An optical detection scheme for on-chip, high sensitivity refractive index detection is based on micro-interferometry, and allows for picoliter detection volumes and universal analyte sensitivity. The invention employs three main elements: a source (12) of coherent light, such as a VCSEL, laser diode or He-Ne laser; an etched channel (22) of capillary dimensions in a substrate (20) for reception of a sample to be analyzed; and a photodetector (25) for detecting laser light reflected off of the channel (22). The laser source (12) generates an unfocused laser beam (14) that is incident on the etched channel (22). A unique multi-pass optical configuration is inherently created by the channel characteristics, and is based on the interaction of the unfocused laser beam (14) and the curved surface of the channel (22), that allows RI measurments in small volumes at high sensitivity. The entire device, including the laser source (12) and the photodetector (25) can be formed on a single microchip. The detector has numerous applications, including universal/RI detection for CE (capillary electrophoresis), CEC (capillary electrochromatography) and FIA, physiometry, cell sorting/detection by scatter, ultra micro calorimetry, flow rate sensing and temperature sensing.

Interferometric detection system and method

A low power apparatus for measuring various process parameters and/or physical properties of a fluid or gas medium by measuring the change of a wave signal or time dependent signal as it traverses the fluid or gas medium, the apparatus comprising: at least one transmission transducer for providing a transmitted wave or time dependent signal for injection into the fluid or gas medium; at least one reception transducer, displaced from the transmission transducer for receiving a received wave or time dependent signal from the fluid or gas medium; and an analog signal processor, coupled to the reception transducer, for processing of the received wave or time dependent signal such that a short interval of the processed received wave or time dependent signal is extracted.

Low power signal processing and measurement apparatus

A contactless, electromagnetic (EM) replacement (substitute, alternative) for cabled (electric) Standards-based interfaces (such as, but not limited to USB) which effectively handles the data transfer requirements (such as bandwidth, speed, latency) associated with the Standard, and which is also capable of measuring and replicating relevant physical conditions (such as voltage levels) on data lines so as to function compatibly and transparently with the Standard. A contactless link may be provided between devices having transceivers. A non-conducting housing may enclose the devices. Some applications for the contactless (EM) interface are disclosed. A dielectric coupler facilitating communication between communications chips which are several meters apart. Conductive paths may provide power and ground for bus-powered devices.

Contactless replacement for cabled standards-based interfaces

A method for determining the flow rates of a fluid comprising a multi-component mixture of a gas and at least one liquid in a pipe, the method comprising the following steps: a) the multi-component mixture flow is conditioned to create a symmetrical annular gas concentration flow condition, b) the density distribution and/or dielectric constant distribution in said symmetrical flow within a cross-section of the pipe is determined, c) a function describing the radial distribution of density and/or radial distribution of dielectric constant is determined, d) the velocity of the multi-component mixture is determined, e) the temperature and pressure are obtained, and, f) based on the knowledge of densities and/or dielectric constants of the components of the fluid mixture, and the result from the above steps a-e, the volume and/or mass flow rates of the gas and liquid components of the fluid mixture are calculated. An apparatus for performing the method is also disclosed.

A method and apparatus for tomographic multiphase flow measurements

A high frequency oscillatory ventilator for infants and adults using feedback control to maintain either the desired tidal volume or pressure delivered to the subject. The inspiratory to expiratory time ratio of the ventilator is variable. The ventilator corrects the measured pressure for arbitrarily-sized endotracheal tubes and calculates the actual pressure or tidal volume delivered to the subject. The ventilator also separates the source of the tidal volume oscillations from the patient circuit with a flexible membrane or diaphragm, allowing transmission of oscillating tidal volumes while blocking mean airway pressures. The patient circuit is flexible, but fabricated from low-compliance material to minimize the loss of tidal volume. The ventilator uses feedback control of the exhaust flow to maintain mean airway pressure in the presence of an independently controlled bias flow. Further, a respiratory impedance measurement system is built into or connected to the patient circuit which monitors changes in lung mechanics while the patient is connected to the high frequency ventilator without changing mean airway pressure or removing the patient from the ventilator.

High frequency oscillatory ventilator and respiratory measurement system

The arrangement for contactless measurement of the volume flow or mass flow of a moving medium comprises two transducers which furnish electrical signals into which inhomogeneities of the moving medium enter depending on their spatial position in accordance with different spatial weighting functions. The detecting regions of the two transducers are offset with respect to each other in the direction of movement of the medium but partially overlap in such a manner that the gradient of the spatial cross correlation function for the spatial displacement zero is different from the zero vector. A correlator forms the time cross correlation function of the two signals and an evaluation circuit derives the measured value for the volume flow or mass flow of the moving medium from the gradient of the time cross correlation function for the time displacement zero. Alternatively, the measured value may also be derived from the first moment of the cross power density spectrum of the two signals because said moment is mathematically equivalent to the gradient of the time cross correlation function of the two signals for the time displacement zero.

Arrangement for contactless measurement of the volume flow or mass flow of a moving medium

Compared to chemical reactors, there are additional requirements to be considered when selecting and designing a bioreactor. The cultivated organisms and most of the desired products are to a greater or lesser extent sensitive to temperature, pH and Shear stress. Furthermore, sterilization often plays an important role in maintaining a monoseptic process. Many design procedures for chemical reactors can be applied but requirements which are relevant to the biological system are sometimes decisive. Consequently, it is useful to first consider the essential features of the organisms with respect to the selection and design of bioreactors. Attention must be paid to the fermentation medium because its flow behaviour can range from slightly viscous and Newtonian to highly viscous, non-Newtonian. Many papers deal with low viscosity fermentation broths [1–5]. However, little is known about the design of bioreactors for highly viscous non-Newtonian liquids. Fundamentals for the design of bioreactors are presented. It has been attempted to apply theoretical equations suitable for both, low viscosity Newtonian and high viscosity non-Newtonian fermentation broths. Apart from the calculation procedure for the OTR-values, the difference between global and local values within bioreactor is demonstrated by means of velocity and shear stress profiles. Special requirements for bioreactors such as prevention of excessive foaming, shear sensitivity of micro-organisms and cell-lines and effective sterilization are also discussed.

Selection and design of aerobic bioreactors

An arrangement for generating mean-value-free binary signals includes a binarizing circuit which receives an analog signal to be binarized and binarizes said signal with respect to a binarizing threshold. Connected to the output of the binarizing circuit is a closed-loop control circuit which includes a differential integrator which receives at the one input the binary signal from the output of the binarizing circuit. Applied to the second input of the differential integrator is a desired value signal which corresponds to the mean value between the two signal levels of the binary signal. The differential integrator integrates the deviation between the binary signal and the desired value signal and furnishes a signal corresponding to the integrated deviation. By the signal corresponding to the integrated deviation the position of the analog signal relatively to the binarizing threshold is shifted in a sense such that the mean value of the deviation is regulated to zero. For this purpose either the signal corresponding to the integrated deviation can be superimposed on the analog signal prior to the binarizing or the binarizing threshold can be varied by the signal corresponding to the integrated deviation. Preferably, the desired value signal is produced by integration of a mean-value-free binary signal.

Method and arrangement for generating a mean-value-free binary signal

Anordnung zur beruehrungslosen messung des volumen- oder massenstroms eines bewegten mediums

Correlation flowmeters have been used in the scientific field for many years and are actually gaining greater commercial importance due to an increasing number of applications in industrial plants. The importance of the correlation method is based on the fact that essentially no alternatives exist for measuring velocity and mass flow rate in pneumatic conveyors. However, the hitherto employed transit time correlation method leads to results which are clouded by uncertainties. The commonly used theoretical model of the measurement process does not explain these effects satisfactorily. Therefore, the theory of non-intrusive flow sensors is reinvestigated from a physical standpoint. The derived model permits a discussion of the transit time correlation method in some detail. Furthermore, this model leads to an alternative sensor arrangement and signal processing scheme which makes it possible to measure the true mean velocities. Examples of experimental results are given.

Georg Schneider

Papers

Arrangement for contactless measurement of the volume flow or mass flow of a moving medium

Selection and design of aerobic bioreactors

Method and arrangement for generating a mean-value-free binary signal

Anordnung zur beruehrungslosen messung des volumen- oder massenstroms eines bewegten mediums

Theory and application of an alternative correlation flowmeter