Abstract: The control of the pressure supply to a piston-cylinder unit (10) is effected by monitoring the pressure in the corresponding line (16) through a pressure sensor (22). This pressure is measured in fixed time intervals and the changes in pressure are determined. When the change in pressure has become zero, it is detected that the set terminal pressure has been reached so that the working operation is ended. A switching to the return stroke is effected when the pressure increase in at least one time interval is greater than in at least one of the previous intervals of the working operation. The control is independent from the type of piston-cylinder unit employed and requires no sensors at the piston-cylinder unit.

Abstract: An electro-hydraulic steering control system for directing fluid to steering actuators on a work machine may include a main valve configured to control fluid flow to the steering actuators. Left and right primary steering valves may be in communication with and configured to affect the main valve to control fluid flow to the steering actuators. Left and right redundant steering valves may be in communication with and configured to affect the main valve to control fluid flow to the steering actuators. A shuttle valve may be operably disposed between one of the right primary and the right redundant steering valves and the left primary and left redundant steering valves. The shuttle valve may be operable to selectively control fluid from the one of the right primary and the right redundant steering valves and the left primary and left redundant steering valves to the main valve to control the main valve.

Abstract: A control system for a Stirling engine including the use of a synchronous power converter (“SPC”) which is connected to the terminals of the alternator in a linear alternator/FPSE power system. According to the teachings of the present invention, the attached SPC is small and portable and further ensures that piston and displacer excursion within the system remain within design limits. The system and method are designed such that it is possible to adjust both the voltage amplitude and the waveform frequency at the terminals of the linear alternator. By controlling these operational aspects, both the speed and the range of travel associated with the piston and the displacer in the FPSE can be controlled.

Abstract: A control system and method for increasing engine temperature for an engine having a variable nozzle turbo (VNT) is provided. An offset idle module generates an offset idle signal. A normal boost module calculates a normal boost. A supplemental boost module calculates a supplemental boost. An offset boost module generates an offset boost signal for the VNT based on the normal boost and the supplemental boost. A control module adjusts engine idle and VNT boost based on the offset idle signal and the offset boost signal.

Abstract: The invention is a system and method for smoothly starting and controlling an ORC power plant. The system comprises a cascaded closed loop control that accounts for the lack of relationship between pump speed and pressure at startup so as to control pump speed and pressure, and that smoothly transitions into a steady state regime as a stable operating condition of the system is attained. The cascaded loop receives signals corresponding to a superheat setpoint, a pressure at an evaporator exit, and a temperature at an evaporator exit, and controls the pump speed and pressure upon startup to provide smooth operation. The system and method can further comprise a feed-forward control loop to deal with conditions at start-up and when external disturbances are applied to the ORC power plant.

Abstract: A gas turbine system (100) includes a compressor (110) for receiving air and producing compressor discharge air, a combustor (120) for combusting an oxygen comprising gas flow including the discharge air and a fuel into a hot gas flow, and a turbine expander (130) generating output power from the hot gas flow and providing a hot exhaust gas flow. An extractor (135) is provided for splitting the discharge air into a direct flow portion (121) which directly reaches the combustor (120) and an indirect flow portion (122). A mixing device (140) receives the indirect flow portion (122) and mixes it with a water flow (145), either in the form of water or steam, to produce a water enhanced indirect flow portion (150). A recuperative heat exchanger (155) heats the water enhanced indirect flow portion (150) using heat from at least a portion of the hot exhaust gas flow. The heated water enhanced indirect flow portion (158) is then reintroduced into the oxygen comprising gas flow.

Abstract: A gas turbine combustor has a combustion chamber into which fuel and air are supplied, wherein the fuel and the air are supplied into said combustion chamber as a plurality of coaxial jets.

Abstract: An aircraft engine comprising a nacelle, a first wall and fan outlet guide vanes. The fan outlet guide vanes comprises a plurality of stator vanes extending between a second wall and a third wall. The nacelle having apertures at a region of low pressure. A means to bleed fluid from a region of high pressure at one or more of the first wall, the second wall, the third wall or the stator vanes and at least one duct to connect the means to bleed fluid from the region of high pressure to the at least one aperture in the nacelle. The static pressure at the high pressure region is greater than that in the low pressure region such that at least some of the boundary layer of the fluid flows through the at least one duct to the at least one aperture in the nacelle.

Abstract: The invention relates to heating engineering. The inventive method for heating or cooling fluid medium consists in supplying a cooled or heated fluid medium in a through channel and in subsequently heating or cooling said fluid medium therein at least in two stages. Said through channel is divided into heating and cooling stages having the same length. The temperature of each stage increases in the case of heating and reduces in the case of cooling stepwisely and directly proportionally in a direction away from the thirst stage to the next stage. The heated or cooled water is supplied to the through channel tangentially at an angle of 45–90° to the generatrix of the internal surface thereof at a point where the fluid medium is introduced. Said invention increases the efficiency of the process of heating or cooling said fluid medium.

Abstract: A resonant linear motor driven cryocooler system, particularly suited for providing refrigeration to a magnetic resonance imaging system, wherein vibrations from the resonant linear motor and noise from pulsed gas are isolated from the cryocooler by work transfer piping comprising connecting tubing and preferably a dashpot, and wherein the connecting tubing has a volume which exceeds the internal stroke volume of the resonant linear motor.

Abstract: In combination, pressurized fluid contained in a storage vessel, in both liquid and vapor regions, a heat exchanger in the vapor region of the vessel, and a first pressure regulator having an inlet side in communication with liquid in the vessel, and having an outlet side in communication with the heat exchanger, whereby if pressure in the vessel rises to the setting of the regulator, it opens and admits liquid from the vessel to the heat exchanger, to vaporize in that exchanger causing vapor in the vessel to condense, and reducing pressure in the vessel.

Abstract: A magnet vent assembly for venting a cryogenic gas from a superconducting magnet of an MRI system. The assembly comprises: a first burst disc, the first burst disc comprising a first inlet and a first outlet; a second burst disc, the second burst disc comprising a second inlet coupled to the first inlet and a second outlet coupled to the first outlet; and wherein the magnet vent assembly is configured to switchably direct a flow path of cryogenic gas through either of the following: the first burst disc and the second burst disc. A service tool for a magnet vent assembly for venting a cryogenic gas from a superconducting magnet of an MRI system. The magnet vent assembly comprises a first burst disc.

Abstract: The pulse tubes (165, 175) and regenerators (160, 170) contained within a cryopump housing (210) are arranged in a way that facilitates the fabrication and installation of the cryopanels (265). The pulse tubes and regenerators are located in a common plane in the center of the cryopump housing and the cold (second stage) panels (265) that are pitched parallel to the plane with the tubes.

Abstract: A water dispenser for a refrigerator freezer having a water dispensing control including a measured fill mode of operation in which the water dispenser dispenses a predetermined amount of water and a manual fill mode of operation. The water dispensing control allows user selection of the units of measure, the type of container being filled and selection of the amount to be dispensed. A user display can display the selections and can display the amount dispensed in real time.

Abstract: A real-time monitoring system that monitors various aspects of the operation of a refrigerant-cycle system is described. In one embodiment, the system includes a processor that measures power provided to the refrigerant-cycle system and that gathers data from one or more sensors and uses the sensor data to calculate a figure of merit related to the efficiency of the system. In one embodiment, the sensors include one or more of the following sensors: a suction line temperature sensor, a suction line pressure sensor, a suction line flow sensor, a hot gas line temperature sensor, a hot gas line pressure sensor, a hot gas line flow sensor, a liquid line temperature sensor, a liquid line pressure sensor, a liquid line flow sensor. In one embodiment, the sensors include one or more of an evaporator air temperature input sensor, an evaporator air temperature output sensor, an evaporator air flow sensor, an evaporator air humidity sensor, and a differential pressure sensor.

Abstract: The automatic ice making device includes ice sensor for detecting ice-making in ice chill tray, heater for heating ice to separate the ice from ice chill tray, motor rotating discharging member for discharging ice from ice chill tray, position detecting switch for detecting rotating position of discharging member, ice storage amount detecting switch for detecting overs and shorts of discharged and stored ice, water supply valve for supplying water to ice chill tray, and controller for controlling electric conduction to heater and motor. When power supply to controller is once interrupted and re-started, ice storage amount detecting switch detects shortage of ice so as to hold motor not to drive until ice sensor detects temperature below a predetermined temperature.

Abstract: A vapor compression system includes a main vapor compression circuit having a compressor, a condenser, an expansion device and an evaporator serially connected by main refrigerant lines, the compressor having a suction port, a main discharge port and an intermediate port, and the main refrigerant lines being communicated with the main discharge port and the suction port; a bypass circuit communicated between the intermediate port and the suction portion; and a superheat sensing device positioned to sense superheat in a combined flow from the main vapor compression circuit and the bypass circuit. A method of operation of the system is also provided. The benefits of enhanced system and compressor performance, improved compressor reliability and extended system operating envelope are readily obtained.

Abstract: There is provided a cooling apparatus which can improve a cooling efficiency while preventing an abnormal increase in pressure of a high side. The cooling apparatus comprises: a refrigerant circuit which uses carbon dioxide as a refrigerant; a control device which controls a speed of rotation of the compressor between predetermined lowest and highest speeds; and a cooled state sensor which detects a cooled state in a refrigerator main body to be cooled by an evaporator included in the refrigerant circuit. The control device increases a highest speed of rotation of the compressor if a temperature in the chamber of the refrigerator main body detected by the cooled state sensor is low.

Abstract: In a compressor control system for a vehicle air conditioner, a hybrid ECU of the vehicle controls a rotation speed of a compressor electric motor. In this case, an output circuit, which outputs a driving signal for driving the compressor electric motor, only needs to be newly provided in the hybrid ECU when a hybrid vehicle or an electric vehicle is manufactured based on an engine vehicle. Therefore, a high cost is not caused even when the output circuit is provided in the hybrid ECU which should be newly designed and manufactured. In addition, because the output circuit does not need to be provided in an air-conditioning ECU which is an existing component of the engine vehicle, the air-conditioning ECU in the engine vehicle can be directly applied to that in the hybrid vehicle without a substantial hardware change. Therefore, design cost can be reduced.

Abstract: An integrated noise and heat management system for the management of noise and heat around a heat and noise source is described. The system includes an enclosure for surrounding the heat and noise source, the enclosure having a double wall structure defining an air space within the double wall structure. The double wall structure contains a heat exchange system in heat exchange contact with the air space and the heat source that enables the transfer of heat from the air space to the exterior of the enclosure and is doubly effective in attenuating noise from the noise source to the exterior of the enclosure.

Abstract: A liquid cooling system utilizing minimal size and volume enclosures, air pockets, compressible objects, and flexible objects is provided to protect against expansion of water-based solutions when frozen. In such a system, pipes, pumps, and heat exchangers are designed to prevent cracking of their enclosures and chambers. Also described are methods of preventing cracking in a liquid cooling system. In all these cases, the system must be designed to tolerate expansion when water is frozen.

Abstract: Disclosed is an air conditioning apparatus with two adsorption elements (81, 82). The air conditioning apparatus repeatedly alternately performs a first operation in which air is dehumidified by the first adsorption element (81) simultaneously with regeneration of the second adsorption element (82) and a second operation in which air is dehumidified by the second adsorption element (82) simultaneously with regeneration of the first adsorption element (81). At the time of switching between these operations, only the flow path of air is changed, with the adsorption elements (81, 82) remaining stationary. The air conditioning apparatus includes a refrigerant circuit. The refrigerant circuit performs a refrigeration cycle in which a regenerative heat exchanger (92) operates as a condenser and either one of first and second cooling heat exchangers (93, 94) operates as an evaporator.

Abstract: An ice-maker for producing transparent ice cubes has a refrigerating assembly, an ice cube making tub, and a feeding tank for filling the ice cube making tub in a common housing. The ice cube making tub is movable between a first position, wherein cooling fingers of the refrigerating assembly engage into the ice cube making tub, and a second position away from the cooling fingers.

Abstract: An ice cube making machine having an evaporator assembly on which ice is formed. The evaporator assembly is constructed using micro-channel tubing that provides several channels for the flow of refrigerant within the channels. Liquid refrigerant flowing through the channels causes ice to form on the outer surfaces of the micro-channel tubing over which water flows. Refrigerant vapor is circulated through the channels to release the ice cubes from the micro-channel tubing of the evaporator assembly.

Abstract: A refrigerant supply apparatus for supplying a refrigerant to a cooling target. The apparatus includes a refrigerant supply channel through which pure water as the refrigerant is supplied to the cooling target, an impurity removing unit disposed in an impurity removing channel which is a channel different from the refrigerant supply channel, a sensor which measures a purity of the pure water, and a valve which stops supply of the pure water to the cooling target when the purity of the pure water does not satisfy a predetermined standard.

Abstract: The refrigerating unit can be operated by means of a thermal solar system as energy source. Therein it is provided that the refrigerating unit is formed as a diffusion-absorption refrigerating unit. The refrigerating unit has an expeller, a triple heat exchanger, a condenser, an evaporator, a gas heat exchanger, an absorber, and a fuel reservoir which are actively connected to form a closed fuel circuit with one another.

Abstract: The invention relates to a process and apparatus for delivering an ultra high purity fluid comprising at least one component to a point of use at a required pressure without mechanical pumping. In one embodiment, a high purity feed comprising at least one component in gaseous or liquid form is charged into a vessel and at least partially converted to a solid phase source. As the feed is converted to a solid phase source, additional feed may be added until the vessel is at least substantially filled with a solid phase source or slush. Once filled, the solid phase source or slush may be isochorically heated whereby the solid phase source is converted to a product at an elevated pressure.

Abstract: A method of separating one or more light components, such as helium, from a carbon dioxide containing stream. A two-phase stream is obtained, at least in part, by cooling a pressurized feed stream to at least partially condense such stream. The stream that is subsequently degassed to produce a first vapor stream enriched in the light component(s) and a first liquid stream containing an entrained fraction of the light component(s). The first liquid stream is expanded to create another two-phase stream that is degasified to produce a second vapor stream that is also enriched in the light component(s) and a second liquid stream having an enriched carbon dioxide content. The second liquid stream is repressurized and vaporized. In case of a supercritical feed, the pressurized feed stream is expanded after having been cooled. Thereafter, the feed is degassed to produce the light component enriched vapor stream and a liquid stream enriched in the carbon dioxide.

Abstract: A band that may be utilized for a timepiece, such as a watch, is disclosed. The band may have a plurality of joined links, and each link includes a cover member, an extension element, a first springbar, and a second springbar. The extension element defines a first channel and a second channel, the first springbar extends through the first channel to secure the extension element to the cover member, and the second springbar extends through the second channel to join the extension element to an adjacent cover member. In addition, the cover member is configured to join with an adjacent extension element that is separate from the extension element.

Abstract: Jewelry articles having magnetic elements and interchangeable settings are disclosed. In one aspect, the jewelry articles include magnetically coupling body portions and interchangeable settings. The body portions magnetically couple together to hold the interchangeable settings. For example, the body portions can magnetically couple together using rare earth magnets to form a composite ring. Preferably, at least one of the body portions is rotatable to tangentially break the magnetic coupling between the body portions to interchange the setting. In another aspect of the present invention, magnetic elements are used to magnetically suspend a movable setting on a jewelry article. An longitudinal member has at least one end connected to the jewelry article. The setting is movably disposed on the longitudinal member. A first magnetic element adjacent an end of the longitudinal member magnetically repels a second magnetic element on the setting.

Abstract: Methods of reducing the intrusions or migrations of photolithography materials by introducing a sol-gel layer onto a porous thin film prior to applying the photolithography/photoresist material layer. Curing the sol-gel layer results in the sol-gel layer merging or unifying with the underlying porous thin film layer so that the combined sol-gel/thin layer exhibits substantially the same properties as the untreated porous thin film layer before the sol-gel was applied. As a result, a greater etching accuracy is achieved.

Abstract: When bringing pins (2) are engaged with the yarn carrier at the engagement portions (3a, 3b) near the center of the yarn carrier, the yarn carrier, as a normal carrier, feeds the yarn so that the yarn is applied to a knitting needle performing knitting operation by a carriage. When the bringing pins (2) are engaged with the yarn carrier at the engagement points (4a, 4b) near the rear side thereof in the travel direction, the yarn carrier, as an inlay carrier, feeds the yarn in preference to the knitting operation so that the yarn is not applied to the knitting needle performing the knitting operation by the carriage. When the projection portions (6a, 6b) of engagement releasing members (5a, 5b) are pressed by the contact thereof with the stopper, the engagement releasing members (5a, 5b) are moved backward, and slope portions (7a, 8a; 7b, 8b) push up the bringing pins (2) engaged with the yarn carrier at the engagement points (3a, 4a; 3b, 4b) so as to release the engagement.

Abstract: A fabric article useful for the cushioning surface of a car seat and like items is formed from thick main elastic yarn which is thicker than main stitch yarn, and main inserted yarn which is more bulky and thicker than the main elastic yarn in apparent thickness, are knitted in line in the knitting width direction or in the knitting length direction of a mesh-like base knitted fabric which is knitted up with main stitch yarns by using a warp knitting machine and which have openings which are larger than the needle loops formed from the stitch yarn and extend over plural knitting courses.

Abstract: A golf club securing mechanism includes a rigid member and a flexible member. The flexible member is wovenly engaged with the rigid member to define one or more golf club holding regions between the flexible member and the rigid member. The flexible member can be manipulated to vary a size of the one or more golf club holding regions such that in a loose position a golf club can be positioned within one of the golf club holding regions and in a tightened position the golf club is tightly fixed between the rigid member and the flexible member.

Abstract: A dual-lock type padlock includes a number lock module that is locked and unlocked by a user, and a key lock module that is unlocked by a specific key held by an inspector of the customs for checking the luggage locked by the padlock. Thus, after the key lock module is unlocked, the identification zone of the identification member is exposed outward from the window of the housing, so that the user only needs to see the window to judge if the padlock has been opened by the customs for checking the luggage without having to open the luggage locked by the padlock, thereby greatly saving the time for checking the luggage.

Abstract: A security device is provided for locking a closure such as a door or a gate to an enclosure. The security device is a lock guard for a padlock having a shackle insertable in either a vertical opening or a horizontal opening in a latch component on the closure or the enclosure. The lock guard has a sloping roof for deflecting sledge hammer blows. The sloping roof is preferably a double pitch roof. One embodiment of the invention has two double pitch roofs facilitating its use with both latch parts having vertical openings and latch parts having horizontal openings. Another embodiment of the invention has a single pitch roof.

Abstract: A lock guard is provided which is particularly well suited to protect a padlock employed to secure a stanchion lever securing one or more doors of a cargo container, trailer truck or moving van. The lock guard includes an interior locking tab with a vertical opening through which a hinged leg of a padlock shackle extends when the unhinged leg of the shackle is passed through an opening in a component of the stanchion door and the shackle is closed by abutting it against an abutment on the underside of the roof of the guard. The lock guard, which provides a protective housing or shield for the shackle of the padlock when the padlock is in its installed locking position, is particularly compact thereby minimizing access of cutting tools to the padlock shackle.

Abstract: An apparatus which inhibits the theft of equipment such as personal computers is disclosed. The equipment must have an external wall provided with a specially designed, approximately rectangular slot having preselected dimensions. An attachment mechanism includes a housing for a spindle having a first portion rotatable within the housing, a shaft extending outwardly from the housing, and a crossmember at the end of the shaft having peripheral dimensions closely conforming to the internal dimensions of the slot. An abutment mechanism also emanates from the housing, and is located on opposite sides of the shaft intermediate the housing and the crossmember. The peripheral cross-sectional dimensions of the abutment mechanism and the shaft in combination closely conform to the dimensions of the slot. The length of the shaft from the housing to the crossmember is approximately equal to the thickness of the external wall of equipment.

Abstract: A gate lock device with front and rear units to be mounted on opposite sides of a structure associated with the gate and against which the gate closes. A gravity latch, displaceably mounted in the housing of the front unit, is engageable with a keeper pin. The front and rear units are provided with key-operated locks which are operable to lock and unlock the gravity latch. The rear unit includes an axially displaceable actuator operable to unlock the gravity latch when the key-operated locks are unlocked.

Abstract: A flange forming process uses first and second stages. The first stage produces a partially formed flange on an article. The second stage forces the partially formed flange into a die so a stepped surface of a knockout punch that is disposed in the die, produces a predetermined can height such as the FFCH (Factory Finished Can Height) while the retaining die limits the outside diameter of the flange.

Abstract: A metal sheet-receiving system for receiving parts and feeding a metal sheet-folding machine, particularly a folding press comprising at least one manipulator for seizing and moving metal sheet parts with a gripper head fitted with gripping means; an electronic controlling device for controlling the movements of the manipulator; as well as a measuring system for determining the position of the metal sheet parts. The measuring system is formed by an optoelectronic measuring device, particularly an image acquisition means, and a transillumination platform.

Abstract: A calibration system includes a tube or other conduit, a gas source, and a computational device. The tube has an end positioned relative to a flow sensor, and is in communication with the gas source. The tube and gas source introduce calibration gas into the tube at a repeatable mass flow. During a calibration operation, the conduit directs at least a portion of the calibration gas onto the flow sensor. The computational device is used to calculate an estimated flow rate of the calibration gas based upon the measurements obtained from the flow sensor.

Abstract: A gas concentration measurement instrument comprises: ultrasonic wave transmitting means for transmitting an ultrasonic wave according to an ultrasonic wave generation signal composed of a group of rectangular pulse waves; ultrasonic wave receiving means for converting the ultrasonic wave transmitted through the gas in the measurement region into an electric signal to use it as an ultrasonic wave reception signal; and gas concentration measuring means for measuring the signal output time when the ultrasonic wave generation signal is outputted, generating an envelope processing signal by subjecting the ultrasonic wave reception signal to an envelope extracting processing, measuring the threshold fall time when the envelope processing signal decreases below a predetermined threshold after exceeding the threshold, and measuring the difference between the threshold fall time and the signal output time as change in the gas concentration.

Abstract: A chemical sensing system has: an interrogation unit operable to wirelessly transmit an interrogation signal and wirelessly receive a response; an environmentally sealed container for holding a chemical analyte; a sensor array unit in fluid communication with the analyte disposed within the container, where the sensor array unit is operable to generate a response in the presence of a chemical stimulus; and a passive responder unit connected with the sensor array unit, the responder unit being powered from the interrogation signal, where the responder unit is operable to wirelessly receive the interrogation signal and wirelessly transmit the response to the interrogation signal to the interrogation unit.

Abstract: A residual life indicating system for a filter includes a main filter, a sampling filter, and a sensor. Both the main filter and the sampling filter receive an ambient gas meant to be filtered. The sensor connects to the sampling filter and senses the presence of a predetermined chemical in the gas that has been filtered by the sampling filter.

Abstract: A mail tub in the form of a substantially rigid container and a removable lid which seals the container. The container includes an air inlet port and an air outlet port for sampling air in the mail tub for possible biological contamination, such as anthrax. The container includes structure along the bottom and walls to prevent mail from contacting the walls and bottom. Such structure, in one embodiment, may include raised standoffs along the bottom of the container and channels along the walls to facilitate airflow efficiency through the mail tub when the lid is attached and an air pressure source is applied to the one of the ports. Air samples of the sealed container air are collected for contamination analysis.

Abstract: A knock sensor is constructed by putting and fitting components including an annular piezoelectric element, terminal plate, insulating sheet and weight onto a base consisting of a flange portion and a tubular portion, forming a groove part on a tip outer circumferential surface of the tubular portion, fitting a stopper ring functioning to apply an axial preload to the components onto the tubular portion, and caulking fixedly the stopper ring and the tubular portion into the groove part.

Abstract: A filter system having in-situ scan capabilities is provided. In one embodiment of the invention, the system includes a downstream probe which may be rotated to scan the field of a filter installed in the system. The probe may be utilized for leak detection, velocity measurements, efficiency testing and the like. In one embodiment, one or more probes are rotated downstream of the filter to scan the downstream face of the filter.

Abstract: A rheometer comprises a vessel mounted on a stand and a rotatable blade mounted above the vessel. A substance for rheometric assessment is put in the vessel. The rotor is advanced linearly into the substance while at the same time rotating. The blade is arranged with a profile such that there is substantially zero slip as it progresses, thereby minimising disturbance to the substance. The rheometric assessment is based on the axial force exerted as a result of the resistance of the substance to the progression of the blade through it.

Abstract: A piezoelectric resonator is immersed in a liquid, an AC signal is applied, and a local maximum of the conductance is determined. A frequency change due to the viscosity effect is determined from two frequencies of three frequencies including a resonance frequency that is applied at that local maximum, and first and second half-value frequencies at which a half-value conductance of half that local maximum is given. The influence of the mass effect can be eliminated, so that an accurate measurement of the viscosity change is possible. Moreover, if the substance to be analyzed that is contained in the liquid adheres to a reaction film of the piezoelectric resonator, the mass of the piezoelectric resonator changes, and the second half-value frequency is measured. It is thus possible to derive only the influence of the mass effect, since the half-value frequencies are not influenced by the viscosity effect.