There is provided a DC-DC converter which converts an input voltage into an output voltage for supply to a load, in which an input terminal receives the input voltage, an output terminal outputs the output voltage, power stages each includes: a high side switch, a low side switch and an inductor, the control unit executes a first mode and a second mode wherein the first mode controls the high side switch and the low side switch in each of the power stages so that a ratio of an output current in each of the power stages to a load current flowing through the load becomes a set value and the second mode controls the high side switch and the low side switch in each of the power stages so that duty ratios of the high side switch and the low side switch are equalized among the power stages.

Embodiments of an aerodynamic structural insert frame comprise a leading edge, a trailing edge opposite the leading edge, and at least one cavity between the leading edge and trailing edge, wherein the aerodynamic structural insert frame is configured to deflect upon activation by an external stimulus; at least one deformable buckling member extending the distance between opposite edges of the cavity, wherein the deflection of the aerodynamic structural insert frame is configured to trigger deflection of the deformable buckling member; a pivot region; and at least one stopper bar attached to and extending from one edge of the cavity a distance less than the distance between opposite edges of the cavity, wherein the stopper bar is configured to stop the deflection of the aerodynamic structural insert and the buckling member when the stopper bar strikes an opposite edge of the cavity.

Systems and methods for performing airport surface collision-avoidance. A wingtip-mounted camera allows the pilot to positively ascertain that the wingtip will clear objects located in the video. An exemplary system implemented on an aircraft includes a wingtip module having a camera that generates a video stream and a communication device that transmits the generated video stream. A processor receives the video stream and generates a reticule for the video stream. A display device simultaneously presents the video stream and the reticule. The reticule includes a horizon line and is based on a focal length of a lens of the camera and height of the camera above ground. The reticule includes curved and/or straight distance lines and curved or straight travel lines. The travel line(s) correspond to at least one aircraft component or a zone of importance and are based on location of the camera and trajectory of the aircraft.

An unmanned, towable aerovehicle is described and includes a container to hold cargo, an autogyro assembly connected to the container and to provide flight characteristics, and a controller to control operation the autogyro assembly for unmanned flight. The container includes a connection to connect to a powered aircraft to provide forward motive force to power the autogyro assembly. In an example, the autogyro assembly includes a mast extending from the container, a rotatable hub on an end of the mast, and a plurality of blades connected to the hub for rotation to provide lift to the vehicle. In an example, an electrical motor rotates the blades prior to lift off to assist in take off. The electrical motor does not have enough power to sustain flight of the vehicle.

A passively torque-balanced device includes (a) a frame; (b) a drivetrain including a drive actuator mounted to the frame and configured for reciprocating displacement, an input platform configured for displacement by the drive actuator, a plurality of rigid links, including a proximate link and remote links, wherein the rigid links are collectively mounted to the frame, and a plurality of joints joining the rigid links and providing a plurality of non-fully actuated degrees of freedom for displacement of the rigid links, the plurality of joints including a fulcrum joint that is joined both to the input platform and to the proximate rigid link; and (c) at least two end effectors respectively coupled with the remote links and configured for displacement without full actuation.

A system has a plurality of spacecraft in orbit around the earth for collecting energy from the Sun in space, using stimulated emission to configure that energy as well defined states of the optical field and delivering that energy efficiently throughout the region of space surrounding Earth.

A method for simulating the movement behavior of a fluid in a closed moving container is provided. The simulation is based on the determination of the potential movement path of the center of gravity of the volume of the fluid as an elliptical trajectory situated in a disturbance plane having certain semi-axes.

A stator for a progressive cavity pump comprises a stator housing having a central axis, a first end, and a second end opposite the first end. In addition, the stator comprises a stator liner disposed within the stator housing. The stator liner has a first end and a second end opposite the first end. The first end of the stator liner is axially spaced from the first end of the stator housing. Further, the stator comprises a tag insert positioned in the stator housing between the first end of the stator housing and the first end of the stator liner. The tag insert has a through passage defining a radially inner surface that includes a tag shoulder.

A casing window assembly for completion of a lateral wellbore. The casing window assembly includes a tubular casing sleeve with a casing window and an inner sleeve releasably secured within the casing sleeve at a pre-released position adjacent the casing window.

Use of two different methods, either each by itself or in combination, to enhance the stiffness, strength, maximum possible use temperature, and environmental resistance of thermoset polymer particles is disclosed. One method is the application of post-polymerization process steps (and especially heat treatment) to advance the curing reaction and to thus obtain a more densely crosslinked polymer network. The other method is the incorporation of nanofillers, resulting in a heterogeneous “nanocomposite” morphology. Nanofiller incorporation and post-polymerization heat treatment can also be combined to obtain the benefits of both methods simultaneously. The present invention relates to the development of thermoset nanocomposite particles. Optional further improvement of the heat resistance and environmental resistance of said particles via post-polymerization heat treatment; processes for the manufacture of said particles; and use of said particles in the construction, drilling, completion and/or fracture stimulation of oil and natural gas wells are described.

Fluid treatment systems and compositions are provided including (a) at least one material including (1) at least one carboxylic acid functional group and (2) at least one sulfur-containing group selected from the group consisting of sulfonyl functional groups, sulfonate functional groups and mixtures thereof; and (b) at least one friction reducing agent selected from the group consisting of guar gums, polyacrylamides, hydratable cellulosic materials, viscoelastic surfactants, and mixtures thereof. The fluid treatment systems and compositions can be used to treat aqueous systems, for example as fracturing fluids for use in fracturing subterranean formations. Methods for inhibiting formation and/or precipitation of metal oxides in an aqueous composition using the fluid treatment systems or compositions also are provided.

Fluid treatment systems and compositions are provided including (a) at least one material including (1) at least one carboxylic acid functional group and (2) at least one sulfur-containing group selected from the group consisting of sulfonyl functional groups, sulfonate functional groups and mixtures thereof; and (b) at least one scale control agent. The fluid treatment systems and compositions can be used to treat aqueous systems, for example as fracturing fluids for treating aqueous compositions found in subterranean formations. Methods for inhibiting formation and/or precipitation of calcium salts in an aqueous composition using the fluid treatment systems or compositions also are provided.

A shaped charge casing cutter is constructed with the cutter explosive formed into radial section modules aligned in a toroidal cavity between a pair of housing plates. The center sections of the plates are contiguously aligned with opposite parallel surfaces of a center disc. The plate rims are offset from respective center disc planes in opposite directions from each other to form a toroidal cavity. The toroidal cavity is enclosed by a circumferential belt secured to said plate rims. V-grooved shaped charge explosive in the form of multiple pi sections is distributed about the cavity to intimately contact a pair of frusto-conical liners.

A pourable aqueous cement composition is disclosed. The cement composition comprises a hydraulic cement, water and a selectively removable material comprising a plurality of selectively corrodible metal powder particles dispersed within the cement or a nanomatrix powder compact, or a combination thereof. An article, including a downhole article, and more particularly a reconfigurable downhole article is disclosed. The article includes a hydraulic cement, wherein the hydraulic cement has at least partially set into a permanent form. The article also includes a selectively removable material dispersed within the cement, the selectively removable material comprising a plurality of selectively corrodible metal powder particles dispersed within the cement or a nanomatrix powder compact, or a combination thereof, wherein the selectively removable material is configured for removal in response to a predetermined wellbore condition.

In an embodiment, the cement compositions comprise: (i) hydraulic cement, wherein the hydraulic cement has a ratio of CaO to SiO2 in the range of 2.0 to 4.0; and (ii) a water-soluble metaphosphate in a concentration of at least 2.5% bwoc. In another embodiment, the cement compositions comprise: (i) hydraulic cement, wherein the hydraulic cement has a ratio of CaO to SiO2 of less than 2.0; and (ii) a water-soluble metaphosphate; wherein any alkali nitrate is in a concentration of less than 2% bwoc; and wherein any alkali hydroxide, alkali carbonate, or alkali citrate is in a concentration of less than 0.2% bwoc. Methods of cementing in a well comprising forming either of such cement compositions and introducing it into the well are provided.

An oxygen scavenger for completion brines effective and stable in high temperature subterranean formations. In one embodiment, the scavenger contains erythorbate and alkylhydroxlyamine.

A system for diverting fluids from a wellhead in a subsea environment has a capping stack with a connector suitable for connection or interconnection to the wellhead, a flow base fixedly positioned in the subsea environment, and a conduit connected to the outlet of a diverter line of the capping stack and connected to the inlet of an interior passageway of the flow base. The conduit is suitable for passing fluids from the capping stack toward the flow base. The flow base is a modified horizontal Christmas tree. The interior passageway within the horizontal Christmas tree has a plug therein located a level below the level of the inlet to the flow base. The flow base can be attached to a wellhead or to an anchor pile in the subsea environment.

A centralizer comprises a first body portion, a second body portion, a plurality of bow springs connecting the first body portion to the second body portion, and one or more expandable elements coupled to the first body portion and the second body portion. A method of centralizing a wellbore tubular comprises compressing a bow spring radially inward from a starting position to a compressed position, wherein the bow spring is coupled to a first body portion and a second body portion, applying a tensile force between the first body portion and the second body portion while the bow spring is in the compressed position, and restoring the bow spring from the compressed position to the starting position.

A method for determining position of a wellbore in the Earth's subsurface includes actuating a plurality of seismic energy sources each disposed at a known geodetic position. Seismic energy from the sources is detected at a selected location along the wellbore. The geodetic position at the selected location is determined from the detected seismic energy. A corresponding method includes actuating a seismic energy source at a selected position within the wellbore. The seismic energy is detected at a plurality of known geodetic positions. The geodetic position of the source is determined from the detected seismic energy.

Magnetic composite particles can be used as proppants and allow for deliberate heating by applying an alternating magnetic field.

A technique includes processing seismic data indicative of samples of at least one measured seismic signal in a processor-based machine to, in an iterative process, determine basis functions, which represent a constructed seismic signal. The technique includes in each iteration of the iterative process, selecting another basis function of the plurality of basis functions. The selecting includes based at least in part on the samples and a current version of the constructed seismic signal, determining a cost function; and interpreting the cost function based at least in part on a predicted energy distribution of the constructed seismic signal to select the basis function.

A method for selective removal and recovery of silica and silicon containing compounds from solutions that include silica and silicon containing compounds, including geothermal brines. Also included are methods of preventing silica scale buildup in the geothermal power equipment and processes employing geothermal brines by the selective removal of silica.

When conducting cementing operations within confined locales, such as the annular space within a wellbore, it can sometimes be difficult to successfully deliver an uncured cement composition to a desired location. Cementing methods can comprise: providing a cement composition comprising a cement and a property control package, the property control package comprising: a filtration control agent; a friction reducer; and a setting accelerator; introducing the cement composition into a mineral exploration wellbore; and setting the cement composition in the wellbore.

A steam assisted gravity drainage process that includes the addition of oxygen for recovering hydrocarbons from a hydrocarbon reservoir is described. Steam and an oxygen-containing gas are separately and continuously injected into the hydrocarbon reservoir to heat hydrocarbons and water to drain, by gravity, to a horizontal production well. The process can include controlling the ratio of oxygen and steam from about 0.05 to about 1.00 (v/v). The steam assisted gravity drainage process can further include removing non-condensable combustion gases from the reservoir to avoid undesirable pressures in the reservoir. The non-condensable combustion gases can be removed from the reservoir by at least one separate vent-gas well.

A method of treating sludge using solar energy is provided. The present invention utilizes a Fresnel panel frame that includes at least one Fresnel panel. The Fresnel panel may cover at least a portion of a bed cavity. An amount of waste may be placed within the bed cavity. When placed in sunlight, the heat enhanced by the Fresnel panels may heat the waste sufficiently for safe easy disposal, recycling, or for the creation of fertilizer.

There are provided a dividing wall distillation column for producing high-purity acrylic acid, and a fractional distillation method using the same. The dividing wall distillation column includes a condenser, a reboiler and a main column having a dividing wall. Here, the main column is divided into a column-top zone, an upper feed zone, an upper outflow zone, a lower feed zone, a lower outflow zone and a column-bottom zone. Accordingly, since one distillation column can be used to realize the same effect as that obtained from the use of two distillation columns, the dividing wall distillation column can have an effect of reducing the costs of equipment to produce high-purity acrylic acid, as well as an energy-reducing effect, compared to a conventional process system.

A method for creating laboratory-scale reactive distillation apparatus from provided modular components is described. At least two types of modular distillation column stages are provided. A first type of modular stage comprises two physical interfaces for connection with a respective physical interface of another modular stage. A second type modular stage comprises one such physical interface. At least one type of tray is provided for insertion into the first type of modular stage. A clamping arrangement is provided for joining together two modular stages at their respective physical interfaces for connection to form a joint. The invention provides for at least three modular stages can be joined. At least one sensor or sensor array can be inserted into each modular stage. At least one controllable element can be inserted into each modular stage. The invention provides for study of traditional, advanced, and photochemical types of reactive distillation.

An electrical heating coal material decomposition apparatus includes a closed kiln body with a feed inlet, a discharge outlet, and an electrical heating device arranged in the kiln body. A propulsion and decomposition path of coal material is formed between the electrical heating device and the inner wall of the kiln body. A coal decomposition gas collecting pipe communicates with the propulsion and decomposition path of coal material, and is connected with a gas dust-trapping and liquefying device arranged outside the kiln. The electrical heating device transfers heat to the pulverized coal inside the propulsion and decomposition path of coal material by conduction and irradiation. The pulverized coal absorbs sufficient heat and decomposes into fuel gas, tar gas and coal. The fuel gas and tar gas enters the gas dust-trapping and liquefying mechanism through the decomposed gas collecting tube, where they are collected, dust-trapped, separated and liquefied under pressure.

A method of removing organic components from a mixture containing organic and inorganic components which method involves providing an induction heated screw conveyor having an auger and passing the mixture through the induction heated screw conveyor while inductively heating the auger so as to heat the mixture in the induction heated screw conveyor primarily from the center of the induction heated screw conveyor. The mixture is heated to a temperature that is sufficient to cause the organic components in the mixture to separate from the mixture as a vapor. The oxygen concentration in the induction heated screw conveyor is controlled so as to gasify the organic components. The gasified organic components are removed and the remaining inorganic components are collected.

A process for the physical refining of edible oils and fats, said process comprising three consecutive stages, whereby in a first stage at least 60% by weight of the volatiles are evaporated in a flash vessel, in a second stage some residual volatiles are evaporated by countercurrent steam stripping using a packed column (3), and in a third stage further residual volatiles are evaporated in a cross-flow tray system (2), wherein the pressure in said flash vessel is maintained at a value below the pressure prevailing above said packed column (3); and an apparatus for the physical refining of edible oils and fats comprising a flash vessel, a packed column (3), sparging trays (2) and the means to maintain the pressure in said flash vessel at a value that is below the pressure prevailing above said packed column.

An improved rapid thermal conversion process for efficiently converting wood, other biomass materials, and other carbonaceous feedstock (including hydrocarbons) into high yields of valuable liquid product, e.g., bio-oil, on a large scale production, is disclosed. In the process, biomass material, e.g., wood, is fed to a conversion system where the biomass material is mixed with an upward stream of hot heat carriers, e.g., sand, that thermally convert the biomass into a hot vapor stream. The hot vapor stream is rapidly quenched with quench media in one or more condensing chambers located downstream of the conversion system. The rapid quenching condenses the vapor stream into liquid product, which is collected from the condensing chambers as a valuable liquid product.

A trihalosilane refining device and a trihalosilane refining method are provided. The trihalosilane refining device can be useful in obtaining high-purity trihalosilane from a feed containing a trihalosilane while consuming a small amount of energy.

A trihalosilane refining device and a trihalosilane refining method are provided. The trihalosilane refining device can be useful in obtaining high-purity trihalosilane from a feed containing a trihalosilane while consuming a small amount of energy.

Mechanical visbreaking and pyrolysis between counter-rotating coaxial centrifugal impellers in a continuous radial counterflow process minimizes wastewater discharges. In one example, a cataclastic shear retort comminutes, shear thins, and shear heats an axial feed, such as tar sand, oil shale, coal tailings, distillation bottoms, or lignite. Pyrolyzing the feedstock in this shear retort yields a product stream of gases, naphthas, and oils which first mixes with the feedstock and then is axially extracted, while spent solids are simultaneously extruded from the periphery as coked devolatilized residue, such as char sand for upgrading soil to terra preta. Recirculation of shear-heated solids in long residence time within the shear retort brings heat from the spent solids at the periphery to the feedstock without an external heated sand loop. CO2 emissions from combustion to heat water for oil extraction are eliminated.

An evaporative desalination device includes a multi stage vapor generator that generates vapor by passing a hot water supply pipe successively through a plurality of vapor generators to evaporate sea water inside thereof, a multi effect vapor generator that uses vapor in the respective vapor generators as heat source and forms a plurality of evaporator groups which can adjust a number of evaporators disposed inside the respective evaporator groups and produce fresh water according to amounts of supplied vapor to evaporate sea water in the evaporator groups on an outer circumference surface of an evaporation tube by heat of vapor flowing in the evaporation tube, and a discharge unit that condenses vapor in the multi effect generator by sea water to discharge fresh water in liquid state, and returns and supplies portions of discharged sea water to the multi stage vapor generator and the multi effect evaporator.

A device (1) comprises a source (20) for emitting ultraviolet light, an inlet (30) for letting in fluid to the device (1), an outlet (40) for letting out fluid from the device (1), and means (51, 52) for performing a straightening action of a flow of fluid through the device (1). The flow straightening means comprise at least one flow straightening element (51, 52) having inlet openings for letting in fluid at one side and outlet openings for letting out fluid at another side, wherein each inlet opening is in communication with a plurality of outlet openings, and wherein the element (51, 52) comprises a maze of randomly arranged, interconnected holes. In such a structure, a water element that is moving from one side of the element (51, 52) to another side may take one of various paths, as a result of which variations in inlet conditions can be dampened.

A tensioning assembly having a drive pulley, a tension pulley and a tension adjustment system is provided. The drive pulley has a first drive pulley channel and a second drive pulley channel. The tension pulley has a first tension pulley channel and a second tension pulley channel. The second tension pulley channel is aligned with the first drive pulley channel. The first drive pulley channel and the second drive pulley channel of the drive pulley and the first tension pulley channel and a second tension pulley channel of the tension pulley are configured and arranged to engage and route an endless looped member. The tension adjustment system is coupled to adjust the distance between the drive pulley and the tension pulley to adjust the tension in the endless looped member in relation to the drive pulley.

A hoist spooling assembly for spooling a cable about a drum while preventing relative movement between the cable and the drum. The hoist spooling assembly evenly delivers force from a roller to the cable while reducing the incidence of spooling problems, including mechanical wear of the cable and formation of loops and kinks in the cable.

A load sensitive magnetic clutch device includes: a magnetic pole rotating body having magnetic poles arranged on the circumference thereof and provided with a clutch projection of a claw clutch at an end thereof; a yoke rotating body configured to rotate about an axial center of rotation identical to that of the magnetic pole rotating body; and a high-torque input member configured to rotate about the identical axial center of rotation and having a clutch engaging portion engaging the clutch projection. The clutch projection is formed of a magnetic body. The clutch engaging portion includes a clutch retaining magnetic body configured to attract the clutch projection by a magnetic force. The clutch projection is attracted by the clutch retaining magnetic body by an application of a load torque exceeding a torque which is transferrable between the magnetic pole rotating body and the yoke rotating body.

A manual marine winch includes a safety knockout override preventing release of winch tension without the handle in stowed position. The winch includes a housing; a rotating drum on the housing; a winch line on the drum; a control for spooling and un-spooling the winch line on the drum, wherein the control includes a handle for selectively tensioning the drum and moveable between a position engaged with the drum and a disengaged stowed position; a tension holding mechanism on the housing comprising a ratchet gear coupled to the drum, a pawl selectively engaged with the ratchet gear, and a knockout configures to selectively disengage the pawl from the gear to allow for release of winch tension; and a safety knockout override coupled to the housing and selectively engaged by the handle and configured to prevent release of winch tension when the handle is not in the stowed position.

A height adjusting device for a vehicle suspension seat includes: a control valve having an air injection pin and an air discharge pin formed therein; a first push support having one end rotatably coupled to the control valve and pressurizing the air injection pin when rotated in one direction; a second push support having one end rotatably coupled to the control vale, pressurizing the air discharge pin when rotated in one direction, and disposed to correspond to the first push support; a first push rod pressurizing the other end of the first push support so as to rotate the first push support; and a second push rod pressurizing the other end of the second push support so as to rotate the second push support, and disposed to correspond to the first push rod.

A three dimensional wire flying system includes a plurality of winches collectively hanging an object and a control unit for controlling the plurality of winches and the main safety device. Each of the plurality of winches includes a drum unit, a wire wound on the drum unit, a motor unit which provides power to the drum unit, a brake module which stops rotation of the drum unit, a limit switch which operates upon detecting a hardware limit state, and a servo-system. Each of the plurality of winches operates to move the object in a three dimensional space in three directions, including an up-down direction, a left-right direction and a forward-backward direction, and each winch provides a multi-level safety protection.

A load sensing transmission device in which when a rotation is transmitted to a sun gear, and planetary gears are rotated, if the rotation of an internally-toothed ring gear disposed at an outer circumference of the planetary gears is restricted in at least one direction, a decelerated rotation is output from a planetary carrier by revolution of the planetary gears. When the internally-toothed ring gear is rotated without being restricted, and simultaneously rotated together with the revolution of the planetary gears the rotation which is not decelerated is output from the planetary carrier. Existence and non-existence of the restriction of the rotation of the internally-toothed ring gear are switched by sensing a load by the load sensing mechanism and performing the engagement and disengagement by an engagement pawl. The rotation of the planetary carrier is output through a plate with slider, load springs, and a plate with cam.

An assembly for collapsing a self-expanding prosthetic heart valve includes a compression member, a support member and a constricting member. The compression member has a tapered wall between its first open end and its second open end, the tapered wall defining an open space adapted to receive the valve. The support member has a base and a recess adapted to receive an end of the valve. The support member and the compression member are movable toward one another to compress the valve and push it through a relatively small aperture in the second open end of the compression member. The second end of the constricting member is sized to receive the compressed valve from the second open end of the compression member for loading into a delivery device.

An extension has a main extension body with a first extension end and a second extension end, an extension passage is defined there between. An annular extension recess is formed about the extension passage at the first extension end. An annular extension flange is formed about the extension passage at the second extension end. A saddle has a main saddle body with a first saddle end and a second saddle end with a saddle passage defined there between. An annular saddle flange is formed about the saddle passage at the second saddle end. A fastener has an elongate shaft with a first shaft end and a second shaft end. A head is at the first shaft end. A fastening engagement is about the second shaft end. The shaft is configured to be disposed within the saddle passage and the extension passage.

The present invention describes a hair treatment application system, comprising at least one or more hair treatment compositions (15) having a viscosity of from 3,000 cPs to 150,000 cPs and a hair treatment application device (1) comprising a first plate (10) and a second plate (20) positionable in a juxtaposed relationship when said hair treatment application device (1) is in a closed state. The hair treatment application device (1) is characterized by having a first zone comprising at least one absorbent substrate (40) on the internal surface (101) of said at least said first plates (10) and a second zone (50) on said internal surface (101) which is free of said absorbent substrate (40). Said at least one absorbent substrate (40) has a median pore radius of from 300 microns to 3,000 micron. The present invention describes also methods of treating the hair with said hair treatment application system (10) and kit comprising said hair treatment application system.

A disclosed decorative device includes an elongate, flexible foam body, an elongate, pliable core element, a pair of adapters, and a pair of end pieces. A method for making the decorative device is described, as is a method for retaining hair using the decorative device. The decorative device includes the elongate, flexible foam body surrounding the elongate, pliable core element along its length. The pair of adapters are each configured to fixably receive an end of the elongate, pliable core element, with the pair of end pieces, each being configured to connect to one of the pair of adapters.

A nail print apparatus, including: a print head which performs printing on a nail region on the basis of image data including a first design and a second design that is a background of the first design; and an image data processing unit which has a second image data processing unit that processes the image data so that the second design covers an entire nail region.

Compositions for application and methods of application of a composition to modify hair. In one embodiment, a composition includes a compound (molecule) represented by: wherein A and B are individually selected from a hydrogen, a hydroxyl group and a halogen, with the proviso that when one of A and B is a hydroxyl group, the other of A and B is a hydrogen and when one of A and B is a halogen, the other of A and B is a halogen or a hydrogen;wherein Z is, for example, an aryl moiety; andwherein X1 and X2 are, for example, individually selected from a hydrogen and an alkyl moiety,wherein R1 and R2 are individually selected from an oxo, a hydroxyl or an ester group;wherein y is 0 or 1, x is 0 or 1 and x and y are not both 1, or a salt.

A hair clip having a rectangular base frame, with a plurality of prongs forming a unitary structure with the base frame, is disclosed. A weft clip frame is fixedly attached to, or forms a unitary structure with, the base frame. The weft clips which are attached thereto form a U-shape with a portion of said U-shape on either side of the rectangular base frame and extend over an uppermost extremity of the rectangular base, while the lower end of the rectangular base has openings of prongs for attaching hair thereto. The weft clips, in embodiments, hold the weft of a hair extension between the weft clip and rectangular base, such as in a portal of the weft clip opening only towards the top of the rectangular base.