A two-way light supply device for plant factory leaf surface

Abstract

The application discloses a kind of plant factory leaf two-way light supply device, including cultivation board, top plate being arranged above cultivation board and cultivation hole being arranged at the top of cultivation board, and the bottom ring-shaped lamp strip of multiple groups is arranged in annular array along cultivation hole at the top of cultivation board, top ring-shaped lamp strip is arranged on the outer wall of top plate by connecting piece, and bottom ring-shaped lamp strip and top ring-shaped lamp strip are rotated along the central axis direction of them by driving mechanism, and top ring-shaped lamp strip bottom is also provided with spray head;The bottom ring-shaped lamp strip is arranged along the cultivation hole at the top of cultivation board in the application, and top ring-shaped lamp strip is arranged on the top plate by connecting piece, so that the top and bottom leaf surface of plant can be illuminated simultaneously, effectively solve the problem that the lower part and bottom leaf of plant are insufficiently illuminated due to single top light source, promote the overall photosynthesis of plant, and improve the consistency of light energy utilization and plant growth.

Description

Technical Field

[0001] This invention relates to the field of agricultural planting technology, to plant factories, and more particularly to a bidirectional light supply device for the leaf surface of a plant factory. Background Technology

[0002] In plant factories and artificial light environment cultivation systems, light is a key environmental factor regulating plant photosynthesis, morphogenesis, and growth and development. Currently, existing technologies generally use top light sources for unidirectional supplemental lighting of plants, that is, placing lighting devices only above the plant canopy to simulate the downward illumination of sunlight. This type of top lighting solution can meet the basic needs of plant growth to a certain extent, but it still has the following shortcomings: First, top-mounted light sources cannot evenly cover the lower and middle parts of the plant and the bottom leaves, resulting in insufficient light in the area below the plant canopy, which affects the overall photosynthetic efficiency. This is especially true for tall plants or densely planted cultivation scenarios, where the bottom leaves are prone to yellowing and premature aging. Second, fixed top-mounted light sources cannot dynamically adjust the angle and area of ​​illumination, making it difficult to simulate the continuous changes in the direction of light in nature over time. If the light source is frequently switched on and off to simulate the changes in light and darkness in nature, it will easily lead to a shortened lifespan of the lamps and increase equipment maintenance costs. Summary of the Invention

[0003] The purpose of this invention is to solve the problems in the prior art by proposing a bidirectional light supply device for the leaf surface of a plant factory.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A two-way light supply device for plant factory leaves includes a cultivation board, a top plate disposed above the cultivation board, and cultivation holes disposed on the top of the cultivation board. The top of the cultivation board is provided with multiple sets of bottom annular light strips arranged in a circular array along the cultivation holes for providing light to the bottom of the plants. The outer wall of the top plate is provided with a top annular light strip for providing light to the top of the plants via a connector. Both the bottom and top annular light strips are rotated along their central axis by a drive mechanism. A spray head is also provided at the bottom of the top annular light strip.

[0005] As a preferred technical solution of this application, both the bottom annular light strip and the top annular light strip include an annular light frame and a supplementary light embedded inside the annular light frame.

[0006] As a preferred technical solution of this application, the arc length of the supplementary light distributed on the annular light strip corresponds to a central angle of 90 degrees; in the vertical projection direction, each top annular light strip has four bottom annular light strips distributed up, down, left, and right.

[0007] As a preferred technical solution of this application, the annular lamp holder is provided with a plurality of fitting slots arranged in a circular array, and the supplementary light is fitted inside the fitting slots.

[0008] As a preferred technical solution of this application, the connector includes a U-shaped seat that is slidably sleeved on the top plate, a telescopic rod that is rotatably disposed at the bottom of the U-shaped seat, and a connecting rod disposed at the bottom of the telescopic rod for connecting the top ring light strip.

[0009] As a preferred technical solution of this application, the U-shaped seat is fixed to the top plate by locking bolts, a water pipe connector is provided on the top of the U-shaped seat, a through hole is provided on the top plate, the telescopic rod is a hollow structure, and the water supply pipe is connected to the spray head through the water pipe connector.

[0010] As a preferred technical solution of this application, a reflector with a total reflection mirror is installed between adjacent top annular light strips.

[0011] The present invention also discloses a method for bidirectional light supply to the leaves of a plant factory, based on the light supply device, comprising: each top ring light strip has the same rotation direction, each bottom ring light strip has the same rotation direction, but the top ring light strip and the bottom ring light strip have opposite rotation directions. The rotational relationship between the top and bottom ring light strips is as follows: The line segment connecting the centers of the top and bottom ring light strips is defined as the baseline. The midpoint of the illuminated supplementary light is taken as the reference point. The angle between the reference point of the top ring light strip and its center along the rotation direction to the baseline is the top rotation angle. The angle between the reference point of the bottom ring light strip and its center along the rotation direction to the baseline is the bottom rotation angle. Therefore, during rotation, the top rotation angle of the top ring light strip is equal to the bottom rotation angle of the four adjacent bottom ring light strips.

[0012] Preferably, the top rotation angles of each top ring light strip are equal.

[0013] Preferably, the ring-shaped light strip rotates in the opposite direction every 360 degrees.

[0014] Compared with the prior art, the present invention provides a bidirectional light supply device and method for plant factory leaves, which has the following beneficial effects: A bottom ring light strip is installed along the cultivation holes at the top of the cultivation board, and a top ring light strip is installed on the top plate through connectors. This can provide light to the top and bottom leaves of the plant at the same time, effectively solving the problem of insufficient light for the middle and lower leaves and bottom leaves of the plant caused by the existing single top light source. This promotes the overall photosynthesis of the plant, improves the light energy utilization rate and the uniformity of plant growth. The layout employs a top ring light strip with four bottom ring light strips. By utilizing the light supply method, it achieves time-segmented light coverage in four directions of the plant, enabling simultaneous light supply from above and below and simulating changes in natural light. At the same time, it achieves light strip sharing, eliminating light waste.

[0015] 3. Both the bottom and top ring light strips can rotate along their central axis and can rotate independently at different cycles. This allows the lighting area to be dynamically changed when the lamp is installed on a certain arc segment, avoiding the burning phenomenon caused by a fixed light source shining directly on the same part of the leaf for a long time. At the same time, there is no need to frequently switch the light source to simulate changes in light, which significantly reduces the switching loss of the lamp and extends the service life of the light source. 4. Sprinkler heads are installed at the bottom of the top ring light strip, and the telescopic rod is designed as a hollow structure, which is connected to the external water supply pipeline through the water pipe connector, realizing the integrated layout of lighting and irrigation functions; 5. The height and horizontal position of the top ring light strip can be adjusted by the design of the U-shaped seat, telescopic rod and connecting rod in the connector; the U-shaped seat is fixed to the top plate by locking bolts, which is convenient for disassembly and assembly; the bottom ring light strip can be flexibly arranged into multiple ring arrays according to the position of the cultivation holes, which has strong adjustability and expandability, and can adapt to plant varieties with different heights and light requirements as well as plant factory layouts of different sizes. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is the front view of the present invention; Figure 3 This is a structural diagram of the cultivation board and the bottom annular light strip of the present invention; Figure 4 This is a structural diagram of the top plate, connector, and top annular light strip of the present invention; Figure 5 This is a specific embodiment of the positional relationship between the ring-shaped light strip, the supplementary light, and the baseline in this invention.

[0017] In the picture: 100. Cultivation board; 101. Top plate; 102. Cultivation hole; 103. Reflector; 200. Bottom ring light strip; 201. Ring light holder; 202. Supplemental light; 300. Connector; 301. U-shaped seat; 302. Telescopic rod; 303. Connecting rod; 304. Locking bolt; 305. Water pipe connector; 400. Top ring light strip; 500. Sprinkler head; 600. Drive motor; 601. Drive gear; 602. Driven gear. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Example

[0019] Reference Figure 1-4 A plant factory leaf bidirectional light supply device includes a cultivation board 100, a top plate 101 disposed above the cultivation board, and cultivation holes 102 disposed on the top of the cultivation board 100. Nutrient solution pipes are provided at the bottom of the cultivation holes 102 for adding nutrient solution. Multiple sets of bottom annular light strips 200 for providing light to the bottom of the plants are arranged in a ring array along the cultivation holes 102 on the top of the cultivation board 100. A top annular light strip 400 for providing light to the top of the plants is disposed on the outer wall of the top plate 101 through a connector 300. Both the bottom annular light strip 200 and the top annular light strip 400 are rotated along their central axis by a drive mechanism. A spray head 500 is also provided at the bottom of the top annular light strip 400. Specifically, by installing a top ring light strip 400 above the cultivation plate 100 and a bottom ring light strip 200 around the cultivation holes 102, bidirectional synchronous lighting of the top and bottom leaves of the plant is achieved, effectively solving the problem of insufficient light for the middle and lower leaves and bottom leaves caused by traditional single top light sources. At the same time, the bottom and top light strips can rotate independently, dynamically adjusting the lighting area and avoiding scorching caused by prolonged direct exposure of the same leaf surface by a fixed light source, reducing switching losses and extending the lifespan of the light source. The sprinkler head 500 integrates lighting and irrigation functions, improving system integration.

[0020] Both the bottom ring light strip 200 and the top ring light strip 400 include a ring light frame 201 and a supplementary light 202 embedded inside the ring light frame 201. By embedding the supplementary light 202 inside the ring light frame 201, a ring light strip with a compact structure and uniform light distribution is formed, which facilitates ring-shaped supplementary lighting for the plant canopy and bottom leaves, improves the uniformity and efficiency of light, and facilitates modular installation and maintenance.

[0021] The ring-shaped lamp holder 201 has multiple fitting slots arranged in a ring array, and the supplementary light lamps 202 are fitted inside the fitting slots. The ring array layout of the fitting slots allows the supplementary light lamps 202 to be evenly distributed on the ring-shaped lamp holder 201 as needed, further optimizing the angle and density of light, avoiding blind spots or excessively strong light spots in some areas, and improving the light energy utilization rate and the uniformity of plant growth.

[0022] The connector 300 includes a U-shaped seat 301 slidably fitted on the top plate 101, a telescopic rod 302 rotatably set at the bottom of the U-shaped seat 301, and a connecting rod 303 set at the bottom of the telescopic rod 302 for connecting the top ring light strip 400. The connector 300 structure enables flexible adjustment of the top ring light strip 400 in both height and horizontal direction, which can adapt to the light requirements of plants of different heights, facilitate the adjustment of the distance and angle between the light strip and the top of the plant, and enhance the applicability and operability of the device, especially suitable for plant factory cultivation scenarios with multiple varieties and multiple growth stages.

[0023] The U-shaped base 301 is fixed to the top plate 101 by locking bolts 304. A water pipe connector 305 is located on the top of the U-shaped base 301. A through hole is provided on the top plate 101. The telescopic rod 302 has a hollow structure. The water supply pipe is connected to Q via the water pipe connector 305 and is connected to the sprinkler head 500. The hollow telescopic rod 302 serves both as structural support and as a water channel, reducing the entanglement and interference of external pipes. The U-shaped base 301 is detachable and easy to maintain and expand. Overall, this improves the system's integration, reliability, and space utilization.

[0024] Furthermore, a first drive motor 600 is connected to the side wall of the U-shaped base 301 via a mounting plate. The output end of the drive motor 600 is connected to a drive gear 601, which meshes with a driven gear 602. The driven gear 602 is fixedly connected to the outer wall of the telescopic rod 302. Through the drive motor 600, drive gear 601, and driven gear 602, the top ring light can be rotated. During the rotation, the light direction can be changed evenly, so that the light emitted by the supplementary light lamp 202 always sweeps across the top leaf surface of the plant at different angles. This avoids the light suppression or scorching caused by a fixed light source shining directly on the same part for a long time. At the same time, it simulates the changes in the light angle in nature, which is beneficial to the establishment of plant morphology.

[0025] The bottom ring light strip 200 is connected to a drive motor via a connecting shaft. Driven by the drive motor, the bottom ring light strip 200 rotates, providing better illumination to the bottom of the plant leaves.

[0026] It should be noted that only a portion of the arc of the ring light stand 201 is equipped with supplementary lights 202, for example, only the arc with a 90-degree central angle is equipped with lights. Furthermore, the top ring light strip 400 can be set to rotate once every 24 hours and the bottom ring light strip 200 can be controlled to rotate once every 96 hours through the control system. This operation can be adjusted according to the specific growth of the plant. The control system can use a conventional PLC control system, which is a mature technology, so it will not be elaborated further in this application.

[0027] Specifically, when using this plant factory leaf surface bidirectional light supply device: depending on the plant variety, plant height, and cultivation density, first adjust the height and horizontal position of the top ring light strip 400 through the connector 300. Specifically: slide the U-shaped seat 301 along the top plate 101 to the appropriate position, and then fix it with the locking bolt 304; then adjust the extension length of the telescopic rod 302 so that the top ring light strip 400 below the connecting rod 303 is at a suitable distance above the plant canopy. At the same time, the bottom ring light strip 200 is pre-installed around each cultivation hole 102 of the cultivation plate 100.

[0028] Electrical wires, control lines, water pipes, etc. can be arranged inside the hollow top plate 101. Conduit interfaces are provided at certain intervals below the top plate 101. After the U-shaped base 301 is fixed, the conduit interfaces on the top plate 101 are connected to the lamps and nozzles through external conduits.

[0029] like Figure 2 As shown, a reflector 103 with a total reflection mirror can be installed between adjacent top ring light strips to prevent the light from the top ring light strips from shining on the plants near the cultivation holes and to improve the light utilization rate for the plants below. The reflector 103 can also better reflect the light from the top ring light strips to the lower part of the plants.

[0030] The supplemental lights 202 in the top ring light strip 400 and the bottom ring light strip 200 are powered on and lit at the same time. The top ring light strip 400 emits light from above the plant and illuminates the top leaves of the plant. The bottom ring light strip 200 is distributed in a ring array along the cultivation hole 102. The light emitted by it illuminates the middle and lower parts of the plant and the bottom leaves from below or the side of the plant, which makes up for the problem of insufficient light in the lower part caused by a single top light source and realizes bidirectional light supply to the leaves. To avoid scorching of the same leaf surface due to prolonged direct exposure to a fixed light source, and to simulate changes in the angle of natural light, the top annular light strip 400 and the bottom annular light strip 200 rotate independently along their central axes via their respective drive mechanisms. The drive motor 600 is fixed to the mounting plate on the side wall of the U-shaped base 301, and its output drives the drive gear 601 to rotate. The drive gear 601 meshes with the driven gear 602 coaxially fixed to the outer wall of the telescopic rod 302, thereby causing the telescopic rod 302 and the connecting rod 303 to rotate around their own axes. Because the top annular light strip... The top ring light strip 400 is fixed to the bottom of the connecting rod 303, so the top ring light strip 400 also rotates along its central axis. By controlling the speed, direction and start / stop cycle of the drive motor 600, the top ring light strip 400 can dynamically change the illumination area according to the set mode. Similarly, the bottom ring light strip 200 is also equipped with an independent drive mechanism, which allows it to rotate independently around the central axis of the cultivation hole 102. The rotation cycle, direction and speed of the top and bottom light strips can be set separately according to the plant species, growth stage and light requirements, without interfering with each other. The water supply pipeline connects to the water pipe connector 305 at the top of the U-shaped base 301 via an external water source. The water flows through the through hole on the top plate 101, enters the internal channel of the hollow telescopic rod 302, and finally reaches the sprinkler head 500 from the bottom or side of the connecting rod 303 and sprays out. The sprinkler head 500 is located at the bottom of the top ring light strip 400. It rotates synchronously with the top light strip, so that water or nutrient solution is evenly sprayed on the plant canopy and leaf surface. The nutrient solution delivery pipeline can also be connected below the plant cultivation hole to realize the integrated operation of light supply and irrigation.

[0031] In one specific embodiment, supplementary lights 202 are installed on only a quarter-circumference segment of each annular light fixture 201. In the vertical projection direction, four bottom annular light strips 200 are distributed vertically and horizontally around each top annular light strip 400, such as... Figure 5 As shown, based on such a light supply device, in order to coordinate the rotation angles of each ring lamp holder so that the bottom and top receive the same amount of light, the present invention employs a light supply method, specifically including: The rotation directions of each top ring light strip 400 are the same, and the rotation directions of each bottom ring light strip 200 are the same, but the rotation directions of the top ring light strip and the bottom ring light strip are opposite. For example, the top ring light strip rotates entirely clockwise, while the bottom ring light strip rotates entirely counterclockwise.

[0032] The rotational relationship between the top and bottom ring light strips is as follows: the line segment connecting the centers of the top and bottom ring light strips is defined as the baseline, and the midpoint of the illuminated supplementary light 202 is defined as the reference point. The angle between the reference point of the top ring light strip and the center of the top ring light strip along the rotation direction of the top light strip to the baseline is the top rotation angle, and the angle between the reference point of the bottom ring light strip and the center of the bottom ring light strip along the rotation direction of the bottom light strip to the baseline is the bottom rotation angle. Therefore, during rotation, the top rotation angle of the top ring light strip is equal to the bottom rotation angle of the four adjacent bottom ring light strips.

[0033] like Figure 5 As shown, the center of the top ring light strip 400 is C1, the center point of the supplementary light 202 is D1, the centers of the bottom ring light strip 200 to the left and below the top ring light strip are C2 and C3 respectively, and the centers of the supplementary lights are D2 and D3 respectively. Then, the line C1C2 connecting C1 and C2 is the baseline for the bottom ring light strip to the left, and the line C2C3 connecting C1 and C3 is the baseline for the bottom ring light strip to the lower.

[0034] When the baseline is C1C2, the angle J1 between the baseline point D1 of the top ring light strip and the center C1 of the top ring light strip, along the rotation direction of the top light strip to the baseline C1C2, is the top rotation angle. Figure 5 As shown, when J1=15 degrees, the bottom rotation angle of the left bottom ring light strip is J2, so J1=J2=15 degrees.

[0035] When the baseline is C1C3, the angle J3 formed by the line C1D1 connecting the baseline point D1 of the bottom ring light strip and the center C1 of the top ring light strip along the rotation direction of the top light strip to the baseline C1C3 is the top rotation angle. Figure 5 As shown, when J3 = 285 degrees, the bottom rotation angle of the lower circular light strip is J4, therefore J3 = J4 = 285 degrees. Note that... Figure 5 In the equation, J3 represents the angle at which C1D1 rotates clockwise to C1C3, and J4 represents the angle at which C3D3 rotates counterclockwise to C1C3.

[0036] Combination Figure 5 Analysis shows that when the top rotation angle and the bottom rotation angle are the same, and the bottom and top rotation directions are opposite, the area of ​​the plant illuminated by the supplemental lights at the bottom and top can be the same at all times. The bottom and top of the plant may be illuminated or not illuminated at the same time, which is consistent with the lighting conditions in nature.

[0037] Similar conclusions can be drawn from the analysis of the bottom ring light strips on the lower and right sides.

[0038] At the same time, when Figure 5 As shown, when using a shared bottom ring light strip, the bottom ring light strip is set at the midpoint of the line connecting the two top ring light strips TOP1 and TOP2 corresponding to adjacent plant cultivation holes D. If the rotation angle of all top ring light strips is set to be equal, then each bottom ring light strip can simultaneously illuminate the plants from above, below, left, and right. This allows each bottom ring light strip to be used simultaneously to illuminate the plants corresponding to the four top ring light strips. Figure 5 As shown, the bottom ring light strips in the center of TOP1 and TOP2 illuminate TOP2 when the supplemental light is not aligned with TOP1. This demonstrates that by using each top ring light strip to correspond to four bottom ring light strips, the plant is provided with light coverage in four directions at different times, simulating the changes in natural light. It also allows for the sharing of light strips, eliminating any waste of light.

[0039] To avoid cable tangling and shorten cable usage during rotation, each top ring light strip can be limited to rotating 360 degrees before rotating in the opposite direction, with the bottom ring light strip adjusting its direction accordingly. For example, it can rotate clockwise once, then counterclockwise once, and repeat this cycle.

[0040] Compared to existing technologies, the light supply device of this invention features a bottom ring-shaped light strip along the cultivation holes at the top of the cultivation board, and a top ring-shaped light strip connected to the top plate via connectors. This allows for simultaneous illumination of the top and bottom leaves of the plant, effectively solving the problem of insufficient light for the middle and lower leaves caused by a single top light source. This promotes overall photosynthesis, improves light energy utilization, and enhances the uniformity of plant growth. The light supply method of this invention employs a layout where each top ring-shaped light strip corresponds to four bottom ring-shaped light strips. This method achieves time-segmented light coverage in four directions, providing simultaneous light from above and below, and simulating changes in natural light. Furthermore, it enables light strip sharing, eliminating light waste.

[0041] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A bidirectional light supply device for the leaves of a plant factory, comprising a cultivation board (100), a top plate (101) disposed above the cultivation board, and cultivation holes (102) disposed on the top of the cultivation board (100), characterized in that, The top of the cultivation board (100) is arranged in a ring array along the cultivation holes (102) with multiple sets of bottom ring light strips (200) for providing light to the bottom of the plants. The outer wall of the top plate (101) is provided with a top ring light strip (400) for providing light to the top of the plants via a connector (300). Both the bottom ring light strip (200) and the top ring light strip (400) are rotated along their central axis by a drive mechanism. The bottom of the top ring light strip (400) is also provided with a spray head (500).

2. The plant factory leaf surface bidirectional light supply device according to claim 1, characterized in that, The bottom annular light strip (200) and the top annular light strip (400) both include an annular light frame (201) and a supplementary light (202) embedded inside the annular light frame (201).

3. A bidirectional light supply device for plant factory leaves according to claim 2, characterized in that, The arc length of the supplementary light distributed on the ring light strip corresponds to a central angle of 90 degrees; in the vertical projection direction, each top ring light strip (400) has four bottom ring light strips (200) distributed up, down, left, and right.

4. A bidirectional light supply device for plant factory leaves according to claim 2, characterized in that, The ring lamp holder (201) has multiple fitting slots arranged in a ring array, and the supplementary light (202) is fitted inside the fitting slots.

5. A bidirectional light supply device for plant factory leaves according to claim 4, characterized in that, The connector (300) includes a U-shaped seat (301) slidably sleeved on the top plate (101), a telescopic rod (302) rotatably disposed at the bottom of the U-shaped seat (301), and a connecting rod (303) disposed at the bottom of the telescopic rod (302) for connecting the top ring light strip (400).

6. A bidirectional light supply device for plant factory leaves according to claim 5, characterized in that, The U-shaped seat (301) is fixed to the top plate (101) by locking bolts (304). A water pipe connector (305) is provided on the top of the U-shaped seat (301). A through hole that matches the water pipe connector is provided on the top plate (101). The telescopic rod (302) is a hollow structure. The water supply pipe is connected through the water pipe connector (305) and communicates with the spray head (500).

7. A plant factory leaf surface bidirectional light supply device according to claim 1, characterized in that, A reflector (103) with a total reflection mirror is installed between adjacent top ring light strips.

8. A method for bidirectional light supply to the leaves of a plant factory, characterized in that, The light supply device as described in claim 3 includes: each top annular light strip has the same rotation direction, each bottom annular light strip has the same rotation direction, but the top annular light strip and the bottom annular light strip have opposite rotation directions. The rotational relationship between the top and bottom ring light strips is as follows: The line segment connecting the centers of the top and bottom ring light strips is defined as the baseline. The midpoint of the illuminated supplementary light is taken as the reference point. The angle between the reference point of the top ring light strip and its center along the rotation direction to the baseline is the top rotation angle. The angle between the reference point of the bottom ring light strip and its center along the rotation direction to the baseline is the bottom rotation angle. Therefore, during rotation, the top rotation angle of the top ring light strip is equal to the bottom rotation angle of the four adjacent bottom ring light strips.

9. A method for bidirectional light supply to the leaves of a plant factory according to claim 1, characterized in that, The top rotation angles of each of the top ring light strips are equal.

10. A method for bidirectional light supply to the leaves of a plant factory according to claim 1, characterized in that, The ring-shaped light strip rotates in the opposite direction every 360 degrees.

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