restricted.

[0051] In a more preferred solution, the driving mechanism is further provided with an energy storage module, which converts the kinetic energy generated when the first traction rope is released into electrical energy, at least for replenishing electrical energy for the driving mechanism.

[0052] Application Examples

[0053] This application example is combined with a complete side-mounted high-altitude wind energy system to further clearly describe the structure and working process of the driving device in the above embodiment.

[0054] Figure 1The main components of the side-mounted high-altitude wind energy system are shown, including a main cable 200, one end of which is connected to the aerial guide and balance module 100, and the other end is connected to the ground device. A working parachute 300 is set on the main cable 200, and the opening and closing of the working parachute 300 is controlled by the driving device in the above embodiment. In addition, reference can be made to any existing high-altitude wind energy system. The ground device in this application example is equipped with a control unit for controlling the aerial module. The aerial module also includes necessary posture and environmental sensor modules, wireless signal transceiver systems, wind energy and / or solar energy storage modules, etc. These devices are fixedly mounted on the main cable 200 near the driving mechanism 600 and will not be described in detail here.

[0055] During the initial launch phase, the aerial guidance and balance module 100 provides a certain amount of lift. This lift, by pulling on the main cable 200, leads all the aerial modules mounted on it to a preset altitude. During the parachute 300's wind-catching phase, the aerial guidance and balance module 100 also adjusts and maintains a suitable angle of attack for the aerial system, thereby optimizing its power output.

[0056] Specifically, the sliding mechanism 900 is mounted on the main cable 200 and can slide freely up and down the main cable 200. The parachute 300 has a fixed point around its circumference, which can be directly connected to the sliding mechanism 900. Alternatively, a cable of suitable length can be used to connect the sliding mechanism 900 and the fixed point around the parachute 300, as needed. When the parachute ascends or descends, the fixed point around its circumference drives the sliding mechanism 900 to slide synchronously up and down along the main cable 200. To ensure smooth operation during calm winds or during the initial ascent, a stopper 800 is positioned on the main cable 200 to limit the downward movement of the sliding mechanism 900.

[0057] A number of circumferential parachute lines 310 are evenly connected around the working parachute 300, and the ends of the circumferential parachute lines 310 are evenly attached to the first convergence mechanism 320. One end of the first traction rope 500 is connected to the first convergence mechanism 320, and the other end is connected to the retracting and releasing rope mechanism (such as a small winch module) of the driving mechanism 600 fixedly installed on the main cable 200. A transfer rope 700 of a suitable length is also installed on the main cable 200 at an appropriate position above the driving mechanism 600, and a ferrule 710 is installed on the other end of the transfer rope 700. The first traction rope 500 passes through the ferrule 710, and a clamp head 510 is also fixedly installed on the first traction rope 500. The clamp head 510 and the ferrule 710 form a clamping mechanism, and the two can be locked or disconnected in a controlled manner.

[0058] Several top parachute cords (not shown) are evenly attached around the top opening of the power parachute 300. The other ends of the top parachute cords are attached to a second convergence mechanism (not shown, but identical in structure and function to the first convergence mechanism 320). A second traction cord 400 has one end connected to the second convergence mechanism, positioned in the center of the parachute top, and the other end connected to the retraction and release mechanism of the drive mechanism 600. The retraction and release mechanism connecting the second traction cord 400 and the retraction and release mechanism connecting the first traction cord 500 in the drive mechanism 600 are configured to independently or synchronously control the retraction and release of the second traction cord 400 and the first traction cord 500.

[0059] During the initial lift-off phase of the parachute 300, the fixed point and the sliding mechanism 900 on the parachute 300 are restricted to the position of the stopper 800, and the parachute 300 appears to be suspended. Figure 2 As the altitude rises and the wind becomes stronger, the working parachute 300 will be blown open by the wind, and the fixed points around the parachute will take the sliding mechanism 900 away from the position of the block 800 and move upward together until the parachute is fully unfolded by the wind, presenting Figure 1 The effect of the umbrella opening is shown.

[0060] When the power parachute is in the open state, the clamp 510 of the first traction rope 500 and the clamping sleeve 710 on the transfer rope 700 are in a locked connection state, such as Figure 1 As shown. The wind force captured by the power parachute 300 is transmitted to the first convergence mechanism 320 via the parachute's circumferential parachute lines 310, and then to the clamp and device consisting of the clamp head 510 and the clamp sleeve 710. This is then transmitted to the main cable 200 via the transmission line 700. The main cable 200 then pulls the ground module to generate power or electricity. In this application example, by side-mounting the power parachute 300 on the main cable 200, the power parachute 300 is completely prevented from rotating due to uneven airflow. Therefore, line entanglement and entanglement between the lines and the first and second traction lines 500 and 400 are prevented.

[0061] When the aerial working module runs to the preset upper limit altitude, the working system switches to the parachute closing mode. After the parachute closing command is issued, the driving mechanism 600 first locks the second traction rope 400, and at the same time switches the first traction rope 500 to the rope releasing mode, and then unlocks the connection between the clamp head 510 and the clamping sleeve 710. The top of the working parachute 300 will quickly fold upwards because it is restrained by the second traction rope 400 and loses the restraint of the parachute rope 310 around the umbrella. In particular, since the fixed point on the working parachute 300 is connected to the sliding mechanism 900, the sliding mechanism 900 will slide upwards along the main cable 200 during the process of the working parachute 300 folding upwards. The state diagram at the moment the parachute is closed is as follows. Figure 3 shown.

[0062] After the parachute is closed, the system switches to reset mode. In reset mode, since the active parachute 300 is in its folded position and cannot properly catch wind, the ground-based system only consumes a small amount of energy to pull the aerial system back to the preset lower altitude limit. Simultaneously, the drive mechanism 600 simultaneously retracts the first and second traction ropes 500 and 400, while maintaining the active parachute 300 in its folded position. The clamping head 510 is then reconnected to the clamping sleeve 710 and locked. This completes reset mode. Figure 4 The figure shows the reset mode completion status.

[0063] When the air system returns to the preset lower altitude limit and completes the reset, the system will switch to the parachute opening mode again (refer to Figure 5 ). After the parachute opening command is issued, the driving mechanism 600 stops retrieving the second traction rope 400, but continues to retrieving the first traction rope 500. Since the transfer rope 700 has a certain length, the driving mechanism 600 can theoretically pull back the transfer rope 700 by a distance of about twice. At this time, the parachute 300 will be folded back from the folded state and quickly take off and bear the force. Furthermore, the top of the parachute 300 also begins to be subjected to force to pull back the second traction rope 400. When the driving mechanism 600 detects the tension on the top of the parachute 400, it stops retrieving the first traction rope 500 and simultaneously releases the first traction rope 500 and the second traction rope 400. As the power parachute 300 continues to take off and bear the force and the first traction rope 500 is further released, the force on the parachute ropes 310 will quickly be transferred to the transfer rope 700 through the card and mechanism. At this time, the driving mechanism 600 stops releasing the first traction rope 500. As the parachute 300 is deployed, the second traction rope 400 is also released. The drive mechanism 600 then stops releasing the second traction rope 400, but maintains a suitable tension on the second traction rope 400 to prevent it from becoming entangled with the parachute lines. The parachute deployment process is now complete.

[0064] Compared with the traditional mode in which the main cable 200 passes through the center of the power parachute, the mode in which the power parachute 300 is hung sideways on the main cable has a lower windward angle, and the state of the parachute surface can be adjusted by controlling the relative positions of the first traction rope 500 and the second traction rope 400, making it easier to open the power parachute 300 and the wind speed at which it cuts in is also lower.

[0065] In a preferred embodiment, during the closing process of the parachute, the driving mechanism 600 can also be synchronously switched to a power generation mode, converting the kinetic energy generated when the first traction rope 500 is released into electrical energy to supplement the endurance power of electrical equipment such as the driving mechanism 600.

[0066] In a more preferred solution, multiple side-mounted active parachutes 300 and corresponding drive devices can be installed on the main cable 200 as needed to form a side-mounted parachute ladder system, which can multiply the system output power. In actual application, some active parachutes in the parachute ladder can be flexibly opened or closed according to wind speed and power output requirements to achieve stable and adjustable output power. Figure 6 In addition, compared with the main cable through the scheme, the side-mounted parachute ladder is more flexible and easier to install and maintain.

[0067] The embodiments and application examples described above are merely illustrative descriptions of the present disclosure and do not limit the scope of the present disclosure. Without departing from the design spirit of the present disclosure, various modifications and improvements made to the technical solutions of the present disclosure by ordinary technicians in this field should fall within the protection scope determined by the present disclosure.

Claims

1. A side-mounted high-altitude wind energy drive device, characterized in that: It includes a sliding mechanism and a driving mechanism respectively connected to a working parachute; The sliding mechanism is configured to slide freely along the main cable and is connected to the parachute of the power-producing parachute, so as to achieve synchronous sliding along the main cable with the power-producing parachute; The driving mechanism is fixedly arranged on the main cable located below the sliding mechanism and is connected to a plurality of parachute lines arranged around the working parachute, and is used for pulling the parachute lines. The top of the working parachute is connected to the driving mechanism via a traction rope, and the driving mechanism controls the retraction and extension of the traction rope.

2. The driving device according to claim 1, characterized in that The parachute ropes around the umbrella converge and connect to the first traction rope, and the driving mechanism is connected to the first traction rope and controls the retraction and extension of the first traction rope; The umbrella top is evenly provided with a plurality of umbrella top parachute ropes, and the umbrella top parachute ropes converge and are connected to the second traction rope. The driving mechanism is connected to the second traction rope and controls the retraction and extension of the second traction rope.

3. The driving device according to claim 2, characterized in that The driving mechanism controls the retraction and extension of the first traction rope and the second traction rope simultaneously or separately.

4. The driving device according to claim 2, characterized in that including a first converging mechanism and a second converging mechanism; The parachute lines around the umbrella are connected to the first converging mechanism, and the first converging mechanism is connected to the first traction rope; the parachute lines at the top of the umbrella are connected to the second converging mechanism, and the second converging mechanism is connected to the second traction rope.

5. The driving device according to claim 2, characterized in that It also includes a transfer rope, one end of which is fixedly connected to the main cable located above the driving mechanism, and the other end of which is provided with a limiting mechanism; The limiting mechanism is connected to the first traction rope and is used to lock the first traction rope or unlock the first traction rope.

6. The driving device according to claim 5, characterized in that The limiting mechanism includes a clamping sleeve, the first traction rope passes through the clamping sleeve, and the first traction rope is provided with a clamping head that is clamped and connected to the clamping sleeve.

7. The driving device according to claim 1, characterized in that It also includes a stopper provided on the main cable, and the stopper is used to limit the range of the sliding mechanism sliding downward along the main cable.

8. The driving device according to claim 1, characterized in that The umbrella circumference of the working parachute is directly connected to the sliding mechanism; or The umbrella circumference of the working parachute is connected to the sliding mechanism via a section of cable.

9. The driving device according to claim 2, characterized in that The driving mechanism is provided with an energy storage module, which converts the kinetic energy generated when the first traction rope is released into electrical energy, at least for replenishing electrical energy for the driving mechanism.

10. A side-mounted high-altitude wind energy system, characterized in that: It comprises a main cable and at least one working parachute, one end of the main cable is connected to an aerial guide balance module and the other end is connected to a ground module, and the working parachute uses the driving device according to any one of claims 1 to 9.

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