Abstract: A tribometer and technique for determining torque at a physical interface of multiple rotating components. The tool and technique include aligning components about a rotational axis for independent rotation of each component. The components are in physical interface during the rotating with a resultant frictional torque. The torque may be measured by one or more torque meters during the rotating. This measured torque may be compared against an estimated torque for tool accuracy. Further, parameters such as load, temperature, component material, rotating rpm differentials and others may be varied to determine effect on measured frictional torque.

Abstract: A whole-vehicle-based method for evaluating extreme pressure and antiwear properties of grease includes injecting the grease onto a key bearing pin and causing the engineering machine to operate without load is disclosed. The method includes causing the engineering machine to operate under a load of 10% to 150% rated load at least once, viewing and analyzing a wear condition of a surface of the bearing pin, and issuing a whole-vehicle-based evaluation report of extreme pressure and antiwear properties of grease. The engineering machine is caused to operate once under a load of 10% to 150% rated load for 0.5 min to 100 h.

Abstract: The present invention is a device to provide a lab consistent accelerated wear test on an agriculture or industrial ground working tool. The circular media bin is filled to a proper level with an abrasive media. The sample tool is moved in a circular path though the abrasive media. A library of consistent accelerated wear test data is accumulated with the device. This library is correlated with industrial ground working tool usage in field conditions. This provides a math model that predicts tool wear and facilitates virtual tool design optimization.

Abstract: Methods, systems, and computer readable media for taking measurements of a material, including determining material anisotropy, are provided. According to one aspect, a method for determining tissue anisotropy comprises: applying, to a tissue sample, a first force having a direction and having a coronal plane normal to the direction of the force, the first force having an oval or other profile with long and short axes within the coronal plane, the long axis being oriented in a first direction within the coronal plane, and measuring a first displacement of the tissue; applying, to the tissue sample, a second force, and measuring a second displacement of the tissue; and calculating a tissue elasticity anisotropy based on the measured first and second displacements. Furthermore, by applying the first and second forces multiple times, tissue viscosity, elasticity, or other anisotropy may be calculated from the multiple displacement measurements.

Abstract: A system for causing wear to a material in representative downhole conditions is provided, and can include a housing with a chamber at least partially filled with a fluid, an abrasion device at least partially immersed in the fluid, a heat transfer element thermally coupled to a housing, an engagement arm coupled to the housing and a test sample attached to the engagement arm that can apply an engagement force to the test sample causing engagement of the test sample with the abrasion device. An actuation device can displace the abrasion device relative to the test sample, and cause wear of the test sample during a wear test in response to the engagement of the test sample with the abrasion device. A controller can control a thermal output of the heat transfer element to maintain the chamber within a temperature range that is representative of the downhole conditions.

Abstract: A balance for air resistance testing is provided. The air resistance testing comprises 2N dual-hole beam sensors and an upper plate; wherein, the 2N dual-hole beam sensors are arranged beneath the upper plate and fixed to the upper plate; each dual-hole beam sensor comprises a beam, an upper hole and a lower hole, the upper hole and the lower hole are arranged along the longitudinal direction of the beam, the upper hole is arranged at the upper part of the beam, and the lower hole is arranged at the lower part of the beam.

Abstract: Lubricity of a sample of lubricant may be determined by precisely measuring temperature from friction generated between two or more moving parts in contact under force. For example, to carry this out, a rotatable pin and vee block test apparatus set forth in ASTM D2760-95 (Reapproved 2010) can be provided, and modified to provide its rotating pin with a hole longitudinally along an axis of the pin about which the pin rotates during testing. The hole is configured to receive, and for the testing receives, a thermocouple to measure temperature during the testing.

Abstract: The invention relates to a test method and apparatus for measuring the frictional properties of a fluid and comprises; a first specimen holder which is adapted to hold a first specimen in the fluid being tested in contact with a second specimen surface of a second specimen in a second specimen holder, with means for applying a measurable load between the two specimens, and with oscillatory driving means for oscillating at least one of the specimen holders along a first direction, and a motion inducing means, for inducing a motion between the first and second specimen holders in a second direction to induce a compound movement between the specimens which has been found results in more accurate readings. The first specimen holder is connected to a shaft which is induced to move in the first direction being the direction of the length of the shaft and the motion inducing means for inducing a motion in a second direction may be an off-centre counter weight located on the shaft.

Abstract: A thrust bearing for a vehicle includes an upper case that abuts against a vehicle body-side attaching portion and a lower case on which the upper case is provided so that the lower case is rotatable with respect to the upper case about an axial center AX of a piston rod used in a shock absorber of a suspension of the vehicle, characterized in that the thrust bearing further includes a load sensor for measuring a load vertically acting on the suspension.

Abstract: A system for automating load conditions on a test specimen includes a test equipment assembly that includes one or more test components configured to apply load to the test specimen. The system includes a control system to actuate the load, and includes a controller that receives and transmits data to sensors and actuators operatively connected to the test equipment assembly. The system includes a data analyzer connected to the control system to transmit a loading sequence to the controller for actuating the test equipment assembly. The data analyzer receives and processes the data from the controller to determine whether the test specimen is within an acceptable stress range as the test equipment assembly performs the loading sequence, and transmits data to the controller to reduce the load on the test specimen if the acceptable stress range is exceeded.

Abstract: A bearing of a wind turbine, wherein the bearing is lubricated with a lubricant for reducing wear and fatigue of the bearing, the bearing is sealed such that the amount of lubricant which is leaking out of the bearing is minimized, is provided. The bearing includes a ventilation device with at least one pressure compensation hole for enabling a pressure compensation between the sealed bearing and the ambient. The ventilation device further includes a compressor unit, which is connected with the pressure compensation hole. Thus, a compressed medium can be selectively blown through the pressure compensation hole to ensure that the pressure compensation hole remains substantially unobstructed such that overpressure within the bearing compared to the ambient is minimized and leakage of lubricant out of the bearing is reduced. A wind turbine including such bearing and an associated method is also provided.

Abstract: A radial rolling-bearing testing device includes a housing, a lubricant reservoir provided inside the housing and configured so as to retain lubricant in which a portion of a radial rolling bearing is immersed, a rotary shaft which is supported so as to freely rotate inside the housing and which an inner ring of the radial rolling bearing is fitted outside, a rotational driving section which is configured so as to rotate the rotary shaft, a load applying section which has a pressurizing device and is configured so as to apply a load to the radial rolling bearing, and a vibration sensor configured so as to detect a vibration in the radial rolling bearing. The vibration sensor is provided on an outside of the housing, and between the pressurizing device and the radial rolling bearing in a direction in which the load applies.

Abstract: A universal tester includes modular sample stages, each dedicated to a test configuration. The modules are manually coupled to the base of the tester and automatically recognized for activation of the correct software relevant to its configuration and test scripts. As a result, no extraneous script can be activated erroneously by an operator. A single motor in the frame of the tester actuates the drive of each sample stage through a drivetrain that is automatically engaged by the manual installation of the stage. Means for controlling and/or measuring temperature, humidity, voltage, resistance, and acoustic emissions are provided through dedicated expansion slots and cards that activate respective software. An electronic identification in each card ensures that only relevant software is enabled.

Abstract: A method and a device measure tribological values of samples with a rheometer. Wherein measuring parts of the rheometer are replaced by the samples and the surfaces of the samples are moved into frictional contact relative to each other. Accordingly, it is provided that all parts of the rheometer supporting the samples in frictional connection or frictional contact and forming the rheometer power circuit, including a spring unit pressing the samples against each other, are regarded as an oscillatory circuit. Oscillation properties of the spring unit are relevant to oscillation properties of the oscillatory circuit. The oscillation properties of the spring unit are adjusted taking into consideration resonance oscillations or effects produced by changing or different measurement conditions expected with the respective measurement.

Abstract: The quality and/or aging of an oil is monitored, notably in-situ, using a resonator sensor, for example a quartz crystal microbalance sensor (QCM). Changes of the frequency response of the sensor may be used to detect or monitor the presence of one or a combination of water, fuel, metallic debris, plastic debris and reaction products from degradation of oil components and/or oil additives (including oxidation products and acids). At least one of the major surfaces of the resonator sensor may include a component capturing surface layer provided with impression sites adapted to retain components of the oil indicative of the oil's quality, aging or contamination and both major surfaces of the sensor are preferably immersed in the oil to be monitored.

Abstract: A method for detecting a preload residual rate involves: a. installing a temperature sensor on one of two preloaded elements; b. making the two preloaded elements to move with respect to each other, and recording a time-related temperature variation sensed by the temperature sensor, so as to obtain an initial temperature-rising curve; c. making the two preloaded elements to move with respect to each other, and recording a time-related temperature variation sensed by the temperature sensor, so as to obtain a detected temperature-rising curve; and d. comparing the initial and detected temperature-rising curves, so as to obtain the preload residual rate between the two preloaded elements of the step c to the step b. The method detects a preload residual rate applied to an object when the object is operating while being advantageous in terms of cost, service life, response and accuracy.

Abstract: A device for transient measurement of motion resistance between test substance and one or two test surfaces, comprising a tension/compression force transducer, a speed and/or torque controlled motor with position encoder, rails for mounting a movable sled, method for applying a normal force on the test specimen and computerized data acquisition. The tension/compression force transducer is capable of measuring the transient resistance to motion of the sample mounted to the movable sled in either horizontal direction or in reversible motion oscillatory pull/pull direction at variable frequency and amplitude. The force transducer is capable of precise measurement of the full motion record of the test material from the initiation of motion to the steady state movement.

Abstract: A lubricity testing apparatus may have a first surface configured for moving against a second surface, a second surface, a measurement device in communication with the first surface, and an actuator in communication with the first surface. A fluid may be circulated about or over at least one of the surfaces. The measurement device may measure at least one force encountered when the first surface moves against the second surface. The actuator may move the first surface against the second surface. At least one force related to the first surface may be measured as the first surface moves against the second surface to determine the lubricity of the fluid.

Abstract: A method and apparatus for monitoring lubricity consists of a cylindrical cell assembly (80) capable of withstanding high pressure and high temperature with a movable rotor (26) abrading a solid sample (28) while submerged in a liquid sample (74). A loading device (42) moves a bottom shaft (46) supporting the solid sample (28) as said solid sample (28) abrades and is moved upwards, and its movement is measured by a displacement sensor (40). Liquid sample (74) is drained through solid sample (28) into receiver (38) to measure filtration of solid sample (28). Heat is provided via a heater (64) and pressure is controlled via pressurization media (72).

Abstract: Provided herein is an apparatus, having a cylindrical structure extending from a base; a stator assembly having a stator ring and a plurality of stator teeth extending from an outer diameter of the stator ring; and a stator assembly support having a supporting means for supporting at least one of the stator ring or the plurality of stator teeth, wherein the stator assembly support is configured to dampen mechanical vibrations in the base.

Abstract: A system for simulating wet runway conditions by using a liquid container that is placed inside an aircraft. The liquid container is connected to a nozzle that sprays water in front of the wheels of the aircraft. A valve is used to control the flow of water from the nozzle. Systems, such as the braking system of the aircraft, can then be tested in wet runway conditions simulated by the system. The amount of water sprayed from the nozzle can also be electronically controlled in relation to the speed of the aircraft, such that the nozzle sprays a nearly uniform layer of liquid in front of the wheels. The system can also be modified to include two tanks to manipulate the center of gravity of the aircraft.

Abstract: Artificial or synthetic synovial fluids and methods for making such fluids are disclosed. The fluid includes selected proteins, phospholipids and hyaluronic acid and mimics the properties of human synovial fluid.

Abstract: Intrinsically calibrating friction mensuration device has a drive unit with controllable motive member, configured to receive a controllable propulsion force, and to apply tractive force to a test piece on a surface. A force engine couples to the motive member, and applies the controllable propulsion force. The device includes a controller imposing a propulsion control signal actuating the force engine to produce the propulsion force. A force sensor is between the drive unit and the test piece, producing a force signal responsive to a sensed force between the drive unit and the test piece. The drive unit can self-propelled or stationary. A method includes applying an increasing tractive force to a test piece at rest; measuring the tractive force; identifying the maximum tractive force applied at incipient motion; identifying the transition between the resting test piece and incipient motion; determining the SCOF; continue motion and determine the DCOF.

Abstract: A lubricant deterioration detecting device includes an arcuate optical fiber having one end positioned in face-to-face relation with a light emitting element and also having the opposite end positioned in face-to-face relation with a light receiving element, and a measuring gap for intervening a lubricating agent is provided in a portion of the arcuate optical fiber. In the vicinity of the measuring gap, a resistance element, the amount of deformation of which varies with change in state of lubrication performed with the lubricating agent, is provided for flowing of the lubricating agent within the measuring gap.

Abstract: A test apparatus and methods of measuring wear of a material with a laser displacement measurement apparatus based upon displacement of a test sample of the material or the wear of a testing surface and a specimen. A lubricant test method and apparatus measures the thickness of a lubricant film between two test surfaces by comparing the location of the test surfaces at rest and dynamically.

Abstract: A mounting system for samples and instruments for use with a measuring device such as a surface forces apparatus has a housing and a sample mount assembly positioned within the housing. The sample mount assembly has a pivot arm having a first edge and a flexing section. A spring has a first end coupled to the pivot arm. A first sample holder is coupled to the second end of the spring. A second sample holder is positioned in proximity to the first sample holder.

Abstract: A device for the measurement of the influence of friction force on the wear characteristics of a material surface comprises a frame with a cover. A shaft is installed in the frame. A moveable element of a friction pair is fixed on the shaft. A holder of a pressed element of the friction pair and a clamp which applies a regulated load on the holder with the pressed friction element are installed in the cover. The holder of the pressed friction element is installed in a holder frame with first membranes which allow the motion only perpendicular to the axis of holder frame. The holder-frame is installed in the cover also with second membranes that allow it to move only in its axial direction. The system of the membranes damps the impact of inertial forces on the friction pair.

Abstract: A test device for the tribological examination of materials, including at least one first test body that has a first test surface, a drive unit for this at least one first test body that can be driven in oscillating and/or rotating fashion, a measurement device for measuring forces that act on the one hand essentially parallel to the direction of an oscillating introduction of force and/or in the circumferential direction of a rotational introduction of force of the drive unit of the at least one second test body and on the other hand for acquiring the test forces that act between the at least one first test body and the at least one second test body, in addition, a load regulating device is provided that regulates the test force acting between the two test bodies, the prespecified test force being applied to the test bodies with the aid of a decoupled bearing of the drive unit.

Abstract: A method is provided for invoking condition monitoring and predicting parametric equipment and lube condition among a plurality of machines; relying on individual or multiple machine and or lube combinations; comprising establishing a based routine accepting information from multiple sources to simultaneously calculate and compare measured and projected conditions relative to parameters selected to be critical; including multiple condition monitoring techniques like: lube analysis, vibration analysis, thermography, ultrasound and equipment lube monitoring techniques whereas parameters monitored are variables and a specific parametric value represents condition or a group of variables together represents a condition; said variables are not to be confused with attribute data indicating pass/fail without identifying a specific parametric value. The process outputs the specific parameter and days to exceed specified condemning limit for each combination of equipment and lube selected.

Abstract: This invention is a method for determining the quality of lubrication oil added to a quantity of used oil in an operating engine or mechanism such as occurs during an oil change or when additional oil is added to maintain the vehicle manufacturer's specified total volume of oil. The method is based on identifying the electrical resistivity characteristics of the oil addition, representative of both the base oil formulation and its additive package, and, through comparison with previously-generated resistivity data on multiple oils identifying the oil addition. The added oil may then be compared with manufacturer specifications for the specific application to determine whether it meets recommended manufacturer requirements.

Abstract: A Lubricating grease composition comprising a base oil and a thickener system comprising (a) a lithium soap of a C12 to C24 hydroxycarboxylic acid and (b) an alkaline earth metal salt of a C2 to C12 dicarboxylic acid. The lubricating grease compositions exhibit increased water resistance and shear stability together with excellent oil bleeding properties. The lubricating grease compositions also contain lower levels of lithium than are present in a conventional lithium based grease compositions.

Abstract: A load cell for measuring extremely low level, anisotropic biaxial loads is disclosed. The system includes at least one load cell of a specific geometry and dimension which, when mounted, provides a rotationless system accurately transmitting both normal and shearing strains to strain gauges mounted thereon. More specifically, by shaping the load cell so as to concentrate the strains imposed thereon, detection of extremely minute loads, such as coefficients of friction, can be measured.

Abstract: A manufacturing method of a magnetic recording medium having a surface where a lubricating layer is provided, the manufacturing method includes the steps of: applying a lubricant so that the lubricating layer is formed; and inspecting the magnetic recording medium where the lubricating layer is formed; wherein the step of inspecting includes a first step of floating a magnetic head over the magnetic recording medium or sliding the magnetic head on a surface of the magnetic recording medium; a second step of adhering a medium facing surface of the magnetic head to a surface of a substrate for measuring, standing the medium facing surface of the magnetic head on the surface of the substrate for measuring, and transferring the lubricant from the medium facing surface of the magnetic head to the substrate for measuring; a third step of measuring an amount of the lubricant on the surface of the substrate for measuring; and a fourth step of determining whether the amount of the lubricant is proper.

Abstract: A portable apparatus and method for demonstrating different characteristics of different fluids that includes different fluid sumps or chambers for receiving samples of the different fluids. A test shaft having different portions that are immersed in the different fluid samples in the chambers is driven by an electric drive motor at a substantially constant speed while substantially the same amount of friction or force is applied to the different portions of the test shaft at different times to increase the resistance presented to the drive motor. The additional amount of current drawn or power absorbed by the motor or strain induced in the motor drive shaft during the application of such friction or force to the different portions of the test shaft is monitored and compared to provide a comparison of the friction or power loss characteristics of the different fluid samples.

Abstract: A method for diagnosing a fluid includes sensing a property of the fluid and the temperature of the fluid at the time the property is sensed, then determining the status of the fluid from the sensing. The sample volume may be small in comparison to the total fluid volume.

Abstract: A method is provided for invoking condition monitoring and predicting parametric equipment and lube condition among a plurality of machines; relying on individual or multiple machine and or lube combinations; comprising establishing a based routine accepting information from multiple sources to simultaneously calculate and compare measured and projected conditions relative to parameters selected to be critical; including multiple condition monitoring techniques like: lube analysis, vibration analysis, thermography, ultrasound and equipment lube monitoring techniques whereas parameters monitored are variables and a specific parametric value represents condition or a group of variables together represents a condition; said variables are not to be confused with attribute data indicating pass/fail without identifying a specific parametric value. The process outputs the specific parameter and days to exceed specified condemning limit for each combination of equipment and lube selected.

Abstract: There is disclosed a lubricating composition comprising an oil of lubricating viscosity formulated with an additive package comprising at least one overbased metal detergent, at least one neutral metal detergent, and at least one phosphorus-based wear preventative. Methods for improving oxidation performance in a TO-4 fluid for use in heavy vehicle machinery are also disclosed.

Abstract: A manufacturing method of a magnetic recording medium having a surface where a lubricating layer is provided, the manufacturing method includes the steps of: applying a lubricant so that the lubricating layer is formed; and inspecting the magnetic recording medium where the lubricating layer is formed; wherein the step of inspecting includes a first step of floating a magnetic head over the magnetic recording medium or sliding the magnetic head on a surface of the magnetic recording medium; a second step of adhering a medium facing surface of the magnetic head to a surface of a substrate for measuring, standing the medium facing surface of the magnetic head on the surface of the substrate for measuring, and transferring the lubricant from the medium facing surface of the magnetic head to the substrate for measuring; a third step of measuring an amount of the lubricant on the surface of the substrate for measuring; and a fourth step of determining whether the amount of the lubricant is proper.

Abstract: A method is described to determine the valve train wear performance of a lubricating oil by adding to the lubricating oil from about 2% to about 9% by weight, based on the total weight of the lubricating oil, of a mixture of at least three carbon black components of mixed particle size and measuring the wear induced in a wear test.

Abstract: The present invention provides a medical device, preferably a contact lens, which comprises an antimicrobial coating including at least one layer of polyquat of formula (I) or (II). The antimicrobial coating on the medical device of the invention has a high antimicrobial efficacy against microorganisms including Gram-positive and Gram-negative bacterial, a low toxicity, low coefficient of friction, and increased hydrophilicity while maintaining the desired bulk properties such as oxygen permeability and ion permeability of lens material. Such lenses are useful as extended-wear contact lenses. In addition, the invention provides a method for making a medical device, preferably a contact lens, having an antimicrobial coating thereon.

Abstract: A method and an apparatus for testing the adhesive strength of overlays attached to the inside of plain bearing bushings. The method is characterized in specifying clearance between the plain bearing bushing tested and a rotating or oscillating pin extending through the bushing. Next, feeding a liquid medium into the gap between the bushing and the pin and oscillating the plain bearing bushing and pin relative to one another perpendicularly to the bushing axis for a given period and examining the bushing after the load test. The corresponding apparatus comprises a pin mounted rotatably in a pin receptacle and on which there is arranged a first drive mechanism. In addition, a bushing receptacle is provided, in which the plain bearing bushing is fitted, wherein the pin is mounted with predetermined clearance in the bushing. The apparatus additionally comprises a mechanism for bringing about oscillating relative movement of bushing receptacle and pin receptacle.

Abstract: A friction test apparatus includes a base structure and a receptacle secured to the base structure. At least three lower test balls are positioned in the receptacle. The friction test apparatus includes a motor having a rotatable shaft providing powered rotation of the shaft. An upper test ball is positioned on the shaft in a chuck, and contracts the at least three test balls in the receptacle in use. The chuck may include tapered inner surfaces that frictionally engage the upper test ball along a substantially continuous ring of contact to prevent rotation of the upper test ball relative to the chuck during operation. The receptacle may include a fluid inlet and a fluid outlet to permit fluid in the receptacle to be changed.

Abstract: A test apparatus for measuring surface friction of a damping material such as brake pad insulator material includes a rotor configured to support the damping material for rotation therewith, an actuator pressurizable to apply axially-inward force to the damping material and a stator configured to support the actuator. A sensor determines the force applied to the actuator and a torque cell is axially aligned with the rotor for measuring torque of the rotor in relation to force applied to the damping material. The calculation of surface friction of the damping material is possible based on the measured load and torque. A method of measuring surface friction of a brake pad insulator material as well as a method using a brake dynamometer is also presented.

Abstract: A friction test apparatus includes a base structure and a receptacle secured to the base structure. At least three lower friction surfaces are positioned in the receptacle. The friction test apparatus includes a motor having a rotatable shaft providing powered rotation of the shaft. An upper friction surface is positioned on the shaft in contact with the at least three friction surfaces in the receptacle. The receptacle includes a fluid inlet and a fluid outlet to permit a fluid in the receptacle to be changed.

Abstract: The present invention relates to a device for measuring the static and/or dynamic friction coefficient of a surface, in particular a natural or artificial grass surface, which device comprises a housing placed on supports, which is to be positioned on the surface to be examined; a rotatable shaft, which is vertically disposed in said housing; a body connected to the end of said shaft that faces towards the surface, which body comprises a contact surface which can be brought into contact with the surface to be examined; as well as measuring means for measuring, during operation, the torque caused by the friction between the surface to be examined and the contact surface of the rotating body. The object of the present invention is to provide a device for measuring the static and/or dynamic friction coefficient of a surface which provides a more reliable and reproducible measuring result and which is furthermore user-friendly and easy to transport.

Abstract: A sensor 30 has first and second electrodes 32A, 32B spaced to define a gap 34 therebetween. The electrodes are formed on a substrate which can be covered with a film of material. The width of the gap 34 is different at different positions on the electrodes 32. This results in a sensing characteristic which can be made substantially linear, without sensitivity varying with film thickness, which arises from the use of a constant gap width. The sensor can be used to detect or measure film or liquid layer thickness, or solid material deposition.

Abstract: The present invention relates to an apparatus, a method, and a sensor for scanning engine oil of a vehicle. An apparatus for scanning engine oil according to an exemplary embodiment of the present invention includes an oil property measuring part for measuring physical and chemical properties of engine oil; a driving condition measuring part for measuring a engine driving condition; a control portion where predetermined values about conditions of engine oil according to engine driving conditions are stored as set values, for selecting a set value corresponding to a measured engine driving condition and calculating a result value about a quality of engine oil on the basis of comparison with a measured value determined according to an engine driving condition inputted from the driving condition measuring part and the set value; and an output part for outputting the result.

Abstract: The quantitative determination of two contaminants of a fluid is carried out in the following steps: detection of permittivity ? and viscosity v of the fluid; determination of the quantity of the first contaminant 11e on the basis of a difference between detected permittivity ?? and a first preset value 10e; estimation of viscosity 12n on the basis of the quantity of the first contaminant 11e; and determination of the quantity of the second contaminant on the basis of a difference between detected viscosity v and estimated viscosity 12n.

Abstract: A miniaturized sensor device comprises at least one pair of active projecting elements or cantilevers, which are set parallel to one another and at a micrometric or sub-micrometric distance apart and are designed to be submerged at least partially in a fluid. Each pair comprises a first cantilever, equipped with actuator means, and a second cantilever, equipped with sensor means. The actuator means can cause a movement of the first cantilever, whilst the sensor means can detect a movement of the second cantilever, induced by the movement of the first cantilever, for generating accordingly a measurable signal, which represents the lubricating capacity of the fluid.

Abstract: A method is provided to select appropriate material properties for turbulent friction drag reduction, given a specific body configuration and freestream velocity. The method is based on a mathematical description of the balance of energy at the interface between the viscoelastic surface and the moving fluid, and permits determination of the interaction of turbulent boundary layer fluctuations with a viscoelastic layer by solving two subtasks—i.e., a hydrodynamic problem and an elasticity problem, which are coupled by absorption and compliancy coefficients. Displacement, velocity, and energy transfer boundary conditions on a viscoelastic surface are determined, and a Reynolds stress type turbulence model is modified to account for redistribution of turbulent energy in the near-wall region of the boundary layer. The invention permits drag reduction by a coating with specified density, thickness, and complex shear modulus to be predicted for a given body geometry and freestream velocity.