Abstract: Aspects of the embodiments are directed to a microfluidic chip and methods of making the same. The microfluidic chip can include a sensor device residing on the microfluidic chip, the sensor-side comprising a chemical sensor and the backside including a backside electrode, the chemical sensor electrically coupled to the backside electrode by a via; a microfluidics channel in the microfluidic chip, the sensor-side of the sensor device facing the microfluidics channel; and a metal contact electrically connected to the backside electrode.

Abstract: The present technology provides for a microfluidic substrate configured to carry out PCR on a number of polynucleotide-containing samples in parallel. The substrate can be a single-layer substrate in a microfluidic cartridge. Also provided are a method of making a microfluidic cartridge comprising such a substrate. Still further disclosed are a microfluidic valve suitable for use in isolating a PCR chamber in a microfluidic substrate, and a method of making such a valve.

Abstract: A low-voltage microfluidic valve device and system for regulating the flow of fluid. One low-voltage microfluidic valve device for regulating the low of fluid includes a nano-textured dendritic metallic filament configured to grow and retract in response to a voltage. The low-voltage microfluidic valve device also includes a microfluidic channel configured to allow fluid flow, wherein the fluid flow is selectively interrupted by the growth of the nano-textured dendritic metallic filament. The low-voltage microfluidic valve device also includes a membrane positioned proximate to the fluid and configured to alter shape in response to the growth of the nano-textured dendritic metallic filament.

Abstract: Clog-resistant serpentine crossflow filters and blade loading structures for micro- and nano-fluidics are provided. In one aspect, a filter includes: a substrate; and at least one layer of pillars on the substrate, wherein the pillars are arranged adjacent to one another and groups of the pillars alternate between being perpendicular and parallel to a direction of fluid flow through the filter giving the filter a serpentine configuration having at least one downstream catch. A method of forming the filter as well as a system employing the filter in conjunction with a pillar sorting array and optionally a staged blade structure are also provided.

Abstract: A particle separation apparatus, according to an embodiment of the present invention, may comprise: a first input flow path into which a first fluid containing a plurality of particles of different sizes is introduced; a second input flow path into which a second fluid not containing particles is introduced; a connection flow path and the second input flow path so that a third fluid in which the first fluid and the second fluid are mixed movies; a plurality of discharge flow paths where the plurality of particles which come out through the other end of the connection flow path are separated and discharged according to the size of the particles; and a branch flow path where at least a part of the third fluid which comes out through the other end of the connection flow path is discharged.

Abstract: A system and method are provided for harvesting target biological substances. The system includes a substrate and a first and second channel formed in the substrate. The channels longitudinally extending substantially parallel to each other. A series of gaps extend from the first channel to the second channel to create a fluid communication path passing between a series of columns with the columns being longitudinally separated by a predetermined separation distance. The system also includes a first source configured to selectively introduce into the first channel a first biological composition at a first channel flow rate and a second source configured to selectively introduce into the second channel a second biological composition at a second channel flow rate. The sources are configured to create a differential between the first and second channel flow rates to generate physiological shear rates along the second channel that are bounded within a predetermined range.

Abstract: The combined value of integrating optical forces and electrokinetics allows for the pooled separation vectors of each to be applied, providing for separation based on combinations of features such as size, shape, refractive index, charge, charge distribution, charge mobility, permittivity, and deformability. The interplay of these separation vectors allow for the selective manipulation of analytes with a finer degree of variation. Embodiments include methods of method of separating particles in a microfluidic channel using a device comprising a microfluidic channel, a source of laser light focused by an optic into the microfluidic channel, and a source of electrical field operationally connected to the microfluidic channel via electrodes so that the laser light and the electrical field to act jointly on the particles in the microfluidic channel. Other devices and methods are disclosed.

Abstract: Methods and devices for concentrating target cells using dielectrophoresis (DEP) are disclosed. The method allows relatively high throughput of sample through a microfluidic device in order to allow rapid capture of target cells even when they are present in low concentrations within the sample. The method utilizes multiple chambers through which samples will flow, the chambers arranged such that the first capture area has a larger area and faster flow rate than a second chamber, the second chamber being positioned downstream of the first capture area and being smaller with a slower flow rate to further concentrate the material captured in the first capture area.

Abstract: An analytical system that includes a flow cell, a liquid delivery component, a gas delivery component and a bubble generator component, wherein the liquid delivery component is configured to deliver liquid from one or more reservoirs to the bubble generator component, wherein the gas delivery component is configured to deliver gas from one or more source to the bubble generator component, and wherein the bubble generator component is configured to mix liquids from the liquid delivery component with gas from the gas delivery component to deliver a fluid foam to the inside of the flow cell, wherein the fluid foam includes bubbles of the gas in the liquid.

Abstract: A method for handling, in a microfluidic system, microdrops which include samples, including the steps of forming, in an oil, microdrops of an aqueous solution containing a sample, the oil and/or the aqueous solution containing a sample including a gelling agent; trapping the microdrops by means of surface-tension traps pre-arranged in a trapping area; and at least partially gelling the oil in the trapping area and/or at least partially gelling the trapped microdrops.

Abstract: The present invention relates to the field of microfluidics and in particular to methods for detecting microfluidic droplets and particles within droplets, as well as sorting the droplets. These methods allow for quantifying properties and activities of the particles within the droplets. For this purpose, the invention provides microfluidic droplets comprising suitably labelled particles. The invention also provides microfluidic devices and systems having properties which make them particularly suitable for use in the methods of the invention.

Abstract: A scanning micro-fluid device for an exchange of species with a surface and with an intermediate immersion liquid is disclosed. The device comprises a first and a second micro-channel comprising a fluid. The first micro-channel comprises a first aperture and the second micro-channel comprises a second aperture. They have a distance to each other in an apex area in proximity of the surface of a substrate. The surface, the apex area is immersed with the intermediate immersion liquid. The device also comprises a first electrode reaching into the fluid on the first micro-channel and a second electrode reaching into the fluid on the second micro-channel, and an apex electrode. Different voltage levels are applicable to the first, the second and the apex electrode such that species are interacting at surface of the substrate.

Abstract: Provided is a container for PCR enabling cell observation and a PCR treatment with a single container. In the container for PCR, a bottom surface 17a of an inside is flat, a shape of the bottom surface is a circular shape or a polygonal shape with four or more sides, a size of the bottom surface 17a is large so that a diameter L of an approximated circle circumscribing the bottom surface 17a is 0.05 mm? or more and 1 mm? or less, and an angle of an angle ? on a side surface side formed between a side surface 17b adjacent to the bottom surface 17a and the bottom surface 17a is 50° or more and 80° or less.

Abstract: Devices, systems, methods, and kits are disclosed for amplifying small quantities of nucleic acid and identifying the nucleic acid sequences of the amplified nucleic acid products.

Abstract: Devices and methods for sample preparation via pressure cycling technology are disclosed. The device for sample preparation comprises a tube having an inner surface, a top, and a bottom, the tube configured to contain a sample at the bottom and to be received into a pressure chamber for sample preparation, a cap detachably connected to the top of the tube, and a tapered elongate member extending from the cap into the tube, the tapered elongate member configured to contact the inner surface of the tube and the sample in the bottom of the tube, wherein the tube is deformable such that in operation under pressure the tube is deformed against the tapered elongate member to promote disruption of the sample.

Abstract: The present invention relates to a microfluidic system including a temperature controller and a thermoplastic microfluidic chip that enables rapid PCR in a PCR chamber of the microfluidic chip. Thermal control of the PCR chamber is achieved by applying voltage to heater electrodes patterned directly onto one layer of the microfluidic chip. The temperature controller adjusts the voltage applied to the heater electrodes by changing temperature controller parameters selected to minimize duration of each PCR cycle. Furthermore, simple operation of the microfluidic chip is provided through using an integrated passive capillary valve, requiring minimum operator intervention and eliminating the need for fluidic interfacing, pumping, or metering during chip loading.

Abstract: A polymerase chain reaction (PCR) module is detachably combined with a reader system. The reader system includes a central processing unit (CPU) receiving a photo sensing signal to calculate gene amplification amount in real time and generating a temperature control signal based on a temperature signal and a temperature control information. The PCR module includes a photo sensor assembly, a partition wall, and an interface module. The photo sensor assembly includes a plurality of photo sensors and a temperature sensor. The photo sensors are arranged in an array shape to sense emission light generated from a specimen to generate the photo sensing signal. The partition wall is protruded from the photo sensor assembly to define a reaction space in which the specimen is received. The interface module is electrically connected to the photo sensor assembly to transmit the photo sensing signal and the temperature signal to the reader system.

Abstract: An analysis system and a method for testing a biological sample according to which, before the start of testing, the amount of energy remaining in an energy storage of the analysis device is compared with an energy requirement for the test, and the test is only started if the amount of energy meets the energy requirement, and/or a temperature-control apparatus designed for temperature-controlling the cartridge is controlled depending on an interior space temperature of the analysis device.

Abstract: A method for compressing or decompressing a spring loading a tie rod in a jaw crusher. The tie rod is supported by, at one location, a pendulum of the jaw crusher and, at another location, the jaw crusher's frame through the said spring. The spring is installed between the jaw crusher's frame and a second spring support supported by the tie rod; and the second spring support is moved in relation to the tie rod. A support part of the tightening device and at least two moving screws supported by the support part are arranged to influence the second spring support. The support part is supported by the tie rod through a locking member; and the at least two moving screws supported by the support part are moved to change the distance between the second spring support and the support part.

Abstract: A jaw crusher, a mineral material processing plant and a method for processing mineral material. The jaw crusher includes a fixed jaw and a movable jaw for forming a crushing chamber therebetween which is open at the top. The fixed jaw includes a first wear part mounted thereto and the movable jaw includes a pitman and a second wear part mounted thereto. The pitman is rotatably mounted to a first eccentric shaft. The pitman is further rotatably mounted to second eccentric shaft configured to guide the stroke of the movable jaw to create a movement pattern with a substantially linear crushing stroke, wherein the eccentricity of the second eccentric shaft is larger than that of the first eccentric shaft.

Abstract: A gyratory or cone crusher includes a measuring apparatus suitable for measuring load of the crusher, a first element placed on a main shaft of the crusher and a first detector suitable for detecting the first element which first detector provides a trigger starting a measurement revolution, and at least one second element placed on a drive shaft of the crusher and a second detector suitable for detecting the second element and providing a trigger corresponding to a certain rotational position of an inner blade of the crusher. The system includes an output to a screen for presenting the loads or averages of the loads corresponding to rotational positions of the inner blade of the crusher. Detections of the monitoring system can be used for controlling and monitoring a crushing event, such as by changing an area or a location of a feed opening of the crusher.

Abstract: A device for comminuting whole trees or brush type vegetation comprising a set of more than two rotatable substantially horizontally oriented comminution drum assemblies; said set of rotatable comminution drum assemblies being constructed and arranged in an angular orientation so that the uppermost rotatable comminution drum assembly in said set of more than two substantially horizontally oriented comminution drum assemblies first engages the top portion of the whole tree or brush type vegetation and the remaining rotatable comminution drum assemblies in said set of more than two substantially horizontally oriented comminution drum assemblies sequentially engage lower portions of the whole tree or brush type vegetation that exist immediately below the portions that are comminuted by each successive comminution drum assembly.

Abstract: A canola seed sample crusher features a frame, and a drum rotatably carried on the frame and having an array of seed pockets on an outer periphery thereof. The seed pockets are sized and shaped to receive individual canola seeds respectively therein. A pathway is arranged to receive a length of adhesive tape and guide the tape over the seed pockets in the outer periphery of the drum during rotation thereof to adhesively collect the sample of canola seeds from the seed pockets onto the adhesive tape. A crushing mechanism is carried on the frame and operatively installed at a position along the pathway to crush the sample of canola seeds collected on the adhesive tape during passage of the tap tape through the crushing mechanism.

Abstract: A proposal is made for a disposal apparatus for disposing of food leftovers. The disposal apparatus comprises at least one comminuter, which has at least one grinding chamber and at least one collecting chamber. The grinding chamber is connected to the collecting chamber via one or more openings. At least one comminuting device having at least one impact tool for comminuting the food leftovers is arranged in the grinding chamber. In addition, at least one mixing device for generating a movement in the food leftovers is arranged in the grinding chamber. A method for disposing of food leftovers is furthermore proposed.

Abstract: Discharge grate components for reducing machines including stops to inhibit pokers within the grate so that the pokers are not ejected from the grate with a high velocity.

Abstract: A mobile bulk material processing apparatus includes a main frame to support a material processing unit. A conveyor extends from the main frame and is mounted on a pivot joint to allow the conveyor to slew relative to the main frame, the pivot joint being positioned above the conveyor that is suspended below a region of the main frame.

Abstract: A system is disclosed. The system includes an impact processor comprising an inlet and an outlet, a secondary classifier comprising an inlet and an outlet, the secondary classifier being downstream of and coupled to the impact processor, a recirculation mixer valve downstream of and coupled to the outlet of the secondary classifier, and a recirculation line coupling the outlet of the first secondary classifier to the inlet of the impact processor.

Abstract: Detonable devices such as charged air bag inflators are fed to a shred tower at a controlled feed rate via a feed valve. Water spray and/or water baths in the shred tower prevent sparking and begin to solubilize chemicals while the inflators are fed to primary and optional secondary shredders respectively performing course and fine shreds. A sump receives the shredded material which continues solubilize and separate chemicals from metal. A conveyor lifts solids from the sump. Dewatered solids are fed to a receiving box for metal scrap recycling.

Abstract: A food processor includes a grinder to obtain a ground meat; a mixer to add fat to the ground meat; a payload bay to receive the ground meat; a plurality of evaporators coupled to the payload bay with a multiplicity of coolant tubes in each evaporator, wherein each tube enters and then exits the payload bay, further comprising one or more cryogenic valves coupled to the coolant tubes; a pump to force coolant flowing through the evaporators; and a processor with code for: chopping the ground meat and during chopping, adding salt and ice to the ground meat being chopped and adding liquid nitrogen to maintain the temperature of the meat being chopped below 5° C. to obtain a chopped meat product; adding fat to the chopped meat product and then chopping the fat and adding liquid nitrogen to maintain the temperature of the chopped meat product and fat being chopped between 1° C. and 10° C.

Abstract: A sorting station is provided with a hopper, at least one conveyor belt, a deck screener, including at least one mesh screen and at least one spray bar, a chute, having a tapering form, a prep screw, a dewatering screen, wherein the deck screener is configured to have vibration applied thereto to separate a matter from a mixture of matters, and where the at least one spray bar is configured to wash the mixture of matter and further separate a selected matter from the mixture of matters. Methods of sorting a particular matter from a mixture of matters, and processes of filtering soil are also provided.

Abstract: A cleaning device for cleaning an air-ionizing part of an electrode. The device comprises a cleaning member arranged to be in physical contact with the air-ionizing part of the electrode, the air-ionizing part of electrode and the cleaning member being arranged to slide relative to each other. The cleaning device further comprises an actuator arranged to activate the relative motion between the air-ionizing part of the electrode and the cleaning member. There is also provided an ionization electrode comprising the air-ionizing part and the cleaning device, as well as a ultrafine particle sensor, an air ionizer or an electrostatic air cleaner comprising such an electrode.

Abstract: Compositions including blends of one or more acrylamide/allyl thiourea polymer as a first depressant, and one or more carboxyalkyl dithiocarbamate compound as a second depressant, and their use as depressants in the beneficiation of sulfide minerals from ores and/or concentrates are disclosed herein, along with methods for selectively separating value sulfide minerals from non-value sulfide minerals in a froth flotation process for the recovery of such value minerals.

Abstract: An apparatus for mass transfer between a liquid and a gas inside a rotor having a packing. The liquid is introduced at a center of the rotor and driven outward through the packing by centrifugal force generated by rotation of the rotor, and the gas surrounding the rotor is forced inward through the rotor by a pressure of the gas, counter to the liquid flow in the rotor. The packing inside the rotor is divided into individual packing segments that together form a circular disk. Each circular ring segment is formed by at least one structured packing formed of a plurality of superimposed woven, knitted, mesh or lattice structured surfaces composed of metal, in particular sheet-metal strips, or plastic or glass fibers, to which the axis of rotation of the rotor runs perpendicular.

Abstract: A centrifugal separator and a method for separation of particles from a gas stream is disclosed. The separator includes a frame, a gas inlet and a gas outlet. A centrifugal rotor is arranged to be rotatable in the frame around a rotational axis and includes a plurality of separation plates defining separation passages between the plates. A central gas chamber in the rotor communicates with a radially inner portion of the separation passages and the gas outlet. A space surrounding the rotor communicates with a radially outer portion of the separation passages and the gas inlet. A device is configured to bring the gas stream in rotation upstream of the rotor. The centrifugal rotor is configured such that the rotational flow of the gas mixture drives the rotation of the centrifugal rotor for separating particles from the same gas stream being conducted from the space surrounding the rotor, through the separation passages between the plates and towards the central gas chamber.

Abstract: A fluid permeable member includes a support body provided in a lower portion thereof with a support plate having a fluid permeable through-hole, and a fluid permeable anodic oxide film disposed on the support plate.

Abstract: A sprinkler assembly can include a water inlet and a nozzle assembly. The nozzle assembly can include a nozzle tube having a nozzle positioned at the downstream end of the nozzle tube. The sprinkler assembly can include a user replaceable wear disc at least partially surrounding the nozzle tube. A deflector assembly can be connected to the nozzle assembly and can include a distribution plate positioned downstream of the nozzle and configured to deflect water from the nozzle. The deflector assembly can include a cage having one or more arms connected to the distribution plate and extending from the distribution plate toward upstream end of the nozzle tube. The deflector assembly can include an upstream collar portion connected to the at least one arm and having one or more load surfaces configured to contact the wear disc, wherein the wear disc is configured to bear at least a majority of a weight of the deflector assembly.

Abstract: A liquid flow device to receive fluid and laminarize the fluid flow. The liquid flow device includes a jet nozzle assembly to receive the fluid and direct the fluid through a plurality of jet channels and a flow disruptor assembly to receive the fluid from the jet nozzle assembly to generate a flow path of the fluid. The liquid flow device also includes a chamber assembly connected to the flow disruptor to receive the fluid from the flow disruptor assembly and an outlet assembly, open to an external environment to receive the fluid from the chamber assembly and output the fluid with a laminar flow pattern.

Abstract: A disposable cleaning-free paint pot comprise a pot body and a pot lid covering an opening of the pot body, the pot lid including a pot lid connector and a feed hole disposed in the pot lid connector, the adapter including an external thread disposed at an outer wall, positioning blocks disposed at an inner wall thereof, a press plate and a clamping cam; the pot lid joint is including positioning slots engaging with the positioning blocks and an annular groove for the clamping cam. The paint pot from cleaning after spray coating, the cleanliness of paint pot is guaranteed, so that the paint pot is fitted on spray gun rapidly, and the paint can be mixed in the pot body.

Abstract: A replacement nozzle for an aerosol canister including a body section including a body channel and an exit aperture in fluidic communication with the body channel, a flange section including a flange channel positioned in fluidic communication with the body channel, and an attachment section including an attachment channel positioned in fluidic communication with the flange channel, an entry aperture positioned in fluidic communication with the attachment channel, and a thread positioned on an outer surface of the attachment section operable to removably attach the replacement nozzle to a stem of an aerosol canister. The attachment of the replacement nozzle enables depression of the stem of the aerosol canister resulting in expulsion of an aerosol comprised by the aerosol canister into the replacement nozzle through the entry aperture, through the attachment channel, through the flange channel, through the body channel, and exit from the replacement nozzle through the exit aperture.

Abstract: A filling apparatus (110, 210) for a hermetically sealed bottle (200) is created by means of a dual bottle adapter (210), at least indirectly connected to the bottle (200), for an input of liquid from a storage container (100) provided with a dual container adapter (110) and at least partially filled with liquid, wherein between a liquid exit port (111) of the dual container adapter (110) and a liquid entry port (211) of the dual bottle adapter (210) a sealed-off liquid communication connection is present, and between a gas entry port (112) of the dual container adapter (110) and a gas exit port (212) of the dual bottle adapter (210) a sealed-off gas communication connection is present.

Abstract: A coating system for coating objects with a coating material includes at least one material source for a coating material, which can be fluidically connected to an application device. A feed system can be used for feeding coating material back to its material source in a feeding-back direction over a feed path. It can be determined by means of a detection device whether coating material or some other material is present in a control portion of the feed path, the detection device generating a corresponding output signal. Also specified is a method for coating objects in which it is determined during the feeding back of coating material to its material source whether regions made up of material other than the coating material are being carried along by the coating material to be fed back.

Abstract: An atomizing spray nozzle device includes plural inlets that receive different phases of materials of a coating. The device also includes an atomizing zone housing portion fluidly coupled with the inlets and shaped to mix the different phases of the materials into a mixed phase slurry. The device also includes a plenum housing portion fluidly coupled with the atomizing housing portion along the center axis of the device. The plenum housing portion includes an interior plenum that is elongated along the center axis of the device. The plenum is configured to receive the mixed phase slurry from the atomizing zone. The device also includes one or more delivery nozzles fluidly coupled with the plenum. The one or more delivery nozzles provide one or more outlets from which the mixed phase slurry is delivered onto one or more surfaces of a target object as a coating on the target object.

Abstract: An outlet fitting broadly comprises a coupler, a plug, and a gasket. The coupler engages a conduit opening of a conduit and includes an aft section, a forward section, and a radially extending flange bisecting the aft and forward sections. The aft section includes a narrowing inner surface forming a fluid passageway. The flange includes an upper surface for abutting the conduit near the conduit opening. The plug has a laterally elongated longitudinally extending central aperture. The aft section is inserted into the conduit opening and a tool inserted into the central aperture draws the plug towards the forward section and expands the aft section into secure engagement with the conduit. The gasket is also urged against the periphery of the conduit opening and forms a seal between the coupler and the conduit.

Abstract: A reactor for continuously coating tow fibers has an outer tubular member, an inner support member spaced from the outer tubular member, a reactant flowing through a space defined by the outer tubular member and the inner support member, and at least one flow promotor located on an outer surface of the inner support member for directing the reactant towards an inner surface of the outer tubular member. A system and a method for coating tow fibers are also described.

Abstract: A caulking finger includes a handle and a finger portion. The handle has a finger engagement tab at one end, while the finger portion has a tab engagement recess configured to receive the finger engagement tab of the handle. The finger portion is elastic and curved to provide a curved and pliable surface for pressing caulk into a seam or joint to a desired finish.

Abstract: A coating process is described that coats a coil-to-coil continuous substrate with a graphene-like coating. The coating process includes cleaning and activating a substrate, applying a graphene oxide dispersion to the substrate, drying the coated substrate, and exposing the dried coating to VUV radiation under a dry atmosphere. The atmosphere for the last step includes one or more inert gases and optionally one or more reactive gases to repair defects in the coating and/or to functionalize the coating. This coating process allows for the formation of a polygranular graphene-like coating intimately in contact with the substrate. The graphene-like coating coats the substrate with multiple monolayers of graphene in a continuous manner.

Abstract: Disclosed is a method for treating a grained material. A nonlimiting example of the method includes the operations of providing a workpiece having grains, exasperating a surface of the workpiece to open the grains, applying at least one coat of a base paint to the exasperated surface, applying at least one layer of clear coat on the base paint, applying at least one of a glaze and a paint on the clear coat, and surface treating to reveal grains of the workpiece. Disclosed also are items of furniture and sheet materials treated by the aforementioned process.

Abstract: A linear vibration motor includes a base including an accommodation space; a vibration unit; and a first elastic unit suspending the vibration unit in the accommodation space. The first elastic unit includes two elastic pieces located on two opposite sides of the vibration unit, each the elastic piece having a main elastic arm, a first auxiliary elastic arm and a second auxiliary elastic arm extending reversely in a bending way respectively from an end of the first auxiliary elastic arm and an end of the second auxiliary elastic arm. The main elastic arm is perpendicular to the vibration direction, the first auxiliary elastic arm and the second auxiliary elastic arm are respectively located on the two opposite sides of the main elastic arm, the first fixed arm is fixed to the vibration unit, and the second fixed arm is fixed to the base.

Abstract: Systems and methods described herein generally relate to forming a conductive layer of an ultrasound probe. The systems and methods form an ultrasound probe that includes a piezoelectric layer, and first and second matching layers. The first matching layer is interposed between the second matching layer and the piezoelectric layer. The second matching layer formed from a material having a select acoustic impedance from a laser activated molded interconnect device (MID) or a three-dimensional printer. The second matching layer being electrically coupled to the piezoelectric layer.

Abstract: A haptic actuator includes mechanical links defining a first J-trajectory and mechanical links defining a second J-trajectory as well as a motor coupled to the mechanical links so as to synchronously accelerate a first mass over the first J-trajectory and a second mass over the second J-trajectory. During a first time interval, reactive forces of the first mass accelerating substantially balance reactive forces of the second mass accelerating and during a second time interval reactive forces of the first mass accelerating do not substantially balance reactive forces of the second mass accelerating. This un-balanced condition results in a tap signal being produced.