Abstract: This invention relates to apparatus for the conversion of thermal energy into mechanical motion. Transducers, such as nickel-titanium alloys, are employed which change their configuration and pliancy upon the application of stimulus such as heat. In the absence of a suitable stimulus, they are pliant and easily flexed. However, when stimulated they tend to assume a prederminable configuration and then become rigid. Apparatus utilizing these phenomena convert the energy of physical transformation into useful mechanical work.Several embodiments are described. In one, the transducer is belt shaped and drivingly connected to several pulleys. Heat stimulus is applied to the belt locally adjacent at least one of the pulleys. The resultant straightening forces, inherent in an alloy such as nickel-titanium, cause rotation of the belt and hence the pulleys. In another embodiment, the transducers are opposingly connected to a reciprocating member so as to produce reciprocating motion when selectively stimulated.

Abstract: This invention embodies an intensifier cylinder assembly within the main hydraulic ram of a plastic molding machine whereby the clamping force holding the mold halves together can be increased during the shot cycle of the machine by at least three times the normal clamp force of the machine. Additionally, the location of the intensifier reduces the number of high pressure hydraulic fittings in the machine improving the safety factor while reducing the overall cost of the intensifier itself since the ram piston now becomes the housing for the intensifier piston.

Abstract: An electric power generating system in which solid material is caused to flow by gravity from an upper level to a lower level onto a wheel or a series of wheels which are caused to rotate by the weight of the material on blades spaced along the periphery of the wheels. The wheels are interconnectable and in a system which drives electrical generators to produce power.

Abstract: In a turbine driven power generating plant of the type using for example a hydrocarbon or halocarbon as the working fluid operating on or near the surface of an ocean, warm surface water is used as a source of heat for a boiler and cold water pumped from substantial depths is used to condense the working fluid after it has been expanded through the turbine. An auxiliary power source for starting the water pumps of the main system includes a prime mover driving a compressor which in turn supplies a high energy working fluid to a turbine coupled to drive the water pumps. The turbine exhaust after being cooled in a heat exchanger by the cold water pumped from the ocean depths, is returned to the suction side of the compressor.

Abstract: In a steam engine, an intermediate phase is provided for preheating the feedwater before it enters the boiler. The preheating is achieved by means of the reapplication of the otherwise dispensable exhaust steam in a simple feedback operation in which the exhaust steam is introduced directly into the feedwater. By means of electronic controls the operation of the system at the highest possible point of preheat (up to 210.degree. F.) is achieved thus assuring both high efficiency of the machine and cumulative economy in fuel consumption as well. The latter is further augmented by generous application of insulation to prevent wasteful dissipation of thermal energy as well as to effect protection of the system against the elements.

Abstract: The invention described herein pertains to a combination hydraulic thermodynamic prime mover, for the conversion of thermal energy from low-temperature heat sources, such as solar heat, geothermal steam of poor quality and waste heat of all kinds, into useful mechanical or electrical power, employing a new and novel technique of low temperature-pressure energy conversion.

Abstract: A boom is disclosed having an elongated flexible skirt confined between and secured to a series of floats arranged in pairs. The floats of each pair are identically formed, and are oppositely arranged at opposite sides of the skirt, to which they are secured in such fashion as to dispose the upper edge portion of the skirt above the water level. The lower edge of the skirt extends downwardly below the water level a suitable distance to confine pollutants, such as oil, floating upon the surface of the water. A tension member extends along the bottom edge of the skirt, in the form of a flexible cable. The tension member is retained in position through passage thereof within longitudinal bores provided in clamp assemblies regularly spaced along the length of the skirt. Each clamp assembly comprises complementary metal clamp elements, particularly shaped as to permit their being formed as extrusions.

Abstract: A method for moving a floating body into a predetermined float path which is different from that bodies natural drift path by reducing the density of the liquid in which said body is floating, the reduction in density being generally in the direction of said predetermined float path.

Abstract: This disclosure relates to an apparatus for preventing erosion of the seabed in front of a lengthy hydraulic structure with a steep face comprising a sheet of rigid or flexible material which is unapertured or perforated, and means for supporting the sheet at an acute angle to the hydraulic structure with an upper edge thereof contiguous the steep face above the seabed and a lower opposite edge portion being remote from the steep face and being positioned adjacent the seabed.

Abstract: An ecologically acceptable liquid-impermeable geologic barrier is made from shale. In the process described, the preferred shale is Brainard Shale, the upper shale formation in the Maquoketa Group, which is excavated to expose solid, unweathered shale in its original sedimentary state. The Brainard shale is removed by a suitable mining operaton and crushed into an aggregate which can be readily compacted. Water is added and the shale aggregate is thoroughly mixed to uniformly disperse the water. It is immediately spread in a layer of uniform thickness along a wall to be sealed and worked and further mixed in place and compacted solid by multiple passes of a sheepsfoot roller. This is repeated in multiple lifts until the barrier reaches a desired total compacted thickness and width.

Abstract: A mine roof support comprises at least one pair of hydraulically extensible chock legs connected at upper ends in articulated manner between one or more roof beams of the support and connected at lower end in articulated manner to one or more base members of the support, a rigid yoke located at a position spaced from the base member(s) between and connecting either the pair of chock legs, the yoke containing between the chock legs a projecting pin secured in a bearing attached to the yoke, or one of the pairs of chock legs, the yoke containing two projecting pins each pin being secured in a bearing attached to the yoke, and the or each pin having a lateral base contained at one side between abutment surfaces secured to the base member(s) and at the other to one end of a load applying means, the other end of the load applying means being supported from the base member(s).

Abstract: A work arm system for a submergible chamber wherein a plurality of work arms are rotatably mounted to the chamber and are retractably extensible, so as to provide a plurality of tools for work at a subsea station, such as an offshore wellhead station. One arm is provided with tool mounts at opposite ends, both ends being retractably extensible so that each end may alternatively be disposed to the subsea station. The present work arm system permits several work functions to be performed without resurfacing of the chamber.

Abstract: Apparatus for providing directional drilling from an offshore drilling platform, the drilling platform being of monopod construction with a submerged base, a single vertical column extending up from the base and supporting a platform above the water, the column having a vertical moon pool extending downwardly from the platform and opening in the base. A conductor pipe for receiving a drill string from a drilling rig mounted on the platform extends from the platform through the moon pool, the conductor pipe curving in an arc. The conductor pipe is supported vertically at its upper end. The conductor pipe is supported at the lower end at a position displaced from the center of the moon pool. The upper and lower supports permit rotation of the conductor pipe about a common vertical axis, the radial displacement of the lower end of the conductor pipe from this axis due to the curvature of the pipe being adjustable.

Abstract: A shoe for adjustably supporting a pipeline relative to a ramp of a lay vessel is comprised of a cradle which supports the pipeline in longitudinally movable relation with the ramp. The cradle contacts the pipeline intermediate the longitudinal axis of the pipeline and the surface of the ramp. An elongated lever is pivotally connected at one extreme to the ramp and at another extreme to the cradle. The elongated lever is rotated by rotating means about the pivotal connection with the surface of the ramp to alternately raise and lower the cradle and thereby adjustably support the pipeline relative to the ramp.According to the method of the invention, a pipeline can be adjustably supported relative to a ramp of a lay vessel by first cradling the pipeline above the surface of the ramp in longitudinally movable relation therewith. This step may be accomplished by a cradle having two degrees of freedom relative to the ramp and pivotally connected thereto through an elongated lever.

Abstract: A reversible compression type refrigeration system is commonly known as a heat pump for conditioning a space having a conditioning side and a service side. The conditioning side is that area or environment where it is intended to achieve the benefit of the alternate heating and cooling effects produced by the reversible system. The service side is that side from which heat is drawn or to which heat is rejected when the opposite effect is required on the conditioned side.

Abstract: An air conditioner for use in a vehicle having a gasoline engine with a fuel intake providing a source of reduced pressure. The air conditioner includes a gasoline vaporizer in which gasoline from the fuel system of the vehicle is vaporized and drawn through a heat exchanger for cooling purposes. There is a blower for blowing air across the heat exchanger to cool the air for circulation in the vehicle. The vaporized gasoline passes through a separator for separating excess gasoline from the mixture, and also passes through a proportioning device connected to the fuel intake of the engine for adjusting the fuel-to-air ratio at the fuel intake to optimize combustion and control pollution.

Abstract: Preservation of biological materials is accomplished by apparatus and a process with and by which the material is cooled at a substantially linear rate to approximately freezing temperature, changed from the liquid to the solid phase at relatively constant temperature, and cooled at a substantially linear rate to an end temperature. The environment surrounding the material is rapidly chilled when the material reaches freezing temperature or a temperature minimally warmer than freezing temperature in the liquid phase to initiate phase change with minimal risk of super cooling the material, and is then warmed to freezing temperature or a temperature minimally cooler than freezing temperature to minimize temperature drop in the material upon completion of phase change. The apparatus contemplates, among other things, preselection of cooling rates, duration of phase change, and the end temperature.

Abstract: A reverse cycle heat pump is provided with a heat exchanger which provides refrigerant subcooling with no thermodynamic losses. The heat exchanger is arranged such that it is operative only during the heating cycle to permit optimum charging of the system and allow operation during the cooling cycle with no excess refrigerant in the system accumulator. The heat exchanger is bypassed when the system is converted from heating to cooling operations.Liquid refrigerant will be mixed with oil in the accumulator during the heating cycle, but not the cooling cycle. Then since refrigerant liquid returning with the oil from the accumulator to the compressor should be evaporated to avoid harm to the compressor, heat applied to the suction line, with no thermodynamic loss, vaporizes this refrigerant. During the cooling operation, no liquid refrigerant is returned from the accumulator, so heat added to the suction gas would be undesirable.

Abstract: A three stage passive cooler for use in a spacecraft for cooling an infra-red detector includes a detector mounting cold plate for mounting the detector directly to the telescope optics. The telescope optics collect and direct the infra-red radiation from the earth, for example, to the infra-red detector, and are mounted directly to the spacecraft. The remaining stages of the cooler are mounted with thermal insulators to each other and to the spacecraft at separate locations from the detector mounting cold plate.

Abstract: An artificial ornamental stone of cabochon shape comprising a transparent light or yellowish brown matrix in which are embedded parallel to the base of the stone transversely orientated parallel fibers with greenish yellow transparent cores having a selected index of refraction clad in transparent sheaths which may be defined by the matrix and have an index of refraction less than the cores. In producing the base material for the stone, the fibers may be clad in one or more sheaths and embedded in the lower melting point matrix or the fibers may be unclad or partially clad and mixed with lower melting point and lower refractive index fibers and the assembly fused into an integral mass. The stone may be covered with a thin colorless, transparent, hard protective coating.

Abstract: A stabilizer for use on circular knitting machines for maintaining alignment between the cylinder and dial during circular knitting of a fabric having a longitudinally extending strip of float yarns between the beginning and end of circularly knit rows of stitches, the stabilizer including a first roller mounted for rotation on the cylinder against one side of the longitudinally extending strip of float yarns, a second roller in mating engagement with the first roller and mounted for rotation on the dial against the other side of the longitudinally extending strip of float yarns and in mating engagement with the first roller and means for driving one of the rollers for feeding the float yarns in the strip between the rollers as the float yarns are engaged between the rollers.

Abstract: This invention is relative at domestic knitting machine consisting of at least one needle board supporting slidingly in grooves the knitting needles and a movable carriage parallel above the needle board, the carriage being provided with a lock fitted with an electromagnetic needle selection component, which machine is characterized in that the electromagnetic component is mounted on the lock with the aid of a guiding means ensuring free movement in a direction substantially perpendicular to the plane of the needle board.

Abstract: Decatizing apparatus comprises a steaming cylinder and a suction cylinder. Respective primary backing cloths are associated with the steaming and suction cylinders to press the fabric to be treated against the cylinders, the tension of each primary backing cloth being adjustable independently of the other backing cloth. An intermediate backing cloth is interposed between each primary backing cloth and the fabric in the zone of the cylinder, and moves over the cylinder with its associated primary backing cloth without slipping. The intermediate backing cloths permit the use of high surface pressures to be applied by the primary backing cloths.

Abstract: A padlock is disclosed having an outer case preferably of hardened steel and having no shackle or bow which can be sawed or broken off. The case has an opening for insertion of a staple and has a slide bolt which extends through the opening to engage the staple. The slide bolt is secured by a locking means which includes a lock sleeve located within a cylindrical bore in the case, the sleeve being movable between a locked position and an unlocked position. The slide bolt is attached to the sleeve and extends through the opening when the sleeve is in the locked position. The lock sleeve has a retractable locking member projecting from a hole in the wall of the sleeve. The locking member is capable of fitting within an indentation in the interior bore wall when in the locked position to hold the sleeve in the locked position and capable of retracting into the hole to free the sleeve when in the unlocked position. A lock cylinder is fixedly mounted within the shell.

Abstract: A locking cap for the gasoline tank of a automotive vehicle, having an electrically actuated device for unlocking the cap, the unlocking device having an operative electrical circuit including an electrical switch actuated by the ignition key of the vehicle. The switch can be closed only at a position of the key corresponding to an "engine-off" condition, so that the cap cannot be unlocked with the engine running. The unlocking device includes a hammer-blow apparatus for assisting in the opening of the cap in the event it should be frozen shut.

Abstract: A lock plate assembly that mounts about a pair of transmission gear shift levers of a vehicle to prevent unauthorized use of the vehicle. The lock plate assembly consists of a pair of shaped plates which are shaped to matingly engage with each other, with each plate shaped to fit halfway about two parallel cylindrical rods. An accessory assembly may be mounted to the vehicle floor to permit mounting the lock plate assembly about a shaft on the accessory plate and about one transmission gear shift lever of a vehicle, when so desired.

Abstract: A locking hardware adapted to conceal and confine the clamp screws of an outboard motor against operative removal from the transom board of a boat and the like by the provision of a back plate set against the transom board by the clamp screws and having a stud bolt parallel to the clamp screws and inboard arm of the C clamp of the motor upon which stud bolt a channel iron cover member is mounted to confine the handles of the clamp screws, the cover member having a cylindrical shell aligned with the threaded end of the stud bolt for receiving a wrench operated nut therein for securing the cover member to the bolt and lock receiving keyway in the wrench head of the nut for locking such nut within the cylindrical shell to prevent removal of the nut therefrom.

Abstract: A mechanical lock comprises a cylindrical stator, a main rotor constituting the lock cylinder and being mounted for rotation in the stator and an auxiliary rotor mounted in the main rotor. A key carrying information can be inserted into the keyhole of the main rotor and turned to rotate the same between angular positions corresponding to an open and closed lock position through an intermediate latched position. A differential drive couples the auxiliary rotor to the main rotor for effecting relative rotational movement thereof. Key information sensing elements sense the key information during the relative rotational movement of the auxiliary rotor and are repositioned thereby, and these elements are taken along by the main rotor rotation at the end stage of the relative movement to remove them from contact with the key and return them to a rest position.

Abstract: Gage control apparatus and methods for tandem rolling mills are disclosed which are based on the low of constancy of mass flow. The apparatus and methods are attained by the discovery of the fact that the forward slip ratio of a mill stand varies as a linear function of the reduction ratio particularly when a plate material is rolled under relatively low tension. A ratio between thicknesses of the plate at the output and input sides of a particular stand of the tandem rolling mill and a ratio between circumferential speeds of rolls of the adjacent stands are used to calculate a thickness of the plate at the ouput or input side of each of the stands other than the particular stand. Each of the stands other than the particular stand is adjusted in its roll gap in accordance with a deviation of the calculated thickness from a desired thickness so as to cancel the deviation.

Abstract: A spring coiling machine with an improved drive means has a pair of feed rolls for advancing wire from a source of supply to a coiling station. Coiling tools at the station obstruct feed movement and form coil springs and a cut-off tool successively severs the springs. The coiling tools and cut-off tool are operated from a camshaft driven by a first electric motor and a second electric motor drives the feed rolls. Continuous rotation for both camshaft and feed rolls is provided by the electric motors and a mechanism operated by the camshaft lifts an upper feed roll to terminate feed roll gripping action on the wire and to thus terminate wire feed at the completion of each spring. The first or camshaft motor serves as a lead motor and the feed roll motor as a follower. A digital feedback from the first motor is introduced to the control system therefor and also as an input to a second control system for the feed roll motor.

Abstract: The invention concerns a process and device for carrying out the process for the provision of continuous lubrication of the working surface of an extrusion die. The surface of the extrusion billet is lifted locally from the die surface during extrusion and the lubricant is introduced into the resultant dead space and from there onto the surface of the billet, the working surface of the die and throughout the die as extrusion progresses.

Abstract: A device for electrical discharge forming comprises a fixed plate upon which is mounted an explosion chamber. Said chamber accommodates an electrode while its wall serves as the other electrode. To set off an explosion, the electrodes are electrically connected by a wire fed into the explosion chamber through a hole in its wall, said hole being made in the area of a step formed in the chamber wall. Installed near this hole are two knives one of which is rigidly fixed while the other one is movable for approaching the first knife and cutting off the wire. The cut-off end of the wire comes to rest on said step. In the device according to the invention the end of the wire does not stick to the hole in the chamber wall which eliminates the necessity of the operator cleaning the hole before feeding a fresh piece of the wire into the chamber.

Abstract: The invention concerns an apparatus for forming annular circumferential corrugations in the end of a helically corrugated seamed pipe. Two corrugating rolls, a backup roll and a thrust roll, engage the wall of the pipe to form the annular corrugations. The backup roll normally engages the inner wall of the pipe, and the thrust roll, the outer wall. The thrust roll is formed from a plurality of independent and transversely movable roll sections urged with a predetermined force into engagement with the pipe by a support composed of a group of rolls engaging the periphery of a corresponding roll section and mounted within a pivotable lever frame. The predetermined force is provided by a pressure-controlled hydraulic cylinder acting through each of the lever frames.

Abstract: A knurling tool having three knurling wheels adapted to be positioned about a workpiece to be knurled and in which one of these knurling wheels is mounted on a movable block which is adjustably positionable against the workpiece. A quick release mechanism is included which will release the workpiece without affecting the relative working position of the knurling rollers.

Abstract: A straightening machine for straightening elongated workpieces at high speed comprises a plurality of stands or frames mounted on a machine bed displaceable with respect to each other in the direction of the movement of the workpieces. Each stand comprises a cage provided with a set of four straightening rolls rotatable about the axis. Each cage is mounted on a cage holder on a guide adjustable in radial direction with respect to the workpiece axis and the guides on the plurality of stands are located in parallel planes normal to the workpiece axis, with the guides on successive stands extending normal to each other as viewed in the direction of movement of the workpiece through the machine.

Abstract: The method of gaplessly separating and identifying successive rolling lots of ingots or blooms in a production process for making tubes or the like wherein the stock is introduced into a furnace for heating and in a production line subsequently rolled, which comprises radio-actively marking the first or the last ingot of a given rolling lot of ingots at its subsequently lost end prior to being introduced into the furnace. A further step includes interposing a radio-active radiation responsive signal device in said production line before rolling. Apparatus for carrying out said method includes a device for imparting radioactivity to an ingot in advance of a rotary hearth furnace. Radiation counter-tubes are located in advance of a taper mill and a continuous rolling mill respectively. Further counter-tubes are arranged in advance of a stretch reducing or sizing mill.

Abstract: A process for the manufacture of composite sections comprising at least two components. This is achieved by means of extrusion in particular using a light metal matrix, whereby at least one insert or similar component is fed into the stream of metal being extruded, on each side of the main axis in the region of the extrusion die bearing and covered all over with light metal as a result of pressure from all sides.

Abstract: A support has spaced ends and a longitudinal passage which extends intermediate these ends. A carriage is mounted for movement in and lengthwise of the passage, and a drive is provided for moving the carriage. At least one first tool holder is provided on the carriage, and a mounting arrangement is located at one or both of the ends for mounting additional tool holders.

Abstract: Hydraulic overload protection device for a press comprises a housing receiving therein a piston defining with this housing a space communicating via a check valve with a supply source and via a relief valve with a drain. This space additionally communicates with the drain via a line including an adjustable relief valve and a device for disconnecting the said space from the drain, when the movable member of the press, carrying a die, has been driven through the maximum length of its stroke. The disclosed protection device offers fine adjustment of the pressing or stamping effort and prolongs the service life of dies.

Abstract: Pickups for the measurement of the accuracy of electronic timepieces are closed. The pickups each include an induction-winding detector and an integrated-circuit frequency divider which is the same as the integrated-circuit frequency divider of timepieces to be measured therewith. The pickups are useful as accessories for chrono-comparators which are normally used to measure the accuracy of mechanical, or sonic, frequency timepieces. Individual ones of these pickups are used to test timepieces of different frequencies by a simple substitution of pickups.

Abstract: An apparatus for testing the accuracy of a timepiece comprising a television camera for converting the time displayed into an electrical signal, a means for converting the electrical signal into a digital signal, and a processing means for storing the digital signal and comparing the digital signal to a signal corresponding to a time standard. In operation, the time displayed on the timepiece is compared to the time standard at two different times and the difference between the time standard and the time displayed of the two measurements is compared.

Abstract: An impact impulse measuring device comprises an acceleration transducer which converts the mechanical oscillations of the object being tested into electric signals which are applied to an amplifier unit which is electrically coupled to a means for measuring the parameters of an impact impulse via a means for automatically switching the range of measuring impact impulse parameters. The means for measuring parameters of an impact impulse includes a comparator connected to one of the inputs of a digital-analog converter and a reference voltage source connected to another input of the digital-analog converter, the digital-analog converter having its third input connected to a high-frequency pulse generator.

Abstract: A semiconductor article suitable for use in the detection of hydrogen gas in the atmosphere. The article comprises a film of palladium deposited onto a semiconductor film of stannic oxide which is positioned on a suitable substrate together with a resistance heating element. In some cases, the stannic oxide film is provided with a dopant to improve the operation of the article.

Abstract: A fluid application device suitable for applying small quantities of blood to a microscope slide is described. The device has a housing within which a longitudinal aperture is formed. At one end of the aperture a transverse groove is formed which intersects the aperture. Small quantities of blood from a capillary tube may be introduced into the longitudinal aperture and permitted to spread through the transverse groove so that a relatively thin and uniform layer of blood is deposited on a microscope slide by drawing the device across a microscope slide.

Abstract: An acoustic microscope for scanning an object stereo-optically and with both dark field and light field imaging. The microscope focuses acoustic waves on a focal point and moves the object in a planar raster pattern through the focal point. The acoustic waves are modulated by the object and displayed on an oscilloscope. The microscope permits the rotation of the object about the focal point so that two, azimuthally displaced images of the object can be obtained. These two images can be observed as one three-dimensional image in a lenticular stereoscope. In addition, the microscope can scan the acoustic waves scattered by the object and display a dark field image of the object.

Abstract: An apparatus for providing an ultrasonic sectional view stating the proportion of meat and lard in biological material. The apparatus comprises a transducer unit and an ultrasonic pulse generator providing a periodically scanning window. Said transducer unit comprises at least two multi-crystal units, the longitudinal axes of which may form a variable angle. The joint between the multi-crystal units comprises an angle information unit. By means of said angle information unit and the means for visualizing reflected ultrasonic echoes it is possible to visualize marginal surfaces.

Abstract: An apparatus for providing an ultrasonic sectional view of a body to be examined. The apparatus comprises a transducer head in the form of a wheel in the periphery of which four ultrasonic transducers are built in. The wheel rotates about an axis perpendicular to the sectional plane. The apparatus further comprises means for separately and successively cutting the transducers in and out of a pulse circuit in such a manner that each transducer covers only a sector from -45.degree. to +45.degree. with regard to a symmetry axis for the transducer head.

Abstract: A device and method for determining strength properties of a subterranean formation. The device is insertable into a borehole formed in the formation, and includes a pair of inflatable semi-cylindrical members mounted on a shaft. The inflatable members when pressurized exert radial force in all directions except along the plane between the members, with the result that a higher parting force is exerted on the formation perpendicular to the plane between the members than across any other plane through the axis of the device.

Abstract: A transducer including four pins arranged at the corners of a square and provided with exciting and sensing windings are fixed either to the surface of a body of magnetic material to measure stresses therein or to a plate of magnetic material fixed to the body where the body is of non-magnetic material or has undesirable magnetic characteristics.

Abstract: A biaxial capacitance strain transducer in the form of a laminated structure defining two capacitance strain transducers in orthogonal orientation. Each capacitance strain transducer comprises driven capacitance plates which are excited by an oscillator and a sensing capacitance plate disposed in spaced parallel relation to the driven capacitance plates. A shutter mechanism in the form of a pair of apertured plates is provided between the driven plates and the sensing plates. The ends of the apertured plates extend out of the laminated structure and are attached to the surface wherein strain is to be measured. Strain will produce relative displacement of the apertured plates, resulting in variation in the capacitive coupling between the sensing and driven plates through the apertures. This differential capacitance, which is thus related to the strain to be measured, is detected and measured by suitable electronic instrumentation.