A wind turbine with a tower; a nacelle supported by said tower; at least one unit to be cooled and arranged in the tower or the nacelle; a tower mounted heat exchange structure arranged outside the nacelle and tower; and a circuit facilitating a flow of a fluid medium between the at least one unit and the heat exchange structure. To improve thermal convection with the ambient space, the heat exchange structure comprises a set of panels mutually angled and extending outwards from the tower such that a flow of ambient air can pass transversely trough the panels and thereby cool the unit.

A heat exchanger for a battery has fluid-carrying panels and defines a multi-sided enclosure for enclosing at least two sides of the battery. The heat exchanger has first and second fluid-carrying panels defining first and second flow channels, where the first and second fluid-carrying panels are arranged at an angle to another. The heat exchanger may also include a third fluid-carrying panel defining a third flow channel, and being arranged at an angle to the second fluid-carrying panel. The heat exchanger has first and second plates sealingly joined together along their peripheries and defining a fluid flow passageway between their central fluid flow areas. The second plate may be compliant, its central fluid flow area being deformable away from the central fluid flow area of the first plate in response to a pressure of a fluid inside the fluid flow passageway.

The present document discloses a plate type heat exchanger for an oil cooler, comprising at least two heat exchanger members, each enclosing a respective first cavity (C1), at least one inlet port (20, 22), for feeding a medium to the first cavities and at least one output port (21, 23) for extracting the medium from the first cavities (C1); and at least one mounting member (13, 14), which is attached to an outside of an outermost one, as seen in a stacking direction (Z), of the heat exchanger members. A second cavity (C2) is formed between the at least two heat exchanger members. A medium present in the second cavity (C2) is isolated from a medium present in the first cavities (C1). A reinforcement plate (30, 31) is located on an inside of the outermost one of the heat exchanger members, and at least partially overlapping the mounting member (13, 14).

A heat exchanger system comprises a first heat exchanger, a second heat exchanger, a mixer, and a third heat exchanger. A first working fluid flow path connects the first working fluid outlet port and the first mixer inlet port, a second working fluid flow path connects the second working fluid outlet port and the second mixer inlet port, and a third working fluid flow path connects the mixer outlet and the third inlet port.

Heat sinks having a mounting surface with a coefficient of thermal expansion matching that of silicon are disclosed. Heat pipes having layered composite or integral composite low coefficient of expansion heat sinks are disclosed that can be mounted directly to silicon semiconductor devices.

A heat sink adapted to dissipate heat from a heat source includes a heat dissipating unit that includes at least one deformation portion protruding toward the heat source, and a reflective surface formed on the deformation portion and facing the heat source for reflecting radiant heat from the heat source. A case including the heat sink is also disclosed.

A heat transfer system includes a substrate having a heat exchange region including a surface having an enhancement region including alternating regions of selectively placed plurality of nucleation sites and regions lacking selectively placed nucleation sites, such that bubble formation and departure during boiling of a liquid in contact with the enhancement region induces liquid motion over the surface of the regions lacking selectively placed nucleation sites sufficient to enhance both critical heat flux and heat transfer coefficient at the critical heat flux in the enhancement region of the system.

A heat dissipation module adapted to perform heat dissipation on a heat generating component is provided. The heat dissipation module includes a graphite sheet and an insulating and heat conducting layer. The graphite sheet includes a plurality of through holes, an attaching surface and a heat dissipating surface opposite to the attaching surface, wherein the attaching surface is configured to be attached to the heat generating component. Each of the through holes penetrates the graphite sheet, so the attaching surface and the heat dissipating surface are connected via the through holes. The insulating and heat conducting layer covers the graphite sheet. The insulating and heat conducting layer least covers the attaching surface, the heat dissipating surface and inner walls of the through holes.

Provided are a heat recovery apparatus based on a fuel cell and an operating method thereof. In the fuel cell-based heat recovery apparatus and the operating method thereof, hot water and steam may be generated by using heat generated while a molten carbonate fuel cell (MCFC) operates to supply the generated hot water or steam to buildings, thereby reducing a rate of operation in cooling/heating equipment using electricity so as to reduce air-conditioning costs.

A swing structure of a heat dissipating device includes an elongated blade and a magnetic actuation disposed on the blade. The blade has a loading segment and a heat dissipating segment, two opposite end portions of the loading segment are respectively defined as a mounting end portion and a connecting end portion, and two opposite end portions of the heat dissipating segment are respectively defined as a positioning end portion and a free end portion. The connecting end portion is connected to the positioning end portion. A thickness of the loading segment is greater than that of the heat dissipating segment. When the magnetic actuation is driven by a magnetic field to swing the blade, a swing angle of the free end portion of the heat dissipating segment is greater than that of the connecting end portion of the loading segment.

A liquid-cooling heat sink has a heat-conductive tube and multiple heat-conductive units arranged adjacent to the heat-conductive tube. The heat-conductive tube has a first tube and a second tube. An isolation member having an isolation channel is located between the first tube and the second tube. The isolation member obstructs the heat exchange between the first tube and the second tube. A first delivery tube and a second delivery tube of each one of the heat-conductive bodies respectively connect to the first tube and the second tube of the heat-conductive tube, thereby integrating the first tube and the second tube and obstructing the heat exchange between the cooling liquids with different temperatures. Each of the heat-conductive units distributes the cooling liquids with different temperatures by the heat-conductive tube, thereby simplifying the pipeline setting and reducing the volume of the liquid-cooling heat sink.

A Rack Information Handling System (RIHS) has a liquid cooling subsystem that provides cooling liquid to liquid cooled (LC) nodes received in chassis-receiving bays of a rack. Leak collection structures are positioned to receive cooling liquid that leaks from the liquid cooling subsystem. Liquid sensors detect a presence of leaked cooling liquid in the leak collection structures. A leak detection subsystem responds to a detected presence of liquid by providing a leak indication. In one or more embodiments, the liquid cooling subsystem has a liquid rail formed by more than one rack interconnections vertically aligned in a rear section of the rack that are connected by modular rail conduits for node-to-node fluid transfer. The leak collection structures include a pipe cover received over at least one modular rail conduit. A liquid cavity of each pipe cover spills over into another lower pipe cover at a rate that can be correlated to severity of the leak.

A heat sink includes a cooling module and an installing assembly for fixing the heat sink on a housing. The installing assembly includes a case, a handle rotatablely fixed in the case and a support including a fixing board with blocks and two brackets. The handle is actively connected with the support. The fixing board is fixed on a bottom plate of the case. The handle includes two bulges. The brackets include two slide openings for receiving the bulges. When the heat sink is installed, the handle is rotated to be vertical, the bulges are out of the slide openings, and the blocks are stuck on the housing. When the heat sink is dismantled, the handle is rotated to be horizontal and the bulges are stuck into the slide openings to resist the brackets, thereof the fixing board being uplifted and the blocks being pushed away from the housing.

An air conditioning system of a motor vehicle with a refrigerant circuit for operation in a refrigerator mode and a heat pump mode. The refrigerant circuit includes a primary circuit with a compressor, a heat exchanger for heat transfer between the refrigerant and the surroundings, an expansion element and a heat exchanger for heat transfer from the intake air being conditioned for the passenger compartment to the refrigerant, and a first flow path. The flow path extends from a branching point between the compressor and the heat exchanger to an opening and includes a heat exchanger for heat transfer from the refrigerant to the intake air being conditioned for the passenger compartment. The heat exchanger is situated in a flow direction of intake air of the passenger compartment after the heat exchanger.

Disclosed is a heat exchanger including: a heat exchanger body; a gas inlet for introducing exhaust gas into the heat exchanger body; a coolant inlet for introducing a coolant into the heat exchanger body; a gas outlet for discharging the exhaust gas that is cooled by heat exchange with the coolant; and a coolant outlet for discharging the coolant that completes heat exchange with the exhaust gas. In this case, the heat exchanger body includes: a laminated tube core formed by laminating a plurality of gas channels side by side; a housing formed so as to enclose the laminated tube core except for opposite ends thereof; and a wave fin plate integrally provided with a plurality of wave fins and arranged within each of the gas channels, wherein each of the wave fins includes a fixed pitch section, and a variable pitch section.

What is disclosed is a heat exchanger including: a core including a plurality of core plates, first and second passages, and a vertical passage; a base plate including a passage port; and a distance plate; wherein the first vertical passage and the passage port are arranged apart from each other in a direction orthogonal to a stacking direction of the core plates, and wherein the distance plate includes a bottom wall part and a swelling part, the bottom wall part being a thin plate-shaped and being joined to an upper surface of the base plate, the swelling part swelling up in the stacking direction from the bottom wall part so as to surround a circumference of a communication passage which communicates the first vertical passage with the passage port and being joined to a lowermost surface of the core in a flange part of a tip of the swelling part.

A high-efficiency plate type heat exchanger increases a heat-exchanging efficiency with an exhaust gas by connecting unit fluidized beds formed with stacked heat exchanging plates to each other in up and down directions, and elongating a flow path of circulating water to be greater than or equal to two passes (2-PASS). The heat exchanger retrieves heat of an exhaust gas by increasing a flow amount of circulating water of a portion close to a burner while a circulation path is elongated as described above. In addition, the high-efficiency plate type heat exchanger increases efficiency thereof by inserting a baffle plate having distribution holes between unit fluidized beds, controlling a flow of an exhaust gas while reducing an exhaust speed of the exhaust gas using heat exchanging fins of the baffle plate, absorbing heat of the exhaust gas, and effectively using a heat transfer area.

A heat exchange device includes a housing, a heat exchange module, and a piezoelectric module. Isolated inner and outer circulation chambers are formed in the housing. The heat exchange module in the housing includes a stack of separated plates parallel to each other. An inner channel communicated with the inner circulation chamber and an outer channel communicated with the outer circulation chamber are defined respectively by both sides of one of the plates and the other adjacent plates. The piezoelectric module in the housing includes a piezoelectric chip, and first and second heat exchange sides thermally coupled to the piezoelectric chip. The first heat exchange side is located in the inner circulation chamber and the second heat exchange side is located in the outer circulation chamber, so that heat can be transferred between the inner and outer circulation chambers via the piezoelectric chip.

Various methods and systems are provided for cryogenic heat transfer by nanoporous surfaces. In one embodiment, among others, a system includes a cryogenic fluid in a flow path of the system; and a system component in the flow path that includes a nanoporous surface layer in contact with the cryogenic fluid. In another embodiment, a method includes providing a cryogenic fluid; and initiating chilldown of a cryogenic system by directing the cryogenic fluid across a nanoporous surface layer disposed on a surface of a system component.

An adjustable refrigerant distribution device and a heat exchanger having same. The heat exchanger comprises: first and second collecting pipes; a heat exchanger core body; and a refrigerant distribution device, the refrigerant distribution device comprises a first distribution pipe, a first inlet pipe and a first drive assembly. The pipe wall of the first distribution pipe is provided with a first distribution hole. The first distribution pipe is inserted into at least one of the first and the second collecting pipes. The first inlet pipe is located outside at least one collecting pipe and is in communication with the first distribution pipe, and the first drive assembly drives the first distribution pipe to move relative to at least one collecting pipe. The distribution pipe of the refrigerant distribution device and the heat exchanger can translate along the axial direction, thereby adjusting refrigerant distribution so as to satisfy different distribution requirements.

Integrated heat spreaders having electromagnetically-formed features, and semiconductor packages incorporating such integrated heat spreaders, are described. In an example, an integrated heat spreader includes a top plate flattened using an electromagnetic forming process. Methods of manufacturing integrated heat spreaders having electromagnetically-formed features are also described.

In a cooled component system, a heat exchanger mounted on a surface of the industrial component is housed in an isolated access compartment adjacent to but separated from the primary compartment containing the industrial component. Housing the heat exchanger in a separately accessible compartment permits access to the heat exchanger for cleaning or other purposes without having to shut down the industrial component being cooled. A means for moving a cooling media over the surface a the heat exchanger might also be included to maximize heat exchange.

The present invention aims to provide a technology capable of enhancing the effect of reducing differential data in size. A bit shift unit shifts either of old data and new data in a forward direction and a backward direction of its bit string by each of 0, 1, 2, . . . , and n bit(s) to generate a plurality of data. A copy bit string extracting unit extracts information on copy bit strings based on the plurality of data and other non-shifted data. An additional bit string extracting unit excludes copy bit strings from the new data to extract information on additional bit strings. A differential data generating unit creates differential data based on the information on copy bit strings and the information on additional bit strings.

The pulse width modulator includes a subtraction unit configured to perform subtraction between an m value digital signal and a pulse width modulation signal; a feedforward filter unit configured such that a ΔΣ modulator to which an output signal of the subtraction unit is input and which includes integrators of a second order or higher is in cascade connection, and configured to operate with a sampling frequency FS; a product-sum computing unit configured to operate with a sampling frequency (FS/n) (n: an integer of two or more) to perform product-sum computing of an output signal of each integrator of the feedforward filter unit; and a pulse width modulation unit configured to operate with the sampling frequency (FS/n) to perform pulse width modulation of an output signal of the product-sum computing unit to output a pulse width modulation signal.

Methods and systems for time interleaved analog-to-digital converter timing mismatch calibration and compensation may include receiving an analog signal on a chip, converting the analog signal to a digital signal utilizing a time interleaved analog-to-digital-converter (ADC), and reducing a blocker signal that is generated by timing offsets in the time interleaved ADC by estimating complex coupling coefficients between a desired digital output signal and the blocker signal utilizing a decorrelation algorithm on frequencies within a desired frequency bandwidth. The decorrelation algorithm may comprise a symmetric adaptive decorrelation algorithm. The received analog signal may be generated by a calibration tone generator on the chip. An aliased signal may be summed with an output signal from a multiplier. The complex coupling coefficients may be determined utilizing the decorrelation algorithm on the summed signals. A multiplier may be configured to cancel the blocker signal utilizing the determined complex coupling coefficients.

For analog-to-digital converters (ADCs) which utilize a feedback digital-to-analog converter (DAC) for conversion, the final analog output can be affected or distorted by errors of the feedback DAC. A digital measurement technique can be implemented to determine timing mismatch error for the feedback DAC in a continuous-time delta-sigma modulator (CTDSM) or in a continuous-time pipeline modulator. The methodology utilizes cross-correlation of each DAC unit elements (UEs) output to the entire modulator output to measure its timing mismatch error respectively. Specifically, the timing mismatch error is estimated using a ratio based on a peak value and a value for the next tap in the cross-correlation function. The obtained errors can be stored in a look-up table and fully corrected in digital domain or analog domain.

For analog-to-digital converters (ADCs) which utilize a feedback digital-to-analog converter (DAC) for conversion, the final analog output can be affected or distorted by errors of the feedback DAC. A digital measurement technique can be implemented to determine switching mismatch error for the feedback DAC in a continuous-time delta-sigma modulator (CTDSM) or in a continuous-time pipeline modulator. The methodology forces each DAC unit elements (UEs) to switch a certain amount times and then use the modulator itself to measure the errors caused by those switching activities respectively. The obtained errors can be stored in a look-up table and fully corrected in digital domain or analog domain.

Modifying a digital data stream that includes immediately consecutive code words of different length by segmenting, based on a certain block grid, the digital data stream. Each block of the block grid includes a fixed number of bits. It is determined whether all bits of the last block associated with the digital data stream are occupied by data of the digital data stream. If not all bits of the last block are occupied, the unoccupied bits of the last block are padded with bits of an end-of-record (EOR) indicator. If all bits of the last block are occupied, attaching an EOR indicator to the digital data stream is skipped.

A method of producing a surface-treated carbon black powder dispersion includes subjecting carbon black fine particles having a volume average particle size of 100 nm to 20 μm to wet granulation and drying by heating to obtain granulated carbon black having a hardness of 12 cN or less and a pH of less than 7, grinding the granulated carbon black to obtain a ground product having a volume average particle size of 20 nm to 20 μm, and subjecting the ground product to wet oxidization in an aqueous medium. The resulting surface-treated carbon black powder dispersion exhibits excellent print density, print quality, discharge stability, and storage stability when used as an inkjet printer aqueous black ink.

An application of carbon nanotubes on agglomerates of ore fines to increase the mechanical strength is provided. A process for the preparation of ore agglomerates having enhanced mechanical strength by the application of the carbon nanotubes is also provided.

A production saltwater disposal facility comprising a separator configured to receive production saltwater from a pipeline or a vehicle and separate hydrocarbons from the production saltwater, wherein the production saltwater received from the pipeline or vehicle is substantially the same composition as when the production saltwater was located in a subterranean formation, a hydrocarbon storage tank configured to receive hydrocarbons from the separator, a settling pit configured to receive the production saltwater from the separator and separate metals and/or other solids from the saltwater, an evaporator in fluid communication with the settling pit and comprising a nozzle configured to emit a stream of the saltwater along a path in air such that water in the saltwater evaporates, and a collection pit positioned under the path and configured to collect the salt from the saltwater after the water has evaporated.

More than a month since officials closed schools due to Covid-19, California leaders said a two-week blitz led by First Partner Jennifer Siebel Newsom has brought in 70,000 computers and other devices that will be distributed to needy students this week. Gov. Gavin Newsom has stressed the importance of distance learning and education multiple times during the past month—even talking about helping his own children with school work.…

Prepare for a May Day like no other. When Bay Area counties imposed stay-at-home orders to limit the COVID-19 epidemic, Richmond resident Blanca Retano lost her job as a parent educator at an elementary school. Her husband, a chef, had his hours cut to nine a week.…

A motor drive device is fixed to a wall part of a housing and comprises a duct having an inflow port and an outflow port of air. A main body part of the duct functions as a heat-sink unit which releases heat into the duct. The duct is arranged inside the housing. The inflow port and the outflow port are formed so that outside air can flow through openings formed in the wall part.

Methods and systems for using the Earth's magnetic field to power a machine having a motor, the system including a computer, a plurality of wires, a plurality of energy storing devices, all in controlled electrical communication with each other, wherein the plurality of wires can collect electrical energy from the Earth's magnetic field while the machine is put in motion by a power source powering the motor, wherein the collected electrical energy is stored in the plurality of energy storing devices or used to power the motor.

A device used to smooth a material's surface with abrasion. More specifically, the device is in the form of a glove or mitten with an abrasive layer that is placed over, and secured on, a user's hand to protect the user's hand and to provide an agile and flexible range of motion while sanding a material's surface.

A sweatband for use on the hand and wrist is provided. The sweatband provides a surface on the back of a user's hand which may be utilized by a person to wipe sweat or perspiration. Thus, the back of the hand (opisthenar or dorsal surface of the hand) is used when wiping perspiration. The sweatband is constructed such that a first band portion wraps around a user's wrist and a second band portion wraps around the palm and back portion of a user's hand. In one embodiment the sweatband may be constructed of an elongated piece of material that is looped to form the first and second band portions. In one embodiment, a sweatband is interchangeable for use with the left or right hand. In one embodiment the sweatband is reversible.

Provided is activewear with hidden pockets. More particularly, athletic garments such as pants comprising one or more waistband pocket, preferably concealable, are included. In embodiments, athletic garments with an interior concealed pocket in the fold-over portion of a fold down waistband are provided. The waistband pocket enables the wearer to store items such as car keys, hotel room keys and/or smart phones relatively inconspicuously and securely in the waistband of the garment. A purpose of the concealment includes minimizing attention from the items stored within the pocket and allowing the wearer to participate in a variety of athletic sports or events while carrying personal items in a secure manner. Preferred embodiments include athletic pants comprising (i) a fold down waistband, (ii) an annular storage pocket capable of retaining items without any additional material added to the pant, and (iii) one or more slits for the opening for the pocket.

Protective gear is provided, such as, for example, protective headgear that includes a rigid helmet structure, an engagement system configured to engage a user's head, and a plurality of tethering devices coupled between the engagement system and the rigid helmet structure to suspend the rigid helmet structure from the user's head when the protective headgear is worn. The protective headgear further includes at least one damper coupled to one or more of the plurality of tethering devices to resist motion of the rigid helmet structure relative to the engagement system when the rigid structure is impacted during an impact event.

Eye wear (10) that may be employed in the health industry. The eye wear (10) includes a shield (11) that is formed of a sheet of flexible material, such as plastic. A seal (19) is secured to a major face of the shield (11) and is formed of a strip of flexible plastics material such as foam, with the seal (19) extending beyond the shield (11) so as to provide the loops (23) that engage a user's ears to aid in securing the eye wear to the user's face.

A fabric assembly attachable to the front side of a men's underwear and a men's underwear having such a fabric assembly are described. The fabric assembly has layers of fabrics having linear slots perpendicular to each other so that the wearer can take his genital organ out through the intersection of the linear slots. The peripheries of the fabric layers are elastically stitched together to make a fabric assembly. The fabric layers have sufficient rigidity such that the linear slots do not open under the pressure of the genital organ, unless the wearer uses his hands to open the slots. The fabric assembly may also have a flap on the inside or outside of the fabric layers. One or two sides of the flap may be attached to the men's underwear and the other sides may not be attached to permit easy opening of the flap by hand.

Physical treatment garment for aiding in treatment and healing of injured or strained muscles. Garment is made of flexible material that can be pulled up around the waist, such as compression shorts or full length tights or leggings, and the garment has one or more pockets in the thigh and/or hamstring area to hold cold packs or heat packs and have a fastener apparatus at the top. The garment has fastening apparatuses on or about the hip area and on or about just above the knee. Using a flexible or compression wrap with the compatible fastening apparatuses, the compression wrap is wrapped around the leg and/or groin area and secured using the fastening apparatuses. Pockets for ice or heat treatment are similarly located in the front or rear of the tights or leggings with fastening connections to hold ice or heat packs for treatment of the applicable injury.

A footwear remover has a platform elevated above the ground, with one or more recesses in the platform for removing footwear. The platform provides sufficient surface area to allow a user to place an unshoed, clean foot away from where a soiled shoe was previously positioned. In one embodiment, the footwear remover may be mounted to a suspending surface and used as a drying and storage rack for footwear. The footwear remover may optionally include hanging features for drying and hanging accessory items.

Disclosed is a non-slip footwear which comprises a main body formed of a flexible material and formed to surround the sole of a foot of a user and to open the top side of the foot; toe insertion holes formed of the flexible material, protruding from the front part of the main body so that toes of the foot are respectively inserted into the toe insertion holes; an non-slip outsole formed at the heel part of the main body and formed of foamed rubber having abrasion resistance, and having a thickness of 1 mm˜5 mm; and non-slip dots formed at the sole part of the main body and the non-slip outsole.

This invention relates to a means of securing a lens member into a snow goggle frame member, wherein the goggle frame member includes first insertion apertures, with first locating blocks at front edge, the lens member has a lens secured thereon, the lens includes first troughs to receive a corresponding first block therein, a pair of first rails are formed at respective sides of the first trough, each first rail has a first notch which includes a pair of second notches thereat, retainers are secured to the goggle frame and lens frame respectively, one end of the first insertion aperture includes a first insertion post at one end and a first insertion section at the other end thereof to receive the first insertion post therein, the first insertion section is then inserted into the first notch. The goggle may be replaced with various lenses and secured firmly.

A protective garment including a heat, flame and abrasion resistant outer shell configured to be worn on at least part of a body of a wearer, the outer shell including an opening formed therein. The garment further includes a heat and flame resistant material, of a different type of material than the outer shell, positioned in the opening.

Drum pedal assemblies are disclosed which can include one or more adjustment features. Adjustment features which can be included in embodiments of the invention can include spring tension adjustment features, pedal incline adjustment features, lever length adjustment features, beater stem angle adjustment features, chain path adjustment features, operable chain length adjustment features, and chain connection point position adjustment features.

A method and system for teaching oneself to learn to play a string instrument and master it by analyzing one's real-time hand/finger movement/technique/form, enabling oneself to progress and correct one's own mistakes simultaneously. In one aspect, a system for learning to play a string instrument is provided that includes a simulation instrument that includes a plurality of strings, wherein at least one of the strings includes at least one-touch sensing sensor thereon in communication with at least one processor to receive a signal from the at least one touch-sensing sensor and determine therefrom when and where on the at least one string a user applies pressure to the at least one string.

A system 100, for determining the velocity of a hammer 120 of a keyboard instrument, with a light transceiver 140 and processing circuitry 160. The light transceiver 140 being configured to transmit a light signal to a hammer 120 to measure a hammer velocity, receive a reflected light signal from the hammer 120 indicative of the velocity of the hammer 120 and send an electrical signal to the processing circuitry 160, where the electrical signal is based on the reflected light signal from the hammer 120. The processing circuitry 160 being configured to receive and process the electrical signal so that a time interval between the electrical signal passing through a first trigger point and a second trigger point and the velocity of the hammer 120 can be determined.

A system for remotely generating sound from a musical instrument includes a linear exciter which may be configured as a brace for a sound board of the musical instrument. In one embodiment, the system includes an input configured to receive a signal representative of the sound of a first musical instrument, a linear exciter for converting the signal to mechanical vibrations, and a calibration system for altering the signal sent to the exciter.