Abstract: A device for surface peening, in particular for ultrasonic shot peening, of a component of a gas turbine, having at least one vibration device that includes a surface that impinges the blasting material, and having a holding device by which a surface area of the component can be positioned relative to the surface of the vibration device, the surface of the vibration device being subdivided into at least two adjacent partial surfaces, each including an overlapping part by which a part of the surface area of the component can be treated by blasting material impinged both by the one and by the other partial surface.

Abstract: A method, which allows high-tensile flat steel products to be manufactured with less effort includes a steel that forms a multi-phase microstructure and contains (in wt. %) 0.08-0.12% C, 1.70-2.00% Mn, up to 0.030% P, up to 0.004% S, up to 0.20% Si, 0.01-0.06% Al, up to 0.0060% N, 0.20-0.50% Cr, 0.010-0.050% Ti, 0.0010-0.0045% B, remainder iron and unavoidable impurities, being cast into a cast strip having a thickness of 1-4 mm. The cast strip is hot-rolled in-line into a hot-rolled strip having a thickness of 0.5-3.2 mm in a continuous process at a final hot-rolling temperature ranging from 800 to 1100° .C, the deformation degree being greater than 20%. The hot-rolled strip is coiled at a coiling temperature ranging from 250 to 570° C., so as to obtain a hot-rolled strip, which has a minimum tensile strength Rm of 800 MPa at a minimum breaking elongation A80 of 5%.

Abstract: A material handling system for feeding sheet material to a laser cutting system. The material handling system including a shuttle having a number of roller pairs corresponding to a number of material coils. Each roller pair holding a leading end of one of the material coils. The shuttle translating the leading end of a selected material coil to a location at which sheet material from the selected material is fed to the laser cutting system.

Abstract: An apparatus and corresponding manufacturing method for configuring a surgical needle such that the surgical needle has a barrel having a substantially elongate configuration and a point having a substantially curvilinear configuration are disclosed. First and second curving members having an axis of rotation are disposed adjacent and separated by a gap. Third and fourth curving members are slidably disposed in a path traversing the first and second curving members. When a surgical needle is inserted into the gap, the third and fourth curving members can be slid in the path to impose a holding force on the barrel of the needle and can be further slid in the path to cause curvature of the point of the needle by one of the first and second curving members. A corresponding method of manufacturing the needle having a curved point substantially without causing curvature of the barrel is also disclosed.

Abstract: A process for producing a structure in a smooth sheet-metal strip includes multiple process steps. In a first step, a first section of a smooth sheet-metal strip is fed to a first tool and a second section of the sheet-metal strip is fed to a second tool in a direction of advance. Then the sheet-metal strip is stopped. A sheet-metal machining of the first section of the sheet-metal strip is carried out using the first tool. A sheet-metal machining of the second section of the sheet-metal strip is carried out using the second tool, with the first feeding step being carried out simultaneously. An apparatus is provided for producing a sheet-metal strip of such a complex structure, which produces the structure with a very high degree of accuracy even when the materials properties differ.

Abstract: A method for making a test specimen includes machining out a chordal core from an annular forging and machining the specimen symmetrical about a chordal axis of the core. A linear cutting tool such as a wire EDM machine is used for the machining which includes at least a partially cylindrical cutting about the chordal axis with the linear cutting tool. A copper or brass tubular EDM electrode may be used. The chordal core may be machined from fat of the forging. The test specimen may have with a gauge section diameter in a range of 0.1-0.5 inches. The EDM process may include directing jets of machining fluid or dielectric in up and down along a cutting portion of an EDM wire of the EDM machine or performing the EDM process in a tank of machining fluid or dielectric with the annular forging submerged in the fluid or dielectric.

Abstract: A method for manufacturing a combination wrench includes pressing a wrench material piece in a sealed mold at a temperature without generating carbon scale to form a semifinished product including first and second driving ends and a handle interconnected between the first and second driving ends. The first and second driving ends of the wrench semifinished product are processed to form a combination wrench having a box end and an open end. The wrench material piece can be obtained by shearing a material plate.

Abstract: The cylinder/piston unit for a counterforce ram or vee ring of a fineblanking or stamping press equipped with at least one tool is continuously maintained at a preadjustable cushion pressure (P1) and is then subjected to a preadjustable displacement pressure (P2) from a connectable high-pressure source, with said pressure being set to a pressure (PU) varying between the cushion pressure (P1) and the pressure for forming or blanking by supplying a separate control oil quantity to a second accumulator via a central control unit, whereby a rise in pressure caused by the impact between the tool and the workpiece is regulated, independently of quantity of the control oil, from the pressure (P3) in the second accumulator to a permissible set pressure by discharging a significant part of the pressure pulse into a separate tank and the available cushion pressure allows ejection of the workpiece to be synchronized with retraction of the press ram.

Abstract: One object of the present invention is to provide a wire drawing die excellent in strength and wear resistance. The wire drawing die has a core formed using highly hard diamond polycrystalline body made substantially only of diamond and produced by directly converting a raw material composition including a non-diamond type carbon material into diamond and sintering the diamond at an ultra high pressure and an ultra high temperature without adding a sintering aid or a catalyst, the polycrystalline body having a mixed construction including fine-grained diamond crystals with a maximum grain size of less than or equal to 100 nm and an average grain size of less than or equal to 50 nm and plate-like or particulate coarse-grained diamond crystals with a minimum grain size of greater than or equal to 50 nm and a maximum grain size of less than or equal to 10000 nm.

Abstract: A meter proving method and system. At lease some of the illustrative embodiments are methods comprising establishing a prover time by a prover device, measuring a flow rate of a fluid with a flow meter that uses multiple measurements taken over a period of time to produce each individual flow rate value (the flow meter electrically coupled to the prover device), and generating a meter volume over the prover time based on the flow rate. The generating the meter volume based on the flow rate does not involve: generating a pulse train output signal by the flow meter; and generating the meter volume based on an attribute of the pulse train.

Abstract: A method is provided for evaluating relative wear life polymeric specimens intended for use at high temperature under high wear conditions.

Abstract: A method for testing the measuring accuracy of a measuring device (7) for gas measurements, comprising a gas inlet opening (70), comprising the steps; connecting a special reference gas, having a known concentration and having a controlled flow rate and pressure, where the flow rate and the pressure are controlled to be within certain limits, to the gas inlet opening (70); and evaluating the reading in relation to the known concentration of the special reference gas. A control device (1), for use in the method, for controlling the pressure and flow rate of a gas source connected the control device (1) so as to assure a controlled pressure and flow rate at a gas output (17) of the control device (1), which comprises a flow rate controlling element (11) and a pressure controlling element (13) connected between the gas input (10) and the gas output (17).

Abstract: An alcohol detection system for a vehicle has an alcohol sensor, for which alcohol measurement preparation processing such as heating the alcohol sensor to a predetermined temperature is performed, so that the alcohol sensor operates under the stable operation state. The alcohol measurement preparation processing is started, before a driver actually gets in the vehicle. For example, the preparation processing is started, when a predetermined manipulation of a driver on the vehicle before entering the vehicle is detected. The manipulation may be unlocking or opening of a vehicle door.

Abstract: A method for estimating the temperature of exhaust gases of a combustion engine at an output of an EGR circuit fitted on the engine, based on a model that takes into account thermal energy losses of the exhaust gases at an EGR cooler or EGR circuit, the model also taking into account thermal exchange between the exhaust gases and the walls of a duct conveying the exhaust gases to the EGR cooler. A vehicle can implement such an estimation.

Abstract: A photo, acoustic detector (200) for detecting a concentration of a sample in a sample mixture. The photo acoustic detector (200) comprises a light source (101 ) for producing a light beam for exciting molecules of the sample and a light modulator (102) for modulating the light beam for generating pressure variations in the sample mixture, an amplitude of the pressure variations being a measure of the concentration. The photo acoustic detector (200) further comprises a detector element (103) for converting the pressure variations into a detector current and a processing section (106) for processing the detector current to generate an output signal representing the concentration.

Abstract: The invention relates to an ultra fine particle sensor (1) for sensing airborne particles with a diameter in a range of approximately 1-500 nm. The sensor comprises an air inlet (2) for entry of a flow of ultra fine particles and a concentration variation section (4) capable of causing a variation of the concentration of ultra fine particles between at least a first concentration level and a second concentration level during at least one time interval. A particle sensing section (5) is provided capable of producing a measurement signal (I) varying in dependence of said variation between said first concentration level and said second concentration level. An evaluation unit (6) is provided capable of deriving data relating to said ultra fine particles form said varying measurement signal.

Abstract: The measurement is conducted by means of thermogravimetric scales (10) bearing at one end of the beam (20) a catalyst body (30) for catalysing a coking reaction of the tars present in the gas state. Precautions are taken in order to ensure homogeneity and regularity of the sampled gas flow and to guarantee predominant catalysis on the catalytic body (30), the weight increase of which gives the weight of the deposited coke and indirectly the content of tars present in the gas state in the gas to be measured. A calorimetric device (34) for analyzing gases from the coking of the tars provides a complementary and/or additional measurement. The solid tars are filtered beforehand, but their content may be measured by an auxiliary device. Possible application to analyzing gases from biomass.

Abstract: A new type of highly efficient and self-cleaning humidity sensor based on Mg2+/Na+-doped TiO2 nanofiber mats is provided. Examples show the response and recovery characteristic curves for ten circles with the RH changing from 11% to 95%. The nanofibers are manufactured by mixing together a metal salt comprising titanium, a magnesium compound, a sodium compound, and a high molecular weight material to form a mixture, electrospinning the mixture to form composite nanofibers, and calcining the composite nanofibers to yield a TiO2 nanofiber material doped with magnesium and sodium.

Abstract: A sensor device. One embodiment provides a first sensor having a first sensor surface. The first sensor surface is exposed to allow sensing of a first variable. A second sensor has a second sensor surface. The second sensor surface is sealed to inhibit sensing of the first variable, and a mold material is embedded the first and second sensors.

Abstract: A detector circuit for detecting the presence of a remote capacitive sensor having at least two terminals connected via a protection circuit that includes one or more capacitors, the detector circuit comprising: a current supply for changing the charge on the sensor and the protection circuit, a detector for measuring the voltage on one or more of the terminals; wherein the presence of the sensor is determined by changing the charge on the capacitive sensor and the one or more capacitors of the protection circuit in a predetermined manner such that the voltage measurement on the one or more terminals when the sensor is present is significantly different than when the sensor is absent.

Abstract: Determination of hydraulic properties such as porosity and permeability of soil is of paramount importance in hydrology and civil engineering. In order to achieve greater accuracy in determination of permeability of soil using falling head permeameter, the two important known constraints of human monitoring error in noting the falling water level between two selected levels and elapse time between these two levels had overcome through electronically sensing the levels between two selected points and activating the timer clock automatically by the pulses coming from senor. The precision in measurement of time lapse in 1/100th a second enables greater accuracy in estimation of permeability. Provision of perforated Teflon disc above and below the soil core facilitates in application of water uniformly over the entire surface area of soil core at top and similar way permeated water leaving the soil core uniformly without any obstruction.

Abstract: A pneumatic assembly for a pressure decay tester of printhead integrated circuits includes a pressurized air supply. A pneumatic clamping arrangement is in fluid communication with the pressurized air supply for clamping a carrier for the printhead integrated circuits such that the carrier is in fluid communication with the printhead integrated circuits. A valve arrangement applies a predetermined pressure to the carrier. A sensing arrangement senses a static pressure in the carrier. A control system is in communication with the clamping, valve and sensing arrangements to control operation thereof and to generate a discernible signal representing said static pressure such that a decay in said static pressure can be determined.

Abstract: The invention provides for a pressure-based tester for testing integrity of a platform assembly. The platform assembly includes a pair of assembled platform components fastened together and a fluid path extending into both components, the platform assembly suitable for supporting printhead integrated circuits to be tested. The tester includes a housing assembly, a regulated gas supply arranged in the housing assembly, and a retaining mechanism in fluid communication with the gas supply and configured to retain the platform assembly in fluid communication with the gas supply during testing of the platform assembly.

Abstract: Provided is a leak tester for a carrier for printhead integrated circuits. The carrier has at least one fluid inlet in fluid communication with a plurality of fluid outlets via discrete fluid paths. The tester includes a support assembly that includes at least one receptacle shaped and configured to receive at least one respective carrier, and a pressurized fluid supply arranged on the support assembly and configured to supply pressurized fluid to the fluid inlets, the pressurized fluid supply incorporating a sealing mechanism configured to engage the fluid inlets in a sealing manner.

Abstract: A cradle assembly for a pressure decay leak tester is provided. The assembly operatively receives a printhead integrated circuit carrier having a plurality of printing fluid paths defined therein, respective fluid inlets in fluid communication with respective fluid paths and a locating formation to facilitate correct location of the carrier on the tester. The assembly includes at least one complementary locating formation for engaging the locating formation of the carrier, and at least one fluid outlet for charging the carrier with fluid via a respective fluid inlet of the carrier. Also included is a clamping device for clamping the carrier to the fluid outlet, so that the integrity of the fluid paths is observable via pressure decay testing, and a control system operatively connected to the clamping device for controlling operation of the clamping device.

Abstract: There is described a novel tool and method for the isolation and pressure-testing of connections, such as welds, between a vessel and a nozzle or branch pipe. The nozzle testing tool comprises an improved seal that expands into sealing contact as testing pressure is increased. The tool can also be easily adjusted in order to accommodate variations in nozzle configuration.

Abstract: The viscosity of a heavy oil is estimated according to a power law equation which relates the heavy oil viscosity to a function of the assumed, measured, or estimated glass transition temperature of the heavy oil and the measured temperature of the heavy oil.

Abstract: Embodiments of the present invention are directed to methods and apparatus for placing a sample in a chromatographic system. The device and method feature placing samples held in a sample loop to pressurization prior to placing such sample loop in communication with high pressure conduits.

Abstract: A method for detecting overpressure inside a compartment associated with a gas turbine nacelle, the method comprising: a) measuring one or more predetermined operating conditions nominally affecting the temperature inside the compartment; b) determining a reference temperature for the compartment, corresponding to a nominal reference zone pressure, on the basis of the measured operating condition or conditions; c) measuring the actual temperature inside the compartment, corresponding to the actual compartment pressure; and d) using the measured actual temperature in the compartment and the determined reference temperature for the compartment to assess the gas pressure inside the compartment. In one embodiment, there is disclosed a system for assessing the gas pressure inside the compartment caused by an associated pressure system failure, comprising using a quantified mass leakage flow to assess gas pressure inside the compartment.

Abstract: This invention provides a tire (10) equipped with a sensor (14), attached to a rubber member (15) in the surface of the tire (10), for detecting deformation of the tire (10). The sensor (14) is adhered to the rubber member (15) with the aid of an elastic adhesive formed of a room-temperature moisture cure adhesive agent composed mainly of an acryl modified silicone resin or the like. The adhesive between the sensor (14) and the rubber member (15) is cured to form an elastic adhesive layer (16). According to the above constitution, the deformation of the rubber member (15) in the tire surface can be transmitted to the sensor (14) with high accuracy, and, at the same time, the durability of the sensor (14) can be improved.

Abstract: Provided is a tire pressure monitoring system including: a tire pressure measurement sensor including a pressure detection means for detecting an air pressure in a tire, a connection pipe for connecting an air injection valve of the tire to the pressure detection means, a fixing means for fixing the connection pipe to the air injection valve of the tire, and an air injection means connected to the pressure detection means to inject air into the tire through the pressure detection means; and a display for showing the air pressure of each tire of a vehicle to a driver, wherein the tire pressure measurement sensor is mounted in the air injection valve of the tire and transmits a pressure value of the tire to the display through wireless communication.

Abstract: The present invention relates to a fuel sensor adapted for sensing the level of fuel in a vehicle fuel tank and in particular to a fuel sensor adapted to sensing the level of fuel which would be accurate, compact and dragged. The fuel sensor of the invention is further adapted to be readily fitted in the vehicle fuel tank for measuring the fuel level efficiently and reliably. Importantly the fuel sensor is further adapted for operative connection to indicative instrument to facilitate ready and accurate reading of the fuel level in the tank.

Abstract: A device for monitoring a gas volume in a unit filled with a liquid, where the unit has an inlet line with at least one expansion chamber, and the device includes one or more buoyant bodies floating in the liquid. The floating buoyant body is connected to a shaft, fixed in the expansion chamber and mounted pivotally relative to the shaft. The gas volume above the liquid may be recorded rapidly and with high accuracy, by measuring the torque generated by the buoyant body, or an angle to the horizontal. There is also disclosed a method for monitoring a gas volume in a unit filled with liquid, by way of a floating buoyant body.

Abstract: A balancing machine for rotating bodies, particularly for wheels of motor vehicles and the like, comprising a rotating shaft supported by a supporting element which is connected rigidly to the frame of the balancing machine, at least one first measurement transducer and one second measurement transducer being coupled elastically, along perpendicular planes, to an extension of the supporting element, an actuation motor being connected to the rotating shaft by means of a belt, said actuation motor being connected on an extension of the supporting element, said extension connecting the rotating shaft to the measurement transducers.

Abstract: Provided is a sensor including a movably supported movable element and an opposing member. The sensor detects a relative positional relationship between the movable element and the opposing member which are provided with a spacing therebetween The opposing member has an impurity-doped portion which is provided to one of an opposing portion which is opposed to the movable element and an adjoining portion which adjoins the opposing portion. At least a part of the impurity-doped portion is formed on an opposite surface opposite to a surface which is opposed to the movable element, from which opposite surface an electrical wiring is led out.

Abstract: An electronic component is disclosed, and this component includes an element with an electrode section which is formed of upper electrode (74), lower electrode (72), piezoelectric unit (70) placed between upper electrode (74) and lower electrode (72), and adhesive layer (76) layered between upper electrode (74) and piezoelectric unit (70). Piezoelectric unit (70) includes piezoelectric layer (80) made of piezoelectric material containing lead, and adhesive layer (76) includes a tungsten layer made of tungsten-based material. Piezoelectric layer (80) and the tungsten layer are layered together. The structure discussed above allows preventing a piezoelectric constant from lowering and a base-point voltage from varying. The lowering and the varying have been caused by a temperature-rise.

Abstract: An angular velocity sensor includes a drive electrode section (26) for inputting a drive signal for driving a detecting element (21), a monitor electrode section (28) detecting the drive status of the detecting element (21) and outputting a monitor signal, and a sensing electrode section (27) outputting a sensing signal, which is generated due to an angular velocity given to the detecting element (21). The drive electrode section (26), the monitor electrode section (28), and the sensing electrode section (27) each have a lower electrode formed on a substrate, a piezoelectric film formed of a piezoelectric material on the lower electrode, and an upper electrode formed on the piezoelectric film.

Abstract: An acceleration sensor includes a substrate, a rocker mass, a z spring connected to the rocker mass, which allows the rocker mass to rotate about an axis, and at least one additional spring system connected to the substrate and the rocker mass. The additional spring system allows the rocker mass to deflect in an x or y direction oriented parallel or perpendicular to the axis. The z spring or the additional spring system allows the rocker mass to deflect in a y or x direction oriented parallel or perpendicular to the axis.

Abstract: A circuit board is mounted on a package via an adhesive agent as an elastic member. A sensor element is stacked in fixed relation onto the circuit board. The sensor element, the circuit board, and the package are wired with bonding wires. A magnetic member made of a ferromagnetic material is disposed between the adhesive agent and the circuit board.

Abstract: In a micromachined devices having a movable shuttle driven in oscillation, measuring the electrical charge accumulated on opposing drive capacitors to determine the displacement of the movable shuttle. Alternately, in such a micromachined device, measuring the electrical charge accumulated on a drive capacitor and comparing the measured electrical charge to a nominal electrical charge to determine the displacement of the movable shuttle.

Abstract: The invention provides an accelerometer comprised entirely in a single component of a piezoelectric or piezoresistive material. The accelerometer comprises three electrode regions each being adapted to provide a specific electrical pattern for specific acceleration directions. The invention further provides a method of determining acceleration.

Abstract: An acceleration sensor chip package includes an acceleration sensor chip; a sensor control chip; a re-wiring layer; an outer terminal; a sealing portion; and a substrate. The acceleration sensor chip includes a frame portion; a movable structure; a detection element; and an electrode pad electrically. The re-wiring layer has a wiring portion connected to the electrode pad. The electrode pad is electrically connected to a conductive bump. The sensor control chip has a sensor control electrode pad electrically connected to the conductive bump. The outer terminal is connected to the wiring portion and disposed in the outer region. The sealing portion seals the sensor control chip, the electrode pad, and the re-wiring layer, so that the movable structure is movable. The substrate is attached to the acceleration sensor chip to seal an opening portion.

Abstract: An apparatus including: a mechanically oscillatable unit; an exciting/receiving unit; and an electronics unit having an input amplifier and an output amplifier. The amplification factors of the output amplifier and the input amplifier are tunable. The control unit tunes the amplification factor of the output amplifier as a function of damping of the mechanically oscillatable unit in such a manner that the amplitude of the electrical, input signal lies within an amplitude band and that the amplification factor of the output amplifier decreases in the case of lessened damping by the medium and increases in the case of greater damping by the medium, and the control unit tunes the amplification factor of the output amplifier and the amplification factor of the input amplifier in such a manner that the total amplification factor of the electronics unit equals a predeterminable value.

Abstract: Sealing strip (1) intended to be combined between a vehicle bodywork (2) and glazing (3), characterized in that it constitutes an acoustic damping means when subjected to the action of a vibrational field; it works in shear combined with local movements of the glazing in its plane, while the bodywork deforms in the direction of the local normal to the glazing.

Abstract: Systems (50) and methods for measuring and displaying a visual and/or graphical representation of the specific modulus (E/?) of a cellular ceramic body (10), such as those used to form particulate filters, are disclosed. The ultrasonic measurement system employs an ultrasonic transmitter (52T) and an ultrasonic receiver (52R) adjacent to, but spaced apart from respective ends (16, 18) of the ceramic body. Multiple ultrasonic waves (80) are sent through corresponding multiple longitudinal portions (12P) of the honeycomb structure (12), where adjacent longitudinal portions overlap. Time of flight (TOF) measurements (TOF1, TOF2), along with other parameters describing the ceramic body, allow for the measurement of the sonic speed (cmat) of the ultrasonic waves that pass through the ceramic body as well as the attenuation (IR). The specific modulus is then calculated from the square of the sonic speed (C2mat).

Abstract: The invention relates to an examination apparatus and a method for the determination of optical coefficients, particularly of the optical absorption coefficient (?a) in an object (1) like the body of a patient. The apparatus comprises an ultrasonic scanner (20) for recording first and second pulse echoes before and after the object (1) has been illuminated with a heating light beam (11) from a (e.g. laser) light source (10). An evaluation unit (30) determines a map of temperature increase (?T(r)) caused by the heating light beam (11) inside the object (1) based on apparent displacements showing up between the second and first pulse echoes. Furthermore, the evaluation of locally adjacent temperature increases inside the object (1) allows to determine a map of the effective scattering coefficient (?eff(r)), from which the distribution of light intensity (I(r)) inside the object (1) can be calculated.

Abstract: A Tuned Resonant Insert TRI (1), is disclosed for Non Destructive Testing (NDT) which eliminates the need for a couplant, either solid or liquids including demineralized water and oils. The TRI (1) applies a tip force on a uni-morph or bi-morph ceramic with a range of 0.03 lbf to 4.0 lbf. The frequency range is 1 kHz to 6 MHZ. The preferred material type for the tip is Ultem. The length and diameter of the tip is sized to achieve optimal tip acoustical resonance for use with specific material and can range from 0.620 to 1.200 inches for the length and 0.100 to 0.400 inches for the diameter. A probe housing will house at least one TRI (1) and, in different embodiments “n” TRI (1) units. Constant force tip contact minimizes acoustical impedance at the tip to material interface, allowing for increased sensitivity without the use of a couplant.

Abstract: A system and method for ultrasonic examination of a threaded test object, and more particularly, the mounting threads of a compressed gas tube while the tube is affixed to a tube trailer is provided. The disclosed ultrasonic test instrument includes a probe having one or more transducers for transmission and reception of ultrasound pulses, a contoured wear plate, and a shoe of highly attentuative material having a thread-like exterior surface adapted to mate with the threaded surface of the test object. The shoe further includes a narrow window in the thread-like exterior surface such that the shoe absorbs most of the ultrasonic pulses transmitted from the piezoelectric crystal except for the ultrasonic transmissions passing through the narrow window to the test object.

Abstract: Reflective and slanted array channelized sensor arrays having a broadband source providing acoustic energy to a reflective or slanted array that reflects a portion of the incident signal to one or more sensing films wherein the response is measured.

Abstract: An ultrasonic probe for optical detection of ultrasonic waves includes a membrane integrated into the probe for contact with a body, the membrane being excited to vibration by reflected ultrasonic waves, leading to a change in optical path length of a beam of light directed at the membrane, which change is determined interferometrically.