Abstract: A method of detecting an abnormality in polishing of a substrate is provided. The method includes: rotating the substrate; pressing a polishing tool against an edge portion of the substrate to polish the edge portion; measuring a position of the polishing tool relative to a surface of the substrate; determining an amount of polishing of the substrate from the position of the polishing tool; calculating a polishing rate from the amount of polishing of the substrate; and judging that an abnormality in polishing of the edge portion of the substrate has occurred if the polishing rate is out of a predetermined range.

Abstract: A semiconductor processing device and a method of operating the same. The method may include measuring at least one property of a semiconductor wafer and determining a recipe for processing the semiconductor wafer based on the at least one property. The semiconductor wafer may be processed with a plurality of chemical mechanical polishing (CMP) modules based on the determined recipe, wherein the recipe comprises a value of at least one parameter for use by each of the plurality of CMP modules. The measurements may be made in situ or by an inline metrology device. The recipe and various parameters associated with the recipe may be determined by a controller of the semiconductor processing device.

Abstract: A system for lot based, multi-step wafer manufacturing processes is provided and includes a transfer apparatus, disposed among tools for performing respective process steps on each wafer of each lot of wafers transferred thereto, the transfer apparatus being configured to transfer each lot from a current tool to a next tool in accordance with a process step sequence, a dispatcher operably coupled to the transfer apparatus to modify the lot order in response to a modification condition detection, a measurement unit configured to receive each wafer of each fully processed lot and to collect measurements therefrom and a processor disposed in signal communication with the dispatcher and the measurement unit to analyze the measurements relative to the lot order for evidence that a process step of a corresponding tool is responsible for performance effects.

Abstract: A workpiece processing apparatus is provided. The apparatus includes a rotary turntable having one or more spindles thereon, the turntable being configured to rotate about a turntable axis. Each of the spindles is configured to receive and secure thereon a workpiece to be processed by the apparatus. Each of the spindles can rotate about their own independent axes. The apparatus includes one or more grind spindles that overlay the turntable and are configured to communicate with the workpieces. The apparatus processes the workpieces by transitioning between first and second operational states. The first operational state centers the spindles and the workpieces thereon under the grind spindle to condition an entire top surface of the workpieces. The second operational state offsets the spindles from the center of the grind spindle to condition a perimeter edge of the workpieces. A controller can govern the transition between first and second operational states.

Abstract: An edge grinding apparatus and method for grinding a glass substrate, with which a glass substrate can be ground by a fixed amount and the occurrence of defects can be minimized. The edge grinding apparatus includes an edge grinding unit which grinds a cut edge of a glass substrate while following the cut edge; a measuring unit which obtains positional information of the cut edge; and a control unit which receives the positional information of the cut edge from the measuring unit and controls a position of the edge grinding unit based on the positional information of the cut edge.

Abstract: Closed loop control may be used to improve uniformity of within wafer uniformity using chemical mechanical planarization. For example, closed loop control may be used to determine a control profile for a chemical mechanical planarization process to more uniformly and consistently achieve the desired extent of variation of within wafer uniformity of a semiconductor wafer.

Abstract: Exemplary embodiments of the subject invention comprise methods and apparatus concerning balanced abrading of a tire surface by an abrading tool. Such an abrading tool may comprise a pair of counter-rotating, driven abrading members, each of the abrading members having a rotational axis generally extending laterally across the tool, the abrading members being spaced apart in a lateral direction of the tool by a desired distance, each of the abrading members having an abrading surface defined by at least one outer diameter, the abrading surface extending axially relative to the rotational axis of the abrading member, wherein each of the abrading has a shaft upon which each abrading member is arranged, each of the shafts being adapted to be driven by a driving source. The tool further includes a body to which each shaft and abrading member is attached.

Abstract: According to an embodiment, a method of manufacturing a semiconductor device includes forming a wiring groove on an insulating film; forming a barrier metal layer and a metal layer; polishing the metal layer by applying a first load on the metal layer; and subsequently polishing the metal layer while applying a second load larger than the first load on the metal layer and spraying a gas onto a polishing pad. The polishing pad is in contact with the metal layer. The barrier metal layer covers an upper surface of the insulating film and an inner surface of the wiring groove, and the metal layer fills an inside of the wiring groove and covers the barrier metal layer.

Abstract: In a polishing method of the present invention, the temperature of a carrier plate is measured, and the amount of polishing removal of a workpiece (workpiece) is accurately controlled based on change in the measured temperature of the carrier plate.

Abstract: The invention relates to a method of profiling a running surface of a laid rail by means of a processing vehicle, in particular in the region of a switch, comprising placing a first copying probe element displaceable transversely to the rail in contact with the running edge or the inner side edge and machining the rail.

Abstract: A polishing apparatus polishes a substrate by bringing the substrate into sliding contact with a polishing surface. The polishing apparatus includes: a substrate holder having a substrate holding surface configured to press the substrate against the polishing surface, a retaining ring coupled to the substrate holding surface and configured to surround the substrate, wherein the retaining ring is brought into contact with the polishing surface during operation of the polishing apparatus, the retaining ring being configured to be tiltable independently of the substrate holding surface; a rotating mechanism configured to rotate the substrate holder about its own axis; and at least one local load exerting mechanism configured to exert a local load on a part of the retaining ring in a direction perpendicular to the polishing surface, the at least one local load exerting mechanism being arranged so as not to move in accordance with the substrate holder.

Abstract: A polishing system configured to polish a lap includes a lap configured to contact a workpiece for polishing the workpiece; and a septum configured to contact the lap. The septum has an aperture formed therein. The radius of the aperture and radius the workpiece are substantially the same. The aperture and the workpiece have centers disposed at substantially the same radial distance from a center of the lap. The aperture is disposed along a first radial direction from the center of the lap, and the workpiece is disposed along a second radial direction from the center of the lap. The first and second radial directions may be opposite directions.

Abstract: A portable sharpening apparatus is described. The sharpening apparatus includes a body portion and a cavity formed in the body portion for receiving an object to be sharpened. A rotatable abrasive drum capable of sharpening and having an axis of rotation is provided and the abrasive drum is located in the body portion. The apparatus further comprises a motor arranged to drive the abrasive drum and a mouth communicating with the abrasive drum and arranged in the body portion so as to direct an object to be sharpened towards the abrasive drum, wherein the mouth has a supporting means for locating an object to be sharpened at the abrasive drum, the supporting means being such that, when in use, an object to be sharpened is orientated along an axis substantially perpendicular to the axis of rotation of the abrasive drum.

Abstract: A load cup apparatus for transferring a substrate in a processing system includes a pedestal assembly having a substrate support, an actuator, and a controller. The actuator is configured to move the pedestal assembly into a loading position in contact with a retaining ring of a carrier head and to generate a retaining ring thickness signal based on a distance travelled by the pedestal assembly. The controller is configured to receive the retaining ring thickness signal from the actuator.

Abstract: A particle cleaning module includes a housing, a substrate holder, a pad holder, an actuator and a pad conditioner. The substrate holder is disposed in the housing, is configured to retain a substrate in a substantially vertical orientation, and is rotatable on a first axis. The pad holder is disposed in the housing, has a pad retaining surface facing the substrate holder in a parallel and spaced apart relation, and is rotatable on a second axis parallel to the first axis. The actuator is operable to move the pad holder relative to the substrate holder to change a distance defined between the pad retaining surface and the substrate. The pad conditioner is disposed in the housing and has a conditioning surface oriented parallel to the pad retaining surface.

Abstract: An angle grinder includes a housing, a drive unit configured to drive a usage tool, a sensor device configured to provide a rotation parameter, and a control unit configured to evaluate the rotation parameter to detect a clamped state of the usage tool. The sensor device has a yaw rate sensor configured to provide the rotation parameter in accordance with a rotational movement of the housing. The control unit triggers a safety mode in accordance with the rotation parameter or throttles the rotational speed and/or torque of the drive unit.

Abstract: While data that indicate a relationship between a dressing position P defined by a distance between a rotating shaft 11 of a polishing pad 13 and a rotating shaft 31 of a dresser 30 and shape change of the polishing pad 13 based on input of a target shape of the polishing pad 13 and alternating repetition of dressing the polishing pad 13 by the dresser 30 and measurement of shape of the polishing pad 13 by a pad shape measurement instrument 20 is acquired at a stage prior to commencement of a series of polishing steps for continuously polishing a plurality of polishing target objects (semiconductor wafer W) by a polishing tool 10, the polishing pad 13 is machined to the target shape 13 while the dressing position P is controlled, whereby the dressing position P is set during the polishing steps on the basis of a processing result of this data.

Abstract: A substrate for a magnetic recording medium having a disc shape with a central hole is provided in which the surface roughness of the principal surface of the substrate is 1 angstrom or less in terms of root mean square roughness (Rq) when a space period (L) of an undulation in the circumferential direction is in the range 10 to 1,000 ?m, and in which when a component in the vertical axis direction of a line segment Z connecting a point A with the space period (L) of 10 ?m and a point B with the space period (L) of 1,000 ?m in a curve S marked on a double logarithmic graph which is obtained by analyzing the surface roughness using a spectrum and in which the horizontal axis is set to the space period (L) (?m) and the vertical axis is set to the power spectrum density (PSD) (k·angstrom2·?m) (where k is a constant) is defined as H and a displacement at which the component in the vertical axis direction of the curve S is the maximum with respect to the line segment Z is defined as ?H, a value (P) expressed by (?

Abstract: According to one embodiment, a CMP method includes starting a polishing of a silicon oxide film by using a slurry including a silicon oxide abrasive and a polishing stopper film including a silicon nitride film, and stopping the polishing when the polishing stopper is exposed. The slurry includes a first water-soluble polymer with a weight-average molecular weight of 50000 or more and 5000000 or less, and a second water-soluble polymer with a weight-average molecular weight of 1000 or more and 10000 or less.

Abstract: An electrical lap guide having a first layer, the first layer including a material having a first resistivity, the first layer having first and second contact regions for electrically connecting the electrical lap guide to electrical leads; a second layer, the second layer including a material having a second resistivity, wherein the electrical lapping guide has a lapping axis and a layered axis, the layered axis being perpendicular to the lapping axis, the electrical lapping guide has an air bearing plane, the air bearing plane being perpendicular to the lapping axis, the second layer is disposed adjacent to a portion of the first layer in the direction of the layered axis, and the first layer extends farther in the lapping axis than does the second layer.

Abstract: Disclosed is a method of producing a glass substrate for an information recording medium including a precision polishing step of using a polishing material containing colloidal silica and performing precision polishing, under acidic conditions, on a glass material in which the amount of iron adhered on the surface is 0.5 ng/cm2 or less and the surface roughness Ra is 1 nm or less. Additionally disclosed is a glass substrate for an information recording medium produced by the foregoing method of producing a glass substrate for an information recording medium.

Abstract: The present invention provides a method of detecting and preventing grind burn from developing on a gear. The method includes performing acoustic emission testing while the gear is being ground during a grinding operation. The grinding wheel is evaluated during an eddy current test to detect material buildup on the grinding wheel which could cause grind burn. In addition, the method includes collecting swarf from the gear during the grinding operation and inspecting the swarf for an indication of grind burn.

Abstract: A machine tool is provided which comprises a machine base; a first support provided on a first rotational machine axis, the first rotational axis being mounted on the base in a fixed position relative to the base; a second support provided on a second rotational machine axis, the second rotational axis being mounted on the base in a fixed position relative to the base, wherein the axis of rotation of the second rotational axis is parallel to and spaced laterally from the axis of rotation of the first rotational axis. A mount is carried by a support arm on the second support, with the support arm being moveable relative to the second support about a rotary axis.

Abstract: A distance monitoring device is provided. The device is suitable for a chemical mechanical polishing (CMP) apparatus. A polishing head of the CMP apparatus includes a frame and a membrane. The membrane is mounted on the frame, and a plurality of air bags is formed by the membrane and the frame in the polishing head. The distance monitoring device includes a plurality of distance detectors disposed on the frame corresponding to the air bags respectively to set a location of each of the distance detectors on the frame as a reference point, wherein each of the distance detectors is configured to measure a distance between each of the reference points and the membrane.

Abstract: A chemical-mechanical polishing tool and a method for preheating the same are disclosed. The chemical-mechanical polishing tool includes: a polishing pad, a deionized water supply channel, a polishing slurry supply channel and a polishing pad conditioner; and the chemical-mechanical polishing tool further includes: a heating apparatus, adapted to heat DI water fed to the DI water supply channel; a temperature sensor, arranged close to the polishing pad to measure a temperature of the polishing pad; and a preheating control system, connected to the temperature sensor, and adapted to control the DI water supply channel to spray the heated DI water to the polishing pad, and when the temperature measured by the temperature sensor is equal to or higher than a predetermined temperature, to close the DI water supply channel, control the polishing slurry supply channel to spray polishing slurry to the polishing pad, and startup the polishing pad conditioner to dress the polishing pad.

Abstract: A method for providing an edge preparation on a cutting edge of a tool by means of an edge processing operation includes clamping the tool in a processing machine for providing the edge preparation, recording as a reference value the position of the cutting edge to be processed by means of a sensor arranged on the processing machine, carrying out an edge processing operation by means of a preparation tool, recording the position of the cutting edge again by means of the sensor arranged on the processing machine and storing the position as an actual value, monitoring the edge processing operation on the basis of a comparison between the reference value and the actual value, and comparing the actual value with a desired value for material removed on the cutting edge.

Abstract: Provided is a method of phasing a threaded grinding stone, as well as a device therefor, the aforementioned method and device being such that contact or non-contact of a threaded grinding stone with a disk dresser can be detected with high accuracy, with the result that the phasing of the threaded grinding stone can be accurately performed. For the purpose of achieving the above, a threaded grinding stone (14) is phased with respect to a disk dresser (32) prior to the engagement of the threaded grinding stone (14) with the disk dresser (32) during dressing. In performing this phasing, it is determined whether or not the threaded grinding stone (14) contacted the disk dresser (32), on the basis of a voltage (V) which is commensurate with the amplitude of the elastic wave generated in the threaded grinding stone (14) at the time when the threaded grinding stone (14) contacted the disk dresser (32).

Abstract: A system for sensing and controlling concentration of magnetic particles in magnetorheological fluid comprising a wire coil and an AC voltage generator that, when energized, creates a magnetic flux field including a fringing field. When the fringing field extends through the magnetorheological fluid, the impedance in the circuit is proportional to the concentration of magnetic particles. A reference wire coil identical to the sensing wire coil is connected therewith. A demodulator is connected to each of the coils sends an impedance difference signal to a feedback controller connected to controllable dispensing apparatus for adding a calculated amount of replenishing fluid to the magnetorheological fluid. The system may be incorporated into an integrated fluid management module having apparatus for receiving and replenishing spent magnetorheological fluid and a sensor system in accordance with the present invention for use in a magnetorheological finishing system having a carrier wheel.

Abstract: A real-time monitoring of an equivalence ratio of a gas-fuel mixture of a gas turbine engine is provided. The system includes multiple optical probes arranged on a plurality of fuel nozzles for transmitting laser beams directly through a gas-fuel mixture or indirectly by reflecting the laser beams from a surface of a centerbody or burner tube of the fuel nozzle. The system also includes one or more detectors to measure the transmitted laser beams from the multiple optical probes. Further, the system includes a data acquisition subsystem for acquiring and processing signals from the one or more detectors to determine the equivalence ratio of the gas-fuel mixture of the nozzle.

Abstract: An abrasive article for polishing a substrate surface. The abrasive article includes a holder pad assembly and an abrasive member held in place with respect to a holder pad. The abrasive member further includes a first surface engaged with the holder pad assembly, and a second surface including an abrasive. A preload mechanism is positioned to bias the second surfaces of the abrasive member toward the substrate surface. One or more fluid bearing features on the second surface of the abrasive member is configured to generate lift forces during relative motion between the abrasive article and the substrate surface.

Abstract: A grinding device for the surface treatment of rolls, for example of rolls for machines producing, finishing and/or processing webs, such as paper, cardboard or tissue machines, includes stationary components and mobile components which can be separated from each other. The stationary components include guide rails, which extend substantially in parallel to a roll axis of the roll to be treated and which are connected to a substructure. Thus, the stationary components, such as the guide rails, can remain at the place of use of the rolls, while the components that are mobile or can be transported can be easily separated from the stationary components and can be transported to other locations.

Abstract: The present invention is to provide a processing method for manufacturing a highly flat and highly smooth glass substrate with good productivity. A highly flat and highly smooth glass substrate is obtained with good productivity by processing of a glass substrate, which comprises a step of measuring the surface shape of the glass substrate prior to processing, a step of processing the surface of the substrate by changing a processing condition for each site (first processing step), and a step of finish-polishing the surface of the glass substrate that has been subjected to the first processing step (second processing step).

Abstract: The invention relates to a method for machining by grinding or polishing of very thin work pieces which are releasably fastened each to thin carriers. The work pieces are arranged together with the carriers in the recesses of at least on rotor disc of a double sided processing machine and are moved along cycloid paths between the working surfaces of the double sided processing machine. Thereby, the removal rate on the working surfaces of the double sided processing machine is either the same or the removal rate on a working surface is substantially less than the one on the opposing working surface, or on one of the working surfaces no material removal takes place. In one embodiment two work pieces are on carrier, that is, releasably fastened on upper and lower side.

Abstract: Measuring construction for measuring use conditions of a tire, configured to be mounted to a support arrangement and provided with a tilting arrangement for tilting and/or adjusting a force on a tire, wherein the tilting arrangement is provided with a measuring instrument that is connected to the tilting arrangement, at least configured and measure forces and/or moments on a tire, a wheel axle supported by the measuring instrument, and at least one actuator for driving the tilting arrangement, wherein the tilting arrangement comprises a foldable construction connected to the at least one actuator.

Abstract: A system and method for processing a wafer includes a charge neutralization system. The wafer processing system includes a wafer measuring device that can measure characteristics of a surface of the semiconductor wafer. One or more wafer processing stations perform a chemical mechanical polish (CMP) process on the wafer surface. A desica cleaning station can clean and dry the semiconductor wafer. The wafer processing system further includes a charge neutralizing device that can alter a surface charge of the wafer surface.

Abstract: A vane for a turbine assembly of a turbocharger includes a first airfoil that includes a length between a leading edge and a trailing edge, a second airfoil that includes a length between a leading edge and a trailing edge where the length of the first airfoil optionally differs from the length of the second airfoil, and one or more intra-vane throats defined at least in part by the first airfoil and the second airfoil. Various other examples of devices, assemblies, systems, methods, etc., are also disclosed.

Abstract: A method of determining parameters for a burnishing operation includes: using a rolling burnishing element to burnish at least two segments on a selected surface of a material sample, the segments having a common width and overlapping each other by a preselected overlap value; measuring the resulting hardness of the surface; and selecting a working overlap value for a subsequent burnishing operation on a workpiece, based on the measured hardness.

Abstract: A lapping row tool comprising a plurality of bending nodes having a space between adjacent ones of said nodes and each of which has an end surface to manipulate a row of magnetic heads during lapping. A bridge extends along the end surfaces of the bending nodes and across the space between the adjacent bending nodes. The bridge provides a surface for holding the row of magnetic heads that prevents the flexing of the row into the space between the bending nodes during lapping while allowing the bending nodes to manipulate the row during lapping.

Abstract: A post-process sizing control device is provided with origin compensation means for controlling a size measuring device to measure an actual size of a workpiece portion and for compensating the origin of a wheel head by a position compensation amount which corresponds to a difference between the actual size and a theoretical size derived from calculation and size measuring interval setting means for setting the number of workpieces which should be ground during the next size measuring interval which begins after the preceding origin compensation operation and ends with the next origin compensation operation. The size measuring interval setting means sets the number of workpieces which should be ground during the next size measuring interval, based on an average position compensation amount derived by dividing a position compensation amount for the last workpiece ground during the present size measuring interval by the number of workpieces ground during the present size measuring interval.

Abstract: In the case of a method for the material-removing fine machining of a workpiece surface of a workpiece, in particular for the honing or finishing of workpiece portions having substantially rotationally symmetrically curved workpiece surfaces, at least one fine machining tool machines the workpiece surface and, by means of a measuring system, a measurement of the workpiece surface is performed. In this case, at at least one measuring position, radar radiation is directed onto the workpiece surface, and the radar radiation reflected from the workpiece surface is acquired and evaluated for the purpose of determining at least one surface measurement value.

Abstract: Processing a wafer using a double side grinder having a pair of grinding wheels. Warp data is obtained by a warp measurement device for measuring warp of a wafer as ground by the double side grinder. The warp data is received and a nanotopography of the wafer is predicted based on the received warp data. A grinding parameter is determined based on the predicted nanotopography of the wafer. Operation of the double side grinder is adjusted based on the determined grinding parameter.

Abstract: An apparatus and method for lens surfacing. The apparatus includes a voice coil, piezo stack and cutter connected by a connection mechanism and regulated by a hierarchical sliding mode control system. The invention allows for both coarse and fine movements of the cutter during surfacing.

Abstract: When surface grinding finish for decoration or other purposes is performed by applying a film to the front surface of a metal plate that is welded linearly with penetration from the rear surface side thereof. In this manner, the metal plate can be subjected to the surface grinding finish such that an appearance similar to weld marks is not created.

Abstract: The present invention is a method for slicing a workpiece into wafers by pressing a cylindrical workpiece held with a workpiece holder against a wire row formed by a wire spirally wound between a plurality of wire guides and making the wire travel while supplying a slurry to a contact portion between the workpiece and the wire, wherein the workpiece is sliced with an axis direction of the workpiece inclined with respect to a plane formed by the wire row, after the workpiece is inclined in such a manner that a side far from the wire row plane is a side where the wire guides are to be axially expanded. As a result, there is provided a method for slicing that enable wafers having a good Warp shape to be obtained by precisely slicing a workpiece with a wire saw.

Abstract: A tangential grinding resistance measuring method includes obtaining an abrasive grain section area which is at a predetermined infeed depth from the highest top surface of abrasive grains on a grinding wheel; calculating the tangent of a half vertex angle of a conical model for cutting edges of the abrasive grains which model takes the abrasive grain section area as its bottom surface and the predetermined depth as its height; setting grinding parameters; and calculating a tangential grinding resistance from the grinding parameters and the tangent.

Abstract: A machine tool is provided which comprises a machine base (10), a first support (20,100) mounted on a first rotational machine axis on the base, and a second support (22,102) mounted on a second rotational machine axis on the base. The second rotational axis is parallel to and spaced laterally from the first rotational axis and carries a mount (38,112) moveable relative to the second support along a first linear machine axis orthogonal to the second rotational axis. A control arrangement is operable to control the orientation of the first support on the first rotational axis, and the orientation of the mount relative to the second rotational axis and its location along the linear axis, so as to govern the position and orientation of the first support and the mount relative to each other. Existing machine tools often use long linear guide rails and stacked orthogonal axes which introduce alignment and offset errors.

Abstract: The disclosure relates to abrasive articles useful in chemical-mechanical polishing (CMP), the articles including a substrate with opposite major surfaces, an abrasive material overlaying at least a portion of at least one of the major surfaces, and at least one of a radio frequency identification (RFID) tag, a RFID tag reader, or a sensor for providing CMP information to a transmitter positioned near the substrate, the transmitter positioned near the substrate and adapted to wirelessly receive CMP information and wirelessly transmit the CMP information to a remote receiver. The disclosure also relates to a CMP pad conditioner for wirelessly communicating CMP information to a remote receiver, a CMP process monitoring system for wirelessly communicating CMP information to a remote receiver, and a method for conditioning a CMP pad using a CMP process monitoring system for wireless communicating CMP information to a remote receiver.

Abstract: It is one object of the present invention to provide a program writing method of numerical controller, a numerical controller and a cutting machine controlled thereby, achieving the writing of a plurality of programs relating to one axis to perform a high efficiency in a lot of productions. A next or later user-set-program controlling a duplicated axis controlled by plural user set programs identifies a virtual axis virtually controlled by one user set program. A program is written to replace the duplicated axis with the virtual axis. A control amount calculated by the user set program identifying the virtual axis is added to a control amount inputted to a correspondent axis driving program as a control amount of the duplicated axis before replacing the virtual axis.

Abstract: The part to be machined (2) is attached so that its axis lies in a position exactly determined relative to the base of the machine (1) and to the pedestal (3) due to the flanges (8) and the rear face (9) of the V formed on the pedestal, and due to an intermediate member (11) having the shape of a crown sector in which the concave cylindrical faces (23) are adapted to the part (2). The part is pressed against the faces (23) by a lug (14) actuated by the calliper (15). The part (2) can be rotated by a floating pin actuated by a servomotor in a determined position relative to the base of the machine (1).

Abstract: A micro-abrasive blasting device and method for perturbation control using a plurality of delivery conduits of various lengths and/or apertures. The user is able to individually open and close bypass conduit pinch valve(s) external to micro-abrasive blasting device to affect the perturbation intensity internal to the mixing chamber. By selectively opening and closing flow through delivery conduits it is possible to provide a more consistent perturbation rate and select the perturbation intensity internal to mixing chamber.