To date, thermistors are used to continuously monitor the body temperature of newborn babies in the neonatal intensive care unit. The thermistor probe is attached to the body with a strong adhesive tape to ensure that the probe stays in place. However, these strong adhesives are shown to increase microbial growth and cause serious skin injuries via epidermal stripping. The latter compromises the skin's ability to serve as a protective barrier leading to increase in water loss and further microbial infections. In this paper, a new approach is introduced that eliminates the need for an adhesive. Instead, two kinds of fluorophores are entrapped in a skin-friendly chitosan gel that can be easily wiped on and off of the skin, and has antimicrobial properties as well. A CCD camera is used to detect the temperature-dependent fluorescence of the fluorophore, tris(1,10-phenthroline)ruthenium(II) while 8-aminopyrene-1,3,6-trisulfonic acid serves as the reference. This temperature sensor wa...

A new algorithm for tip radius correction for the metrology of free-form and two-dimensional contours is proposed. The method is for use in a high-definition coordinate metrology context, as is now possible with scanning probes, where the density of points per scanned distance ensures that the successive probe ball positions overlap partially with each other. The proposed method for correcting measurements can be applied directly to the data collected during a coordinate measuring machine (CMM) measuring process. An additional advantage of the new algorithm is the possibility of detecting the incoherent corrected measured point, a form of validity check. The algorithm performance was verified experimentally on a Zeiss ACCURA CMM with an active VAST Gold scanning probe.

In large scale coordinate metrology, estimates of target coordinates are determined from range and angle observations gathered by one or more laser trackers. In analysing such data, it is required to weight the range observations relative to the angle observations. While the system characterization will give a guide to the accuracy of these measurements, the actual behaviour will depend strongly on environmental effects, particularly those influencing the refractive index of the air. In this paper, we describe a general Bayesian approach to balancing sets of observational data in which the noise parameters are treated as unknowns but associated with prior distributions. Estimates of the appropriate weighting factors are derived from the posterior distributions for these noise parameters. We give examples of this general approach applied to the analysis of laser tracker data.

This work presents a novel method for replacing erroneous measurements in digital particle image velocimetry (DPIV) data using an adaptive reconstruction with gappy proper orthogonal decomposition (POD). Previous studies have shown that gappy POD can be used to replace erroneous data with high accuracy. Conventional gappy POD methods employ a spatially constant number of modes for reconstructing the missing information across the entire field. In contrast, the method presented herein proposes a locally adaptive criterion that allows for determination of the optimum number of POD modes required for the reconstruction of each replaced measurement. This reconstruction produces higher accuracy results using more POD modes than with previous POD methods. The new method was compared against commonly utilized techniques for DPIV vector replacement, namely Kriging, bootstrapping and basic interpolation, as well as previously presented POD reconstruction techniques. The results showed tha...

The flow field inside rotating test sections can be investigated by means of particle image velocimetry (PIV) operated in the phase-locked mode. With this experimental approach, the measurement system is kept fixed and it is synchronized with the periodical passage of the test section. Therefore, the direct output of the PIV measurements is the absolute velocity field, while the relative one is indirectly obtained from proper data processing that relies on accurate knowledge of the peripheral velocity field. This work provides an uncertainty analysis about the evaluation of the peripheral displacement field in phase-locked PIV measurements. The analysis leads to the detection of the levels of accuracy required in the estimation of both the angular velocity and the position of the center of rotation to ensure correct evaluation of the peripheral displacement field. In this regard, a simple methodology is proposed to evaluate the center of rotation position with an accuracy below 1...

Cystic fibrosis (CF) is a life-threatening genetic disease. At present, the common method for diagnosis of CF is to detect the chloride concentration in sweat using ion-selective electrodes. However, the current sweat testing methods require a relatively large quantity of sweat sample, at least 25 µL, which is very difficult to obtain, especially for newborns. This paper presents a new method and a new device for rapid detection of the chloride concentration from a small volume of solution. In this method, the chloride concentration is determined quantitatively by the fluorescence intensity of MQAE, a chloride ion fluorescent indicator. In this device, the sample is carried by a small piece of filter paper on a cover glass exposed to an UV LED light source. The resulting fluorescent signals are detected by a Si photodiode. Data acquisition and processing are accomplished by LabVIEW software in a PDA. Based on the Stern–Volmer relationship, the effects of different parameters on t...

Measurement of the in situ dc magnetic field on space science missions is most commonly achieved using instruments based on fluxgate sensors. Fluxgates are robust, reliable and have considerable space heritage; however, their mass and volume are not optimized for deployment on nano or picosats. We describe a new magnetometer design demonstrating science measurement capability featuring significantly lower mass, volume and to a lesser extent power than a typical fluxgate. The instrument employs a sensor based on anisotropic magnetoresistance (AMR) achieving a noise floor of less than 50 pT Hz ^−1/2 above 1 Hz on a 5 V bridge bias. The instrument range is scalable up to ±50 000 nT and the three-axis sensor mass and volume are less than 10 g and 10 cm ³, respectively. The ability to switch the polarization of the sensor's easy axis and apply magnetic feedback is used to build a driven first harmonic closed loop system featuring improved linearity, gain stab...

Making use of a newly available rapid-tuning diode laser operating at wavelengths up to 2.9 µm, an absorption-based temperature sensor was developed for in situ measurements in low-pressure flames. Based on the systematic analysis of H ₂O vapor transitions in the fundamental vibrational bands (ν ₁ and ν ₃) of H ₂O in the range of 2.5–3.0 µm, an optimal closely-spaced spectral line pair near 2.9 µm was selected for its temperature sensitivity in the range of 1000–2500 K. The narrow-linewidth room-temperature laser was scanned repetitively across these spectral features at 5 kHz, enabling fast, accurate temperature sensing. Use of the temperature sensor was investigated in low-pressure flames supported on a McKenna burner at 15, 25 and 60 Torr. To avoid absorption by the cold gases in the flame edges and the recirculation region between the burner and the vacuum chamber wall, a variable-path in situ probe was designed and an opt...

The movement of the circular piston in an oscillating piston positive displacement flowmeter is important in understanding the operation of the flowmeter, and the leakage of liquid past the piston plays a key role in the performance of the meter. The clearances between the piston and the chamber are small, typically less than 60 µm. In order to measure this film thickness a fluorescent dye was added to the water passing through the meter, which was illuminated with UV light. Visible light images were captured with a digital camera and analysed to give a measure of the film thickness with an uncertainty of less than 7%. It is known that this method lacks precision unless careful calibration is undertaken. Methods to achieve this are discussed in the paper. The grey level values for a range of film thicknesses were calibrated in situ with six dye concentrations to select the most appropriate one for the range of liquid film thickness. Data obtained for the oscillating piston...

A general design of a laser light sheet module with adjustable focus is presented, where the maximum sheet width is preserved over a fixed region. In contrast, conventional focusing designs are associated with a variation in maximum sheet width with focal position. A four lens design is proposed here, where the first three lenses are employed for focusing, and the last for sheet expansion. A maximum sheet width of 1100 µm was maintained over a 50 mm long distance, for focal distances ranging from 75 to 500 mm, when a 532 nm laser beam with a beam quality factor M ² = 29 was used for illumination.