47 results about "Tension-leg platform" patented technology

The invention discloses a tension leg type offshore wind power platform and a tendon dynamic balance adjusting method.The wind power platform comprises a center stand column, side buoys, a floating bridge and tendons, a plurality of ballast tanks are arranged in the floating bridge and the side buoys, and a plurality of emergency water inlets are formed in the bottom of the floating bridge and the tops and the bottoms of the side buoys; a ballast tank communicating opening which can be selectively communicated with the buoy ballast tank is formed in the lower part of the floating bridge ballast tank close to the buoy; and a ballast system is arranged in each ballast tank, and the ballast systems can be used for carrying out pressure discharge on the ballast tanks or selectively transferring water in any ballast tank to other ballast tanks. The internal ballast can be selectively adjusted through a natural flowing mode and / or a mechanical mode based on the tendon tension, the tendon failure position and the tendon failure number can be judged, an emergency control strategy is formulated according to the tendon failure condition, the service life of a mooring system is prolonged, and the safety of the mooring system is improved. And the self-storage performance of the tension leg platform can be improved when the mooring system breaks down.

The invention discloses a TLP tension tendon supporting device and a tension leg platform, the TLP tension tendon supporting device comprises an assembly locking mechanism, a split structure and a mooring anchoring mechanism which are sequentially connected from top to bottom, the split structure comprises a top deck, an outer bulkhead, a first bulkhead, a bottom deck and a central pipe, and the top deck, the bottom deck and the outer bulkhead define a shell; the center pipe is arranged in the middle of the split structure in the middle, and the multiple first bulkheads are distributed between the outer bulkhead and the center pipe in the radial direction of the center pipe. The mooring anchoring mechanism comprises a top universal joint shackle, a top anchor chain section, a mooring rope, a bottom anchor chain section, a bottom shackle and a seabed anchor pile which are sequentially connected from top to bottom. The tension tendon system can be prevented from being directly installed on the floating body foundation, the design and construction of the fan floating body are not affected by the tension tendon, the displacement of the floating body can be increased, the size of the floating body can be reduced, on one hand, the heaving damping of the floating body is increased, the heaving motion response is reduced, and on the other hand, the construction, installation, operation and maintenance cost of the floating body is reduced.

The invention provides a deep sea floating type wind power tension leg platform mooring device which comprises a top connector, a steel cable and a bottom connector, the top connector comprises a clamping device, a middle column, a supporting device and a support structure, the interior of the clamping device is connected with the upper portion of the middle column in a locking mode, the lower portion of the clamping device is connected with the supporting device, the supporting device is connected with the support structure, and the steel cable is connected with the bottom connector. The support structure is connected to the tension leg platform. The top of the middle column is connected with the installation cable, the bottom of the middle column is connected with one side of the steel cable, the other side of the steel cable is connected with the bottom connector, and the bottom connector is connected with the seabed anchoring part. The device is simple in structure and light in weight, meets the use requirements of platform mooring, and has the characteristics of low cost and easiness in batch production.

The invention discloses a cable stopper device for adjusting mooring tension, and relates to the technical field of offshore mooring, the cable stopper device comprises a shell fixed on a tension leg platform, the upper end and the lower end of the shell are both provided with openings, the inner wall surface of the shell is an inner concave cambered surface, the inner side of the shell is slidably connected with a head stopper, the head stopper is of a split structure, and the head stopper is provided with an opening. A through hole is formed in the middle of the head stopper, a dragging head is arranged in the through hole in a penetrating mode, clamping teeth are arranged on the outer wall of the dragging head and the hole wall of the through hole, and the dragging head is matched with the head stopper in a limiting mode through the clamping teeth. Connecting rings are arranged at the two ends of the dragging head, the top end of the dragging head is connected with a winch cable on the tension leg platform, and the bottom end of the dragging head is connected with a mooring cable connector on the tension leg platform. The clamping teeth on the dragging head and the clamping teeth on the head stopper are all involute tooth profiles, the head stopper is in an open state when the dragging head is pulled upwards, the head stopper and the dragging head can be locked and stopped in a closed state, and therefore the tension can be adjusted in the field operation period of the tension leg platform.

The invention discloses a folding type tension leg floating platform which comprises a central tower column, an umbrella-shaped floating body and a locking component, and the umbrella-shaped floating body and the locking component are arranged on the central tower column; a central ballast tank is arranged on the central tower column, and a bearing part is arranged above the central ballast tank; the umbrella-shaped floating body comprises a plurality of buoys and sliding pieces, one ends of the buoys are movably connected with the central tower column through the sliding pieces, the buoys can be unfolded or folded relative to the central tower column, when the buoys are unfolded, the other ends of the buoys are connected with the tension tendons, and the buoys are supported on the bearing parts; the locking component is arranged above the buoy, and in the locking state, the locking component can abut against the buoy in the unfolded state to the bearing part. According to the invention, not only is the transportation convenience of the tension leg platform, especially the tension leg platform with a cantilever type buoy improved, but also the problem of structural stress overrun at a connecting node when a floating body structure is in a working state can be effectively avoided.

The invention belongs to the field of offshore wind power, and discloses an automatic suction barrel mounting device for offshore wind power construction and a tension leg platform mounting method.The automatic suction barrel mounting device comprises a storage mechanism, a grabbing mechanism and a rotary moving mechanism, the storage mechanism stores a plurality of suction barrels at intervals in an annular mode, the grabbing mechanism grabs the suction barrels, and the rotary moving mechanism rotates to move the suction barrels; the rotary moving mechanism drives the grabbing mechanism to move and rotate, so that the grabbing mechanism can grab the suction barrels on the storage mechanism to the anchoring positions corresponding to the seabed one by one. According to the automatic mounting device for the suction barrel, mounting of the suction barrel is simplified through mechanical and automatic processes, and efficiency is improved.

The invention provides a mooring device for a tension leg platform pool test and a test method. The device comprises a first mooring rope, an extension spring and a second mooring rope which are connected in sequence, and the second mooring rope is connected with a tensioning mechanism; the specification of the cable meets the conditions that A is the sectional area of the cable, k is the safety coefficient, Tmax is the maximum expected tension, sigmaallow is the allowable stress of a cable material, d is the diameter of the cable, L is the effective stress length of the cable, R is a judgment threshold value, Ks is the rigidity of an extension spring, E is the elastic modulus of the cable material, and model selection is conducted on the cable according to the target tension force range; the system equivalent stiffness Ktot in the test is ensured to be dominated by the extension spring, the contribution of the cable stiffness to deformation can be ignored, and the accuracy of equivalent stiffness control of the pool test and the repeatability of the test are improved.

The present invention discloses an anchor-type split assembly type anchor foundation and a tension leg platform, wherein the tension leg platform comprises a pile foundation, the pile foundation comprises a first base and a second base connected to each other, the first base is used to be inserted into the ground, and the second base is set as a hollow structure, and the anchor-type split assembly type anchor foundation also comprises an anchor device, the anchor device is sleeved on the outer wall of the second base, and the inner wall of the anchor device is provided with a shear key. The anchor-type split assembly type anchor foundation utilizes the first base to be driven into the soil, and then the second base is set as a hollow structure, and the reinforcement performed by the anchor device can greatly improve the overall stiffness and strength of the single pile foundation, improve the whole machine frequency of the wind turbine, improve the comprehensive bearing performance of the wind turbine foundation, and make the large-diameter single pile suitable for deeper water depths and more complex marine environments. In addition, by arranging shear keys on the inner wall of the anchor device, the ability of the deep-water floating wind power platform to resist environmental loads is further improved.

The invention discloses a tension leg buoy type single-point mooring system which comprises a mooring column module, a buoy module and a buoy module. The mooring column module is used for being connected with a ship. The buoy device is used for stably floating on the sea surface, so that the ship is moored at a single point; the tying column module is arranged in the middle of the top of the buoy device; the acceleration folding and unfolding device is used for adjusting the floating state of the buoy and floats on the sea surface or sinks under the sea bottom; the tension leg platform is used for supporting the buoy device and is arranged under the buoy device; and the fixing module is used for fixing the quick tightening device and the tension leg platform. The device realizes instant switching of the states of the buoys, effectively prolongs the service life of the system, and shows excellent performance and adaptability. A tension leg system and an adjustable floating state buoy structure are combined, an acceleration retracting and releasing device is arranged, and the acceleration retracting and releasing system can retract the buoy under the sea surface when a severe environment comes, so that the safety of the whole single-point mooring system is improved, and the service life of the single-point mooring system is prolonged.

The invention discloses a low-friction implementation method for simulating the dynamic installation process of a tension leg platform, and the method comprises the steps: connecting a floating platform, a tower cylinder and a floating cylinder to form a platform main body structure, and arranging a deck lifting point at one side, facing the floating cylinder, of the floating platform, the deck lifting point is connected with a steel wire rope; the anchoring device is used for leading out one end of the steel wire rope away from the deck lifting point through a fairlead arranged on the buoy and fixing to the bottom of the pool; the cable guide hole is provided with a circular ring guide piece, and the steel wire rope penetrates through the circular ring guide piece so as to avoid clamping stagnation or sudden sliding of the steel wire rope in the dynamic loading process. According to the low-friction implementation method for simulating the dynamic installation process of the tension leg platform, the guide function of the steel wire rope and the structure of the floating body of the platform are functionally decoupled through the design of the ring guide piece with the separated structure, path adjustment, configuration change and parameter iteration can be conveniently carried out in the test process, and it is guaranteed that the steel wire rope is evenly stressed in the sliding process.

According to the marine transportation tool of the tension leg platform, the marine transportation tool of the tension leg platform is improved, and the stability of the tension leg platform in the wet dragging transportation process is guaranteed. The tension leg platform comprises a mounting column and a tension arm, the tension arm comprises an arm body connected with the mounting column and a wrist part protruding from the arm body, the marine transportation tool comprises a plurality of floating bodies, and a plurality of ballast tanks are arranged in the floating bodies and used for injecting or discharging ballast water; every two floating bodies form a group and are connected with the wrist parts of the corresponding tension arms, and the two floating bodies belonging to the same group are respectively arranged on the two sides of the tension arms.

The application provides a small star-shaped tension leg platform installation method, which comprises the following steps: S1, transporting a lower floating body to a work sea area and connecting the lower floating body with a suction anchor pre-installed on a seabed; the lower floating body is submerged to a preset depth and balanced; S2, dry towing an upper floating body to the work sea area; connecting the upper floating body and a towing boat through a temporary mooring cable; inflating an air bag to make the upper floating body float on the water surface; S3, slowly floating the lower floating body and aligning a first sleeve, a second sleeve and a third sleeve on the upper floating body with a first guide pile, a second guide pile and a third guide pile on the lower floating body in sequence, slowly transferring the weight of the upper floating body to the lower floating body until the air bag is completely floated out of the water surface; S4, tensioning an anchor chain, discharging the gas in the air bag and completing the installation; in the whole installation process, a large floating crane is not needed, the installation cost is reduced, the docking difficulty is effectively reduced and the docking efficiency is improved by adopting the way of sequentially docking and positioning the guide piles and the sleeves.

A tension leg platform assembly is provided, comprising a buoyant body and a number of mooring assemblies attached thereto, which extend between the buoyant body and a fixed foundation on the seabed. Each mooring assembly comprises at least one elongate member having an upper end and an opposite lower end. At least one of said upper end and lower end by means of a connector assembly is connected to the buoyant body or the fixed foundation, respectively. Said connector assembly is provided with a first yoke which is connected to the buoyant body or fixed foundation for a rotation around a first axis which extends substantially horizontally at a first level, and a second yoke attached to the elongate member which is mounted in the first yoke for a rotation around a second axis which extends substantially perpendicularly to the first axis at a second level. The second level is further away from the upper end or lower end, respectively, of the elongate member than the first level.

The invention provides an offshore wind power device and an installation method of the offshore wind power device. The defects in the process of assembling the offshore wind power device on the land are overcome. The offshore wind power device comprises a tension leg platform and a fan, the tension leg platform comprises a mounting column and a tension arm, the mounting column is used for being connected with the fan, and the tension arm comprises an arm body connected with the mounting column and a wrist protruding from the arm body; the tension leg platform is provided with a marine transportation tool, the marine transportation tool comprises a plurality of floating bodies, the floating bodies are connected to the wrist part, and a plurality of ballast tanks are arranged in the floating bodies and used for injecting or discharging ballast water; the installation method comprises the steps that s1, the tension leg platform and the draught fan are towed to an assembly water area; s2, ballast water is injected into the floating body until the tension leg platform sits at the bottom; s3, the fan and the tension leg platform are assembled; s4, discharging ballast water in the floating body; and s5, towing the assembled fan and tension leg platform to an installation water area, and connecting the tension leg platform with the seabed of the installation water area.

The application discloses a kind of marine drilling dry wellhead blowout preventer tensioner, including two tensioning liquid cylinders, chain and energy storage control pry, each tensioning liquid cylinder is connected with blowout preventer group hanging by chain, two tensioning liquid cylinders are communicated with the high-pressure outlet of energy storage control pry by a high-pressure hose respectively, two tensioning liquid cylinders are also communicated with the low-pressure return port of energy storage control pry by a low-pressure hose respectively.The device of the application meets the top tension requirement of blowout preventer for offshore jack-up drilling platform and tension leg platform, and also has high integration degree, good stability, good practicality and popularization value.

The present invention discloses an offshore wind turbine coupled energy storage double floating system, including a tension leg platform and a wind turbine, the wind turbine is installed on the floating base of the tension leg platform; a hydrogen energy storage device is arranged on the tension leg platform, the hydrogen energy storage device can convert electrical energy into hydrogen energy to store and release the wind power generated by the wind turbine; the hydrogen energy storage device is a suspension, and the suspended hydrogen energy storage device is flexibly connected to the floating base; the wind turbine and the hydrogen energy storage device are limitedly matched, the wind turbine produces horizontal constraints on the hydrogen energy storage device, and the flexible connection between the floating base and the hydrogen energy storage device produces vertical constraints on the hydrogen energy storage device; the wind turbine has a vertical tower, and a limited hole is formed on the hydrogen energy storage device; the tower is correspondingly located in the limited hole to produce horizontal constraints on the hydrogen energy storage device; the floating base is connected to the hydrogen energy storage device through a rope body to produce vertical constraints on the hydrogen energy storage device. The present invention can effectively solve the problem of wind abandonment and power restriction of offshore wind power in deep sea areas and improve the utilization rate of wind energy.

The present invention belongs to the field of offshore wind power, and discloses an automatic installation device for suction buckets used in offshore wind power construction and an installation method for a tension leg platform, including a storage mechanism, a grasping mechanism, and a rotating and moving mechanism. The storage mechanism stores a plurality of suction buckets at annular intervals. The grasping mechanism grasps the suction buckets, and the rotating and moving mechanism drives the grasping mechanism to move and rotate, so that the grasping mechanism can successively grasp the suction buckets on the storage mechanism to the corresponding anchoring positions on the seabed. The present invention proposes an automatic installation device for suction buckets, which simplifies the installation of suction buckets through mechanized and automated processes and improves efficiency.

The utility model discloses a TLP tension tendon supporting device and tension leg platform, it includes from top to bottom assembly locking mechanism, split structure, mooring anchoring mechanism, split structure includes top deck, outer bulkhead, first bulkhead, bottom deck, central tube, top deck, bottom deck and outer bulkhead enclose the shell, and the outer bulkhead is equipped with the outer bulkhead. The center pipe is arranged in the middle of the split structure in the middle, and the multiple first bulkheads are distributed between the outer bulkhead and the center pipe in the radial direction of the center pipe. The mooring anchoring mechanism comprises a top universal joint shackle, a top anchor chain section, a mooring rope, a bottom anchor chain section, a bottom shackle and a seabed anchor pile which are sequentially connected from top to bottom. The tension tendon system can be prevented from being directly installed on the floating body foundation, the design and construction of the fan floating body are not affected by the tension tendon, the displacement of the floating body can be increased, the size of the floating body can be reduced, on one hand, the heaving damping of the floating body is increased, the heaving motion response is reduced, and on the other hand, the construction, installation, operation and maintenance cost of the floating body is reduced.

The present invention discloses a tensegrity marine platform for offshore wind power generation, including tension legs, platform cables, bottom transverse cables, movable platforms, oblique cables, arc-shaped support pipes, central columns, connection nodes, radial cables, top transverse cables, top support rods, top oblique cables and transverse reinforcement cables; its external main frame includes four arc-shaped support pipes, oblique cables connecting the top node with the bottom node of the adjacent rod, and top transverse cables and bottom transverse cables connecting the top and bottom nodes of two adjacent rods respectively; the internal movable platform is connected to the external main frame through the platform cables, and part of the platform's remaining buoyancy is consumed to tighten it and form a tensioning structure. The present invention applies the tensegrity structure to the marine platform, and through a special tensioning structure, the vibration of part of the main tensegrity structure and the movable platform is offset, so that the platform is more stable when encountering wind and waves, and the problem that the traditional tension leg platform is easy to resonate with the wave frequency is improved.

Tension-leg platforms for supporting wind turbines are augmented with surge plates. The surge plates increase the amount of water that is displaced when a tension-leg platform is accelerated horizontally, which reduces wave induced accelerations. The surge plates are mounted to the deepest parts of the submerged structure of each platform to minimize wave loading.

The utility model belongs to the field of offshore wind power, and discloses a tension leg platform system with a tendon balancing device, which comprises a tension leg platform, a plurality of tendons are annularly distributed on the periphery of the lower end of the tension leg platform, and the lower ends of the tendons are connected with a suction cylinder, and is characterized in that the tension leg platform is connected with the tendons through the tendon balancing device; the tendon balancing device comprises a telescopic assembly and a driving assembly, the telescopic assembly comprises a telescopic fixed part and a telescopic movable part which are in telescopic sliding fit, the telescopic fixed part is connected with the tension leg platform, the telescopic movable part is connected with the tendon, and the driving assembly drives the telescopic movable part to stretch out and draw back relative to the telescopic fixed part. According to the tension leg platform, the stress of the tendons is dynamically adjusted through the tendon balancing device, the stress state of the platform is adjusted in real time, and the problem of inclination and vibration caused by environmental factors such as wind waves and flow is solved.

This invention discloses a modular offshore wind turbine tension leg foundation structure and its construction method, aiming to provide a modular offshore wind turbine tension leg foundation structure and its construction method that can effectively reduce the cost of offshore wind power projects and the installation risk of tension leg foundation structures, while effectively shortening the construction time. A modular offshore wind turbine tension leg foundation structure includes: a platform body, including a central column and several buoys evenly distributed around the central column, the central column and each buoy being connected as a whole by a support; a suction cylinder foundation module, including several suction cylinders, each suction cylinder being connected as a whole by a connecting beam; a tension leg mooring module, including several mooring devices, each mooring device including a mooring cable and a mooring cable deployment and retrieval device located on the platform body, the lower end of the mooring cable being connected to the suction cylinder foundation module; the mooring cable deployment and retrieval device can release the mooring cable, allowing the suction cylinder foundation module to separate from the platform body and be lowered to the seabed.

The invention provides a large-stroke rapid-lifting composite tendon tension leg platform and a construction method thereof, and aims to solve the technical problems that an existing floating platform is poor in stability, high in tendon tensioning difficulty and low in efficiency. Comprising a floating type frame and a gravity anchor, and the floating type frame comprises an elevated platform and a deep diving floating body; the elevated platform is connected with the gravity anchor through a plurality of first tension tendons, and the first tension tendons are used for adjusting the submerging depth of the floating type frame in water; and the deep diving floating body is connected with the gravity anchor through a plurality of second tension tendons. The composite tendon tension leg platform can rapidly tension the tension tendon, the height of the platform away from water can be adjusted according to needs, and the composite tendon tension leg platform is high in stability, easy to construct and suitable for various scenes.

The invention discloses a tension leg platform tension tendon real-time tension measuring device which comprises a rocker arm, a first shackle and a second shackle, the first shackle and the second shackle are connected to the two ends of the rocker arm respectively, the first shackle is connected to a platform, the second shackle is connected to a tension tendon, and the first shackle and the second shackle are connected to the rocker arm. The rocker arm is arranged between the platform and the tension tendon; the rocker arm is connected with a first fixing block and a second fixing block, a tension adjusting arm is connected between the first fixing block and the second fixing block through a connecting rod, and the tension adjusting arm is connected with an optical fiber force transducer, so that when the rocker arm slightly deforms, the tension adjusting arm deforms synchronously, and the optical fiber force transducer outputs a signal through a cable. Therefore, the tension value of the tension tendon is obtained. The real-time tension measuring device for the tension tendon of the tension leg platform is provided with two sets of measuring systems for respective measurement and mutual verification, and meanwhile, the real-time tension measuring device is simple in structure and convenient to operate, maintain and replace.

This invention discloses a tension leg offshore wind turbine platform and a dynamic balance adjustment method for its tendons. The wind turbine platform includes a central column, side buoys, a floating bridge, and tendons. Multiple ballast tanks are located inside both the floating bridge and the side buoys. Multiple emergency water inlets are located at the bottom of the floating bridge and the top and bottom of the side buoys. A ballast tank connection port, selectively connecting to the ballast tanks of the floating bridge, is located at the lower part of the ballast tank near the buoy. A ballast system is installed inside each ballast tank, which can perform ballast discharge or selectively transfer water from one ballast tank to another. This invention can selectively adjust the internal ballast based on tendon tension through natural flow and / or mechanical means. It can determine the location and number of tendon failures and formulate emergency control strategies based on the tendon failure status. This not only improves the lifespan of the mooring system but also enhances the self-survival performance of the tension leg platform under mooring system failure.

This invention provides a gravity-based multi-tension-leg floating wind turbine platform, comprising: a wind turbine and its tower, a buoyancy chamber, a tensioning mooring system, and a gravity foundation. The wind turbine and its tower are mounted on top of the buoyancy chamber; the buoyancy chamber is connected to the gravity foundation arranged on the seabed via the tensioning mooring system to form a tension leg restraint system. The tensioning mooring system, by significantly increasing the number and rationally distributing the cables, distributes the platform's tension under the influence of wind, waves, and currents among more tensioning components, thereby reducing the tensile force and fatigue load requirements of a single tensioning mooring member and its end connecting components, and reducing the engineering implementation difficulty caused by excessive stress on the tension legs. The gravity foundation is fixed to the seabed by its own weight, eliminating the need for piling operations required for traditional tension-leg platforms, significantly reducing the difficulty and cost of offshore construction.

The utility model discloses a tension leg type wind wave coupling power generation foundation which comprises a stand column used for installing a wind turbine generator and a fan tower drum, the stand column is fixed to a frame, a buoy is fixed to the bottom of the frame and is moored through tension tendons, the tension leg type wind wave coupling power generation foundation comprises an oscillating floater, and a pulling rope is arranged on the buoy to pull the oscillating floater. A winch, a generator, a storage battery and a motor are arranged in the buoy, the lower end of the traction rope is wound around the winch, the generator and the motor are in transmission connection with the winch, and the storage battery is electrically connected with the generator and the motor. The problem that an offshore power generation platform adopting a floating structure to capture wave energy transmits an overhigh load to the power generation platform under an extreme sea condition to affect safety is solved.

A floating structure (1) for transporting and installing a floating tension leg platform (TLP) (2) having a plurality of legs (3) radiating from a central point (4) is provided. The floating structure comprises: controllable ballast tanks (6, 6 ') for changing the buoyancy of the floating structure; and engagement means (9) engaged with the legs (3) of the TLP and maintaining the legs (3) at the desired draft during transportation and installation. The floating structure comprises a plurality of floating structure portions intended to be positioned horizontally near each leg of the TLP and provided with engagement means (9), in such a way as to engage mating engagement means provided on the legs of the TLP, such that in an operational position of the floating structure in which the floating structure portions are positioned horizontally alongside the legs of the TLP, the engagement means (9) engage mating engagement means provided on the legs of the TLP. The engagement means can be loaded on the mating engagement means with a downward force opposite the upward buoyancy of the TLP, and the engagement means are further arranged such that the engagement means can be engaged with the mating engagement means in the above-mentioned manner even when the legs of the TLP are at least partially located at a height above the sea level.

To provide a floating body structure for transportation and installation of a floating body type tension leg platform.SOLUTION: A floating body structure 1 includes controllable ballast tanks 6, 6' for varying its buoyancy and engaging means 9 engaging with leg unit 3 for maintaining necessary draft during transportation and installation. The floating structure includes a multiple number of floating structure parts intended to be positioned adjacent horizontally to each leg unit, the floating structure part includes the engaging means 9 for engaging with a means to be engaged provided on the leg unit, and thus, the engaging means is capable of loading the means to be engaged with downward force against the floating upward force in an action attitude of the floating body structure positioned horizontally lined up with the leg unit, and furthermore, the engaging means is installed to be capable of engaging with the means to be engaged even when one portion of the leg unit is positioned at a height above the sea level.SELECTED DRAWING: Figure 2