EP3341762A1 - Distributed seismic source array for use in marine environments - Google Patents
Distributed seismic source array for use in marine environmentsInfo
- Publication number
- EP3341762A1 EP3341762A1 EP16839990.5A EP16839990A EP3341762A1 EP 3341762 A1 EP3341762 A1 EP 3341762A1 EP 16839990 A EP16839990 A EP 16839990A EP 3341762 A1 EP3341762 A1 EP 3341762A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- face plates
- marine
- sound source
- pressure
- original
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/38—Seismology; Seismic or acoustic prospecting or detecting specially adapted for water-covered areas
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/02—Generating seismic energy
- G01V1/143—Generating seismic energy using mechanical driving means, e.g. motor driven shaft
- G01V1/145—Generating seismic energy using mechanical driving means, e.g. motor driven shaft by deforming or displacing surfaces, e.g. by mechanically driven vibroseis™
Definitions
- the present invention relates to an improved means of imparting low frequency vibrations in the earth for seismic exploration and monitoring, sonar applications, or any other application that would benefit from having a precisely controlled, small, powerful, highly efficient, reliable, and repeatable low frequency acoustic source.
- I mpulsive sound sources used for seismic exploration and monitoring such as dynamite or air guns have been blamed for harming the environment, marine mammals, and other sea life.
- a vibratory source such as a marine vibrator that can impart controlled vibrations over a period of many seconds as compared to milliseconds of an impulsive source has many advantages.
- I mpulsive sound sources create significant broad band noise (up to 1 kHz) with much of it outside the useable seismic frequency band. Although frequencies above about 100 Hz are typically not seismically useful, they are blamed for the preponderance of the harm to marine life.
- a controlled vibratory source that can be limited to approximately 100 Hz would eliminate this concern.
- a precisely controlled vibratory source that is highly repeatable can improve imaging results as compared to impulsive sources which are less repeatable.
- a marine vibrator must have dimensions much smaller than the wavelength of the sound that it produces. I n water for example, at 100 Hz the acoustic wavelength is about 50 feet, but an acceptable size for a marine vibrator is probably three feet or less. Achieving high power at low frequencies from a small transducer requires very large volume displacements, up to hundreds of liters of water, which is at the very limits or possibly even beyond the limits of traditional technologies. For example, one current solution uses a magnetostrictive material (Terfenol-D) with a very high displacement.
- Terfenol-D magnetostrictive material
- Terfenol-D which has the highest magnetostriction of any known alloy provides only about 1/16 inch of displacement from a 3- foot stack.
- innovative flextensional transducers designed to leverage these small displacements into larger displacements, but flextensional transducers are heavy, expensive, and highly resonant.
- voice coil actuators as drivers have also been developed for the marine vibrator application, but they have limited output and also have problems with resonant peaks.
- a Gas-Filled Bubble Seismo-Acoustic device was also developed for this application but it too cannot generate the signals anywhere near the bandwidth and power needed.
- the present invention is generally directed to a marine sound source configured for use in a marine environment having one or more moveable plates (which can be flexible
- a rotary motor and a connection means (either a crank shaft coupled with at least one connecting rod or a camshaft) between the rotary motor and the one or more moveable plates configured to translate rotary motion of the motor into linear motion of the one or more moveable plates.
- the movable plates can be connected to an external housing via a flexible, watertight seal to form a pressure boundary between an internal portion of the housing and an external portion of the housing and the internal portion can be internally pressurized to coincide with fluid pressure external to the housing.
- One way of pressurizing the internal portion is to fill it with an internal fluid which equalizes with external fluid pressure via a plurality of ports in a periphery of the housing located orthogonal to a linear motion of the one or more movable plates.
- the internal fluid can have a higher cavitation threshold than water and be isolated from the external fluid via a bladder.
- the amount of linear displacement of the one or more movable plates can be varied by passive means based upon the speed of rotation of the rotary motor. For example, changes in linear displacement can be accomplished via a spring loaded rod which decreases in length with applied load as the rotary motor increases in speed and the spring is compressed or by a mechanical linkage and movement of at least one weight due to changes in centrifugal force as the speed of the rotary motor changes.
- the amount of linear displacement of the one or more movable plates can also be varied by active means independently of the speed of rotation of the rotary motor.
- Two opposed transducer face plates can be joined together by at least one mechanical connection to cause the two opposed transducer face plates to move in unison such that a front plate radiates pressure waves outwardly from its face in a primary sound pressure radiation direction while the second transducer face plate is a back plate.
- a pressure deflecting plate (which may be coupled to a weight to form a deflecting plate structure with more mass), which is preferably configured so that it has a mass many times the mass of water displaced by the front plate, can be configured so water volume displaced from the back plate is redirected orthogonal to movement of the back plate or redirected in a direction to cancel out the force from the front plate.
- two transducers can be configured in a back to back configuration in which the primary sound pressure radiation direction from one transducer and the second primary sound pressure radiation direction from the other transducer are opposite each other and water displaced between the first transducer and the second transducer will be directed orthogonal to the movement of the first and second set of two opposed transducer face plates.
- Fig. 1 shows top and cross sectional views of a marine vibrator in accordance with the present invention using an eccentric crankshaft.
- Fig. 2 illustrates an alternative embodiment of a marine vibrator camshaft cross section.
- Fig. 3 illustrates a flextensional transducer used for imparting low frequency sound waves into water while Fig. 4 illustrates how it can be replaced by a rotating camshaft in accordance with the present invention.
- Fig. 5 illustrates an additional pressure compensation method in accordance with the present invention used in a marine environment while Fig. 6 illustrates use of an isolating bladder in the embodiment of Fig. 5.
- Fig. 7 illustrates an alternative embodiment of a marine vibrator in accordance with the present invention that uses a dual shaft.
- Fig. 8 illustrates how the speed of a motor changes a marine vibrator's Sound Pressure Level for a fixed displacement
- Fig. 9 illustrates how changing the displaced volume as the frequency is increased allows the Sound Pressure Level to remain relatively constant.
- Figs. 10 and 11 illustrate potential embodiments for changing the displacement of a marine vibrator.
- Fig. 12 illustrates an embodiment of the present invention in which a rotary motor turns a crankshaft that is connected to one of two opposed moveable transducer face plates via a connecting rod.
- Fig. 13 illustrates the embodiment of Fig. 12 in which a pressure deflecting plate is located on the side opposite the primary sound pressure radiation direction and the back plate's displaced water volume is redirected orthogonal to its movement.
- Fig. 14 illustrates a pressure deflecting plate similar to that of Fig. 13 except that the pressure deflecting plate directs the displaced water volume from the back plate in a direction to cancel out the force from the front plate.
- Fig. 15 illustrates an array of marine vibrators deployed attached to a ship and Fig. 16 illustrates it deployed attached to an offshore oil platform.
- the present invention relies upon a marine vibrator, or a series of marine vibrators aligned in an array, to radiate acoustic energy into a marine environment (i.e., a body of water, such as a lake, sea or ocean) that penetrates a solid bottom of the marine environment (e.g., lakebed, seabed or an ocean bed) which is then reflected back to receivers located either on the solid bottom or in the water of the marine environment itself. These reflections are used to generate images of the subsea surface.
- a marine environment i.e., a body of water, such as a lake, sea or ocean
- a solid bottom of the marine environment e.g., lakebed, seabed or an ocean bed
- An array of marine vibrators in accordance with the present invention can be towed behind a ship (see Fig. 15), tethered from an offshore oil platform at a depth anywhere from just below the surface to the sea bottom (see Fig. 16), or it can be trenched (buried) beneath the sea floor. If placed on the sea floor bottom a cover may be placed over the marine vibrators to direct the acoustic energy into the sea bottom and limit acoustic energy from entering the seawater above (minimizing harm to sea creatures).
- an array of marine vibrators is tethered to an offshore oil platform
- the other end can be attached to a small craft such that it can be easily repositioned (rotated) during a seismic survey. It can also be positioned (tethered) between two boats.
- tow depth can be maintained by flotation devices, depth control buoys, or similar means.
- a marine vibrator may also be mounted to the underside of a boat with the source projecting energy downward.
- a marine vibrator must cyclically displace large volumes of water over the seismic band of interest, which for purposes of the present invention is approximately 1 - 100 Hz.
- the current invention does this by moving a large, relatively stiff plate or plates (transducer face plates).
- the preferred embodiment of the current invention is to use an electric motor (preferably an AC servo motor) to drive the displacement of the transducer face plate via a crankshaft and connecting rod(s). Since AC servo motors have a high and relatively constant torque from startup (0 rpm) up to their rated speed, this eliminates the "peakiness" inherent in traditional transducer designs. In addition, the servo motor is highly efficient over its entire operating speed range (transducer frequency band) unlike magnetostrictive or voice coil powered transducers. Speed control is simple and precise as the traditional servo drives incorporate positional feedback control via encoders or resolvers installed within the servo motor. Constant speed, linear ramps, non-linear ramps, and stepped ramp frequency sweeps either manual or programmed are all possible with today's servo drive controllers.
- an electric motor preferably an AC servo motor
- RMS Root Mean Square
- SPL Sound Pressure Level
- An especially preferred embodiment of the current invention uses state-of-the-art factory automation and programmable logic technology to precisely control small powerful rotary motors that are connected via crankshaft or camshaft to drive transducer face plates at the exact displacement and force needed for the marine vibrator application.
- This technology is capable of producing vibrations and sound far beyond the capabilities of traditional acoustic devices, while minimizing the unnecessary out-of-band signals that can potentially harm marine life.
- the external transducer radiating surfaces (such as transducer face plates) must displace 10-100 liters of water many times per second.
- published industry requirements require operation from 5 Hz to 100 Hz.
- the ratio of internal volume to swept volume of the radiating surfaces must be about 10:1 or less. So, if the displaced volume is 100 liters, the internal volume should be 1000 liters or less. At atmospheric pressure the internal volume will be at 14.7 psia. For this example, moving the face plates to displace 100 liters will cause the internal pressure to change by approximately 10 % or 1.5 psi assuming ideal gas laws.
- the transducer drive mechanism must overcome as a minimum 1.5 psi times the transducer surface area (i.e., 1400 square inches) which equates to 2100 pounds of force.
- the present invention also incorporates features to eliminate the internal pressure changes brought on by movement of the transducer radiating surfaces which in our case are the transducer face plates.
- the internal transducer volume is kept relatively constant as the transducer face plates(s) move to displace the desired external water volume. Because there is no change in internal volume as the transducer face plates move to displace the desired volume of water, there is no cyclic change in internal pressure that has to be overcome by the transducer's drive mechanism.
- Fig. 1 illustrates an embodiment of the present invention in which a motor with an eccentric crankshaft can be used to moving flexing plate(s).
- the eccentric crankshaft is connected to the flexural disk plates at their approximate center point via connecting rods.
- At least one stiff support member rigidly attached to cylindrical housing provides the means for supporting the drive motor and the crankshaft.
- the inside of the cylinder is air-filled and when the vibrator is placed in the water it will be entirely surrounded by water.
- the speed of the motor controls the frequency of the vibrations and it can be swept to give the desired output signal.
- a monitoring accelerometer can be placed on either or both of the flexural disks (on the air side) to record actual vibrator performance.
- the configuration described above can be modified to use just a single connecting rod to vibrate just one flexural disk so that the acoustic wave is directed to one side only.
- appropriate means to support and balance the marine vibrator i.e., provide a reaction force, etc.
- the flexural disks are designed to temporarily deform (i.e., flex) with the up and down motion of the connecting rods.
- the discs can be more rigid with a piston seal or other edge type seal (designed for dynamic sealing) around their outer edge such that the whole disk moves up and down with the piston seal preventing leakage.
- the piston can be attached to the underside of a thin flexible sheet such as rubber (or reinforced rubber) with the rubber sheet attached to the outer housing forming the watertight seal. The rubber will allow up and down motion of the piston while maintaining a watertight seal.
- the system can pressure compensated if needed by pressurizing the internal air filled section manually or automatically to balance the force across the piston/disk to minimize the differential pressure across the disks for operation at increased water depths.
- the eccentric crankshaft can be replaced by a camshaft (acting directly or via pushrods) operating against spring pressure that operates to pull the opposing disks together.
- the camshaft high lobes and low lobes are opposed (see Fig. 2) such that the opposing disks are pushed outward against spring pressure and pulled inward (with spring pressure) in unison.
- cam followers can be used.
- the most widely-used method of imparting controlled low frequency sound waves into water is the flextensional transducer (a cross section is shown in Fig. 3). Because piezo ceramic materials generate high forces but small displacements, the flextensional transducer was designed to translate small motion of the ceramic stack into large motion of the outer shell. If desired, the motor, eccentric crankshaft, and connecting rods described above can be used to replace ceramic stack in the flextensional transducer preferably acting to flex the walls of the outer elastic shell along the minor axis, however, it will work in either axis.
- the piezoceramic stack can also be replaced with a rigid frame and a rotating camshaft (see Fig. 4). In this case, the elastic outer shell is prestressed to always maintain a compressive force on the camshaft. As the camshaft rotates, the linear motion of the rigid frame causes the minor axis of the outer shell to flex imparting vibration into the water.
- the internal portion of the marine vibrator source be filled with a gas (typically air), and that the pressure of the gas can be adjusted to compensate for increasing water depth.
- a gas typically air
- An alternate means is to have liquid on both sides of the moving transducer plates/pistons (see Fig. 5) such that the pressure across the plates remains equalized with depth.
- the pressure release ports ensure equal pressure and allow a pressure release which is necessary for proper operation upon movement of the plates/pistons. While Fig. 5 shows the new pressure compensation approach using the eccentric crankshaft design, the new pressure compensation approach can be used across all of the marine vibrator designs described in this application including the flextensional transducer design.
- the simplest way to obtain pressure equalization is to allow the liquid that the transducer is immersed in (such as seawater) to freely flow inside and outside the transducer through the pressure release ports. This is not always ideal as in the case of seawater, it tends to be corrosive, dirty, etc. To get around this, the inside liquid and the outside liquid can be separated by a flexible bladder type device (see Fig. 6) that allows the pressure to be equalized with intermixing of the fluids.
- FIG. 7 An alternate configuration of the marine vibrator is shown in Fig. 7.
- a motor with a dual shaft continuously shaft protruding from opposite ends of the motor. This allows the motor to be positioned near the centered of the transducer. Again, where the picture depicts operation via eccentric crankshafts, operation via camshaft is also possible.
- the marine vibrator's output level (typically referred to as Sound Pressure Level or SPL) be relatively constant over its frequency range (frequency is controlled by the speed of rotation of the motor).
- SPL Sound Pressure Level
- the previously discussed marine vibrator embodiments had a fixed displacement (area swept by the moveable pistons).
- the SPL changes accordingly (see Fig. 8).
- the SPL increases from about 170 dB to 210 dB when going from 10 Hz to 100 Hz.
- the SPL can be kept relatively constant over the marine vibrator's frequency range if the displacement of the pistons is not fixed but rather can be changed with frequency.
- Fig. 9 depicts how by changing the displaced volume as the frequency is increased from 10 Hz to 100 Hz, the SPL stays relatively constant. (In actuality by changing the displacement appropriately with frequency the SPL can be lower, the same, or higher as the frequency of the marine vibrator is changed from 10 Hz to 100 Hz.)
- the mechanism moving the piston(s) In order to change the displacement (piston swept volume) with frequency, the mechanism moving the piston(s) must change its stroke length as the frequency is changed. In other words as the frequency (or rotation speed of the motor) is increased, the stroke must decrease.
- the camshaft approach this can be accomplished by changing the length or stroke of the pushrod between the rotating camshaft and the moveable piston(s).
- the crankshaft approach this can be accomplished by changing the length or stroke of the connecting rod between the crankshaft and the piston(s) as the speed of rotation changes.
- Fig. 10 shows one possible embodiment.
- FIG. 11 depicts an example of where centrifugal force is used to change the position of a pushrod.
- a simple adaptation of this concept is envisioned as one means of implementing this approach.
- active means may also be used.
- active means include electrically driven actuators/positioning systems, pneumatic/hydraulic driven actuators/positioning systems, controllable variable viscosity fluids, to name just a few.
- Fig. 12 One preferred embodiment of the present invention is illustrated in Fig. 12.
- a rotary motor turns a crankshaft that is connected to one of the face plates via a connecting rod.
- the stroke of the connecting rod is varied by any of the means described in this invention by changing the distance designated by the red double-headed arrow.
- Flexible waterproof seals between the transducer housing and face plates allow easy movement of the face plates while maintaining a leak proof seal.
- the face plates are connected internally via multiple rigid connecting posts. These connecting posts cause both face plates to always move in the same direction and by the same amount as the crank shaft is rotated.
- the internal volume is kept relatively constant and accordingly the internal pressure remains essentially constant.
- the internal pressure can and should still be equalized with external pressure (depth) as needed to prevent collapsing of the housing and to reduce stress on any load bearing internal components.
- massive can be defined as having a mass that is many times the mass of the water volume displaced by the primary face (a ratio of 10:1 or greater is preferred).
- FIG. 14 Another method to balance the resultant forces is shown in Fig. 14.
- the pressure deflecting plate directs the displaced water volume from the "back” plate in a direction to cancel out the force from the "front” plate.
- the "front” plate pushes outward it will tend to force the entire transducer in the opposite direction.
- the "back” plate moves inward and the displaced water creates an equal and opposite suction force which acts as a restoring force preventing the entire transducer from moving.
- Figs. 11-14 show connecting posts between opposing transducer face plates in all of the diagrams. Among other things, these connecting posts ensure equal movement of both face plates. Even without the connecting posts the opposing face plates will automatically move in conjunction with each other in order to maintain internal pressure essentially constant.
- Figs. 11-14 also show in all diagrams a single connecting rod from the rotating crank shaft to one of the transducer face plates. It is also possible to link the motion of the opposing face plates together by having a connecting rod from each face plate connected to the rotating crank shaft.
- Figs. 11-14 all have a red double-headed arrow to indicate that stroke length can be varied.
- Some of the means of varying the stroke length include changing passively with centrifugal force or actively via a motor operated lead screw.
- the present invention includes at least the following embodiments and variations in such embodiments.
- a marine sound source having one or more moveable plates, at least one rotary motor and a connection means between the rotary motor and the moveable plate(s) capable of translating the rotary motion of the motor into linear motion of the moveable plate(s).
- connection means is a crank shaft and connecting rod(s).
- connection means is via camshaft.
- rotary motor is an electric motor.
- connection means includes a method of varying the amount of linear displacement of the moveable plate(s).
- connection means is a crank shaft and connecting rod(s).
- connection means is via camshaft.
- connection means includes a method of varying the amount of linear displacement of the flexing external walls.
- a marine sound source having a rotary motor, a baseplate that imparts vibration onto a surface that it is resting, a moveable mass and a connection means between the moveable mass and the baseplate that translates the rotary motion of the motor into linear motion of the moveable mass such that the cyclical movement of the moveable mass causes vibration of the baseplate.
- connection means is a crank shaft and connecting rod(s).
- connection means is via camshaft.
- a marine sound source having two opposed, moveable transducer face plates attached to an external pressure housing via flexible, watertight seals; at least one rotary motor; a connection means between the rotary motor and at least one of the moveable face plate(s) capable of translating the rotary motion of the motor into linear motion of the moveable plate(s); and a connection means between the two transducer face plates that causes them to move in unison.
- connection means between the two transducer face plates is via a crank shaft and connecting rod(s).
- connection means between the two transducer face plates is via at least one rigid connection post.
- connection means between the rotary motor and at least one of the moveable face plate(s) is via camshaft.
- connection means between the rotary motor and at least one of the moveable face plate(s) is via a crankshaft and connecting rod.
- the marine source of embodiment 32 where the connection means to the rotary motor includes a method of varying the amount of linear displacement of the moveable plate(s).
- massive can be defined as having a mass that is many times the mass of the water volume displaced by the primary face (a ratio of 10:1 or greater is preferred).
- Another method of further mitigating the resultant unbalanced force is a modification of the pressure deflecting plate described in embodiment 48 to direct the displaced water volume from the "back" plate in a direction not orthogonal to the movement of the transducer face plates but rather in a direction to cancel out the force from the "front" plate.
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Remote Sensing (AREA)
- Acoustics & Sound (AREA)
- Environmental & Geological Engineering (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Geophysics (AREA)
- Oceanography (AREA)
- Apparatuses For Generation Of Mechanical Vibrations (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201562209196P | 2015-08-24 | 2015-08-24 | |
PCT/US2016/048201 WO2017035144A1 (en) | 2015-08-24 | 2016-08-23 | Distributed seismic source array for use in marine environments |
Publications (2)
Publication Number | Publication Date |
---|---|
EP3341762A1 true EP3341762A1 (en) | 2018-07-04 |
EP3341762A4 EP3341762A4 (en) | 2019-07-10 |
Family
ID=58100986
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP16839990.5A Withdrawn EP3341762A4 (en) | 2015-08-24 | 2016-08-23 | Distributed seismic source array for use in marine environments |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP3341762A4 (en) |
WO (1) | WO2017035144A1 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10809398B2 (en) | 2017-06-15 | 2020-10-20 | Pgs Geophysical As | Continuous resonance marine vibrator |
CN117492068B (en) * | 2023-12-27 | 2024-04-02 | 吉林大学 | Electrohydraulic ocean controllable seismic source with pressure compensation function |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4332017A (en) * | 1979-08-20 | 1982-05-25 | The Stoneleigh Trust | Mechanoacoustic transducer for use in transmitting high acoustic power densities into geological formations such as oil-saturated sandstone or shale |
US5103130A (en) * | 1988-12-20 | 1992-04-07 | Rolt Kenneth D | Sound reinforcing seal for slotted acoustic transducers |
NO179654C (en) * | 1994-05-06 | 1996-11-20 | Unaco Systems Ab | Acoustic transmitter with sound-emitting surfaces adapted to vibrate motion |
NO301796B1 (en) * | 1995-05-18 | 1997-12-08 | Unaco Systems Ab | Drive unit for acoustic transmitters |
NO961765L (en) * | 1996-04-30 | 1997-10-31 | Unaco Systems Ab | Acoustic transmitter II |
US7136324B1 (en) * | 2004-10-28 | 2006-11-14 | The United States Of America As Represented By The Secretary Of The Navy | Pressure equalizing fluidborne sound projector |
US7633835B1 (en) * | 2006-03-27 | 2009-12-15 | Bae Systems Information And Electronic Systems Integration Inc. | High power, motor driven underwater acoustic transducer |
US9535180B2 (en) * | 2013-02-22 | 2017-01-03 | Cgg Services Sa | Method and system for pneumatic control for vibrator source element |
US9360574B2 (en) * | 2013-09-20 | 2016-06-07 | Pgs Geophysical As | Piston-type marine vibrators comprising a compliance chamber |
US9606252B2 (en) * | 2013-12-23 | 2017-03-28 | Pgs Geophysical As | Low-frequency magnetic reluctance marine seismic source |
-
2016
- 2016-08-23 WO PCT/US2016/048201 patent/WO2017035144A1/en active Application Filing
- 2016-08-23 EP EP16839990.5A patent/EP3341762A4/en not_active Withdrawn
Also Published As
Publication number | Publication date |
---|---|
EP3341762A4 (en) | 2019-07-10 |
WO2017035144A1 (en) | 2017-03-02 |
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