Heinonen E.,University of Oulu |
Juuti J.,University of Oulu |
Palosaari J.,University of Oulu |
Tyholdt F.,Sintef |
And 10 more authors.
Journal of Electroceramics | Year: 2011
Piezoelectric thin film ultrasonic transducers were realised and tested for short range distance measurements. Displacements in air and water as a function of frequency were modelled by Comsol Multiphysics finite element modelling (FEM) and transducer configurations with a two electrode layout were manufactured to enable larger displacements than with the conventional design. The transducer was fabricated on a silicon wafer by chemical solution deposition (CSD) with total PZT (Pb(Zr0.53Ti0.47)O3) thickness of 2 μm. Subsequently, a cavity underneath the PZT was wet etched creating a bending membrane with a total thickness of ∼13 μm. The displacements of the transducers as a function of frequency were modelled and measured by fiber-optic laser vibrometer. The effective piezoelectric d 33 coefficient of 300 nm/V and 144 nm/V in air and 48 nm/V and 18 nm/V in water was obtained for 260∈×∈260 μm2 and 390∈×∈390 μm2 membranes, respectively. The accuracy of the modelled resonance frequencies both in air and water was relatively good, of ∼4-13% and ∼5-20%, respectively. © 2010 Springer Science+Business Media, LLC. Source
HOK Instrument AB | Date: 2011-10-06
A multifunctional breath analyzer includes a receptor unit for receiving a breath sample from a test subject, a sensing unit providing a signal corresponding to the concentration of at least one volatile substance within the sample, elements for providing a signal indicative of the dilution of the breath sample, and an analyzing unit/processing unit for the identification and quantification of the volatile substance of the breath sample. The signal processing unit is configured to perform at least two different calculations for the quantification, and the signal processing unit is also configured to automatically display the result of a selected calculation, the selection being based on the signal indicating dilution.
Hok Instrument Ab | Date: 2010-02-08
A method and apparatus for breath analysis from a test person who may be incapable of delivering controlled forced expiration. Breath sampling may be essentially contactless and is provided by active air intake to measuring cell (
Ljungblad J.,Hok Instrument AB |
Hok B.,Hok Instrument AB |
Ekstrom M.,Malardalen University
IEEE ISSNIP 2014 - 2014 IEEE 9th International Conference on Intelligent Sensors, Sensor Networks and Information Processing, Conference Proceedings | Year: 2014
In screening applications there is a need for improved breath alcohol analyzers. Accuracy, specificity, usability, and through-put are critical to the device performance. Objective: To characterize the critical performance of a new contactless breath alcohol analyzer. Methods: The device is characterized by measurements using artificial breath gas and human subjects. Breath sampling is performed in ambient air using carbon dioxide as a biomarker. Results: Resolution and inter-individual variation, response time, and specificity were shown to meet the requirements of industrial standards. The feasibility of contactless measurement was demonstrated. Conclusions: The new device exhibits sufficient performance in moderately diluted breath samples. Further work is underway to reach the objective of unobtrusive breath alcohol analysis. © 2014 IEEE. Source
Hok B.,Hok Instrument AB |
Pettersson H.,Autoliv |
Andersson A.K.,Hok Instrument AB |
Andersson A.K.,Malardalen University |
And 2 more authors.
IEEE Sensors Journal | Year: 2010
Alcolocks and alcohol screening devices are becoming commonplace, and their use is expected to grow rapidly with cost reduction and improved usability. A new breath analyzer prototype is demonstrated, with the prospects of eliminating the mouthpiece, reducing expiration time and volume, improving long-term stability, and reducing life cycle cost. Simultaneous CO2 measurements compensate for the sample dilution and un-saturated expiration. Infrared transmission spectroscopy is used for both the alcohol and CO 2 measurement, yet the entire system is contained within a small handheld unit. Experimental results are reported on the device sensitivity, linearity, resolution, and influence from varying measuring distance. The correlation between early and full-time sampling was established in 60 subjects. Basic concept verification was obtained, whereas resolution and selectivity still needs to be improved. Further improvements are expected by system optimization and integration. © 2009 IEEE. Source