A method for determining the prestress force of a connection component (10) is proposed. In the method, ultrasonic signals (22) are introduced into the connection component (10) and ultrasonic echoes (24) of the ultrasonic signals (22) are received again. The method comprises the following steps: a) introducing a longitudinal ultrasonic signal and determining a first signal time of flight FTOF.sub.L of the longitudinal ultrasonic signal until the reception of an echo of the longitudinal ultrasonic signal, b) introducing a transverse ultrasonic signal and determining a second signal time of flight FTOF.sub.T of the transverse ultrasonic signal until the reception of an echo of the transverse ultrasonic signal, and c) determining an effective temperature T.sub.eff and the prestress force of the connection component (10) on the basis of the first signal time of flight FTOF.sub.L, the second signal time of flight FTOF.sub.T, previously determined reference data and calibration factors using the assumption that a prestress force F.sub.L ascertained using the first signal time of flight FTOF.sub.L and a prestress force F.sub.T ascertained using the second signal time of flight FTOF.sub.T are equal in magnitude,
wherein steps a) and b) are carried out successively in any desired order or in parallel. A further aspect of the invention relates to a device for carrying out the method.

A system for determining one or more properties of one or more gases. The system comprises sensors configured to measure thermal conductivity and exothermic responses of a sample at multiple temperatures. Sensor responses to exposure to a gas sample at two or more temperatures are compensated and analyzed by a subsystem. The subsystem is configured to determine a thermal conductivity of the gas sample at each of the two or more temperatures and determine at least one component of the gas sample based at least in part on the thermal conductivity value of the sample at each of the two or more temperatures. Related systems and methods of determining one or more properties of a sample are also disclosed.

The invention comprises a device and method to estimate the elasticity of soft elastic solids from surface wave measurements. The method is non-destructive, reliable and repeatable. The final device is low-cost and portable. It is based in audio-frequency shear wave propagation in elastic soft solids. Within this frequency range, shear wavelength is centimeter sized. Thus, the experimental data is usually collected in the near-field of the source. Therefore, an inversion algorithm taking into account near-field effects was developed for use with the device. Example applications are shown in beef samples, tissue mimicking materials and in vivo skeletal muscle of healthy volunteers.

A system for detecting characteristics of a fluid includes a sonic sensor. The sonic sensor includes a transducer, a transduction surface, and an acoustically reflective pad member. The transducer may be contained within a probe body, and the transduction surface may be an element of the probe body. A stem may connect the pad member to the transduction surface. The transducer will generate pulses that are transmitted to the pad member via a fluid when the transduction surface and pad member are immersed in the fluid. The system will detect the pulses when reflected and use that data to determine a speed of sound within the fluid. The system may use the speed of sound to determine density, specific gravity and/or stiffness of the fluid. The system may use that determination to assess a level of processing activity of the fluid, such as fermentation activity.

A device for determining and/or monitoring a process variable of a medium includes a sensor unit having a mechanically oscillatable unit, a first piezoelectric element, a unit for determining and/or monitoring a temperature of the medium and an electronic system. The device is designed to excite the mechanically oscillatable unit and to receive the mechanical oscillations of the oscillatable unit, to convert them into a first receiving signal, to emit a transmission signal and to receive a second receiving signal, wherein the electronic system is designed to determine the process variable based on the first and/or second receiving signal. The unit for determining and/or monitoring the temperature includes a first and a second temperature sensor arranged at a distance from one another, and the electronic system is designed to determine the temperature of the medium based on a first and/or second temperature receiving signal.

A system for measuring fluid flow in a wellbore is provided. A probe includes at least a heater. A fiber optic cable is connected to the probe. The system is programmed to perform operations including: changing an output of the heater to thereby change a temperature of drilling fluid moving over a fiber optic cable; measuring a strain on the fiber optic cable caused by changing the temperature of the drilling fluid; preliminarily determining a velocity of the drilling fluid from the measured strain; measuring at least a second parameter of the drilling fluid; adjusting the preliminary determined velocity based on the measured at least a second parameter to yield an adjusted velocity; and determining a flow rate of the drilling fluid based on the adjusted velocity.

A concentration measuring instrument includes a piezoelectric vibrator transmitting an ultrasonic wave into a solution contained in a cavity and detecting the ultrasonic wave reflected, a temperature sensor measuring a temperature of the solution, a drive circuit generating a drive signal driving the piezoelectric vibrator, a phase comparator performing a phase comparison between the drive signal and a detection signal, a frequency setting circuit making the drive circuit generate drive signals having sequentially different frequencies and monitoring a phase comparison result to detect a resonant frequency, and a Phase Locked Loop (PLL) circuit making a frequency of the drive signal follow the detected resonant frequency. A microcomputer determines a concentration of a solute in the solution on a basis of the frequency of the drive signal while the PLL circuit is being operated and a result of a temperature measurement by the temperature sensor.

A variable value calculating process includes: measuring a propagation time of the propagation of an ultrasound wave through a measurement sector inside a housing; obtaining a temperature calculated value on the basis of the measured value of the propagation time and a reference distance for the measurement sector; obtaining a temperature measured value by measuring the temperature inside the housing; and obtaining a temperature replacement fluctuation value indicating a difference between the temperature calculated value and the temperature measured value. The variable value calculating process is executed for each of a plurality of temperature conditions under which the temperature of a reference gas inside the housing differs. A temperature compensation table in which the temperature of a gas to be measured is associated with a temperature compensation value relating to the temperature is obtained on the basis of the temperature replacement fluctuation values obtained under each temperature condition.

A system and method for detecting an anomaly in a structure using an adaptive filter to compensate for variations in piezoelectric transducer performance due to environmental factors such as temperature. A first voltage signal having a first amplitude is sent to a reference piezoelectric actuator. Thereafter, a first reference voltage signal is received from a reference piezoelectric receiver which is acoustically coupled to detect the guided wave generated by the reference piezoelectric actuator. A second amplitude is determined using an optimization algorithm of an adaptive filter to compensate for nonlinear behavior of the reference piezoelectric actuator and receiver based on the first reference voltage signal. Then the adaptive filter sends a second voltage signal having the second amplitude to the reference and test piezoelectric actuators. Reference and test voltage signals are received from the reference and test piezoelectric receivers in response to the second voltage signal. A difference voltage signal representing differences between the reference and test voltage signals received is then recorded.

A transducer system. The system comprises a transducer and circuitry for applying an excitation waveform to excite the transducer during an excitation period. The circuitry for applying has: (i) circuitry for applying a first waveform at a first frequency; and (ii) circuitry for applying a second waveform at a second frequency differing from the first frequency.