WO3 nano-ribbons: their phase transformation from tungstite (WO3·H2O) to tungsten oxide (WO3)

Tungsten oxide (WO₃) nano-ribbons (NRs) were obtained by annealing tungstite (WO₃·H₂O) NRs. The latter was synthesized below room temperature using a simple, environmentally benign, and low cost aging treatment of precursors made by adding hydrochloric acid to diluted sodium tungstate solutions (Na₂WO₄·2H₂O). WO₃ generates significant interests and is being used in a growing variety of applications. It is therefore important to identify suitable methods of production and better understand its properties. The phase transformation was observed to be initiated between 200 and 300 ^°C, and the crystallographic structure of the NRs changed from orthorhombic WO₃·H₂O to monoclinic WO₃. It was rigorously studied by annealing a series of samples ex situ in ambient air up to 800 ^°C and characterizing them afterward. A temperature-dependent Raman spectroscopy study was performed on tungstite NRs between minus 180 and 700 ^°C. Also, in situ heating experiments in the transmission electron microscope allowed for the direct observation of the phase transformation. Powder X-ray diffraction, electron diffraction, electron energy-loss spectroscopy, and X-ray photoelectron spectroscopy were employed to characterize precisely this transformation.     

Calibration and testing of a TLD dosemeter for area monitoring

The response of a TLD-600/TLD-700 area dosemeter has been characterized in neutron fields around the 590 MeV cyclotron ring at the Paul Scherrer Institute (PSI). The dosemeter is based on a cylindrical paraffin moderator with three of each type of TLD chip at the centre, and is intended to use for area monitoring around accelerator facilities. The dosemeter is calibrated in terms of ambient dose equivalent using a non-moderated 252Cf neutron source. The ambient dose equivalent response has been tested in five locations where the neutron fields and dose rates have been well characterized by Bonner sphere spectrometer and active neutron monitor measurements. The different spectrum shapes and dose rates in the five locations permit the comparison of the behavior of the active and passive dosemeters in these neutron fields.     

A computational tool based on voxel geometry for dose reconstruction of a radiological accident due to external exposure

In the case of overexposure to ionising radiation, estimation of the absorbed dose in the organism is an important indicator for evaluating the biological consequences of this exposure. The physical dosimetry approach is based either on real reconstruction of the accident, using physical phantoms, or on calculation techniques. Tools using Monte Carlo simulations associated with geometric models are very powerful since they offer the possibility to simulate faithfully the victim and the environment for dose calculations in various accidental situations. Their work presents a new computational tool, called SESAME, dedicated to dose reconstruction of radiological accidents based on anthropomorphic voxel phantoms built from real medical images of the victim in association with the MCNP Monte Carlo code. The utility was, as a first step, validated for neutrons by experimental means using a physical tissue-equivalent phantom.     

Exposure of aircraft crew to cosmic radiation: on-board intercomparison of various dosemeters

Owing to their professional activity, flight crews may receive a dose of some millisieverts within a year; airline passengers may also be concerned. The effective dose is to be estimated using various experimental and calculation tools. The European project DOSMAX (Dosimetry of Aircrew Exposure during Solar Maximum) was initiated in 2000 extending to 2004 to complete studies over the current solar cycle during the solar maximum phase. To compare various dosemeters in real conditions simultaneously in the same radiation field, an intercomparison was organised aboard a Paris-Tokyo round-trip flight. Both passive and active detectors were used. Good agreement was observed for instruments determining the different components of the radiation field; the mean ambient dose equivalent for the round trip was 129 +/- 10 microSv. The agreement of values obtained for the total dose obtained by measurements and by calculations is very satisfying.     

Micromixers to produce cosmetic emulsions

In the cosmetics industry, emulsions play a key-role in active solubilization and texture/efficacy optimization. However, depending on their physico-chemical properties, the active ingredients are often more stable in a single phase: for example, Vitamin A is more stable in an oily phase than in a water phase. We have developed a special mixing device which produces an emulsion in the body of the pump, immediately before application on the skin. The mixing unit consists of two silicon chips. Each chip has several Y-shaped microchannels and intersections etched on its upper surface. When the two etched surfaces are bonded together, they produce series of interconnecting micromixing elements which permit the repeat mixing of the two phases, thus producing an extremely homogenous emulsion. These micromixers require carefully designed formulae in which the physico-chemical properties of each raw material are essential to obtain a spontaneous emulsion. This device has been incorporated into a spray pack and optimized to deliver the spontaneous emulsion when finger pressure is applied.     

Consumer perceptions: pork and pig production. Insights from France, England, Sweden and Denmark

Consumer focus groups in France, England, Sweden and Denmark were used to obtain insights into the decision-making involved in the choice of fresh pork and attitudes towards today's pig production systems. Many positive perceptions of pork meat were evoked. Negative images of the production systems in use today were expressed, but rationalised in terms of consumer demands, market competition and by comparisons to previous systems of production. Knowledge of production systems appeared of little consequence in terms of any meat market potential as several groups freely remarked that there was no link between the negative images of production methods and their purchase behaviour. The groups were clearly confused and mistrusted the limited information available at the point of purchase. Careful consideration should be given to meat labelling, in particular taking account of the evident consumer ethnocentrism, to assure that such information is targeted to enhance consumer confidence.     

Relationship between Sensory and Instrumental Hardness of Commercial Cheeses

ABSTRACT: The effect of deformation (10% to 90%) and deformation rate (0.2 to 10 mm/s) on both maximum compression force and correlation between sensory and instrumental measurements of hardness were investigated for 26 commercial cheeses. Log-linear regression models were used to model the relationship between deformation rate and maximum compression force and fitted well to the relationship, indicating that maximum compression force is a log linear function of deformation rate. Deformation had a large effect on the correlation between sensory and instrumental hardness, while deformation rate had a small effect. The optimal deformation and deformation rate for the maximum correlation were 70% to 90% and 1.0 mm/s, respectively. This implies that an optimal combination of deformation and deformation rate can be used for maximizing the correlation between sensory and instrumental hardness for cheese products.