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21.
David-A. Mendels Emmelyn M. Graham Steven W. Magennis Anita C. Jones François Mendels 《Microfluidics and nanofluidics》2008,5(5):603-617
The development and adoption of lab-on-a-chip and micro-TAS (total analysis system) techniques requires not only the solving
of design and manufacturing issues, but also the introduction of reliable and quantitative methods of analysis. In this work,
two complementary tools are applied to the study of thermal and solutal transport in liquids. The experimental determination
of the concentration of water in a water–methanol mixture and of the temperature of water in a microfluidic T-mixer are achieved
by means of fluorescence lifetime imaging microscopy (FLIM). The results are compared to those of finite volume simulations
based on tabulated properties and well-established correlations for the fluid properties. The good correlation between experimental
and modelled results demonstrate without ambiguity that (1) the T-mixer is an adiabatic system within the conditions, fluids
and flow rates used in this study, (2) buoyancy effects influence the mixing of liquids of different densities at moderate
flow rates (Reynolds number Re ≪ 10−2), and (3) the combination of FLIM and computational fluid dynamics has the potential to be used to measure the thermal and
solutal diffusion coefficients of fluids for a range of temperatures and concentrations in one single experiment. As such,
it represents a first step towards the full-field monitoring of both the extent and the kinetics of a chemical reaction.
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David-A. MendelsEmail: |
22.
Christian Bur Peter Reimann Mike Andersson Anita Lloyd Spetz Andreas Schütze 《Microsystem Technologies》2012,18(7-8):1015-1025
A silicon carbide based enhancement type metal insulator field effect transistor with porous gate metallization has been investigated as a total NO x sensor operated in a temperature cycling mode. This operating mode is quite new for gas sensors based on the field effect but promising results have been reported earlier. Based on static investigations we have developed a suitable T-cycle optimized for NO x detection and quantification in a mixture of typical exhaust gases (CO, C2H4, and NH3). Significant features describing the shape of the sensor response have been extracted and evaluated with multivariate statistics (e.g. linear discriminant analysis) allowing quantification of NO x . Additional cleaning-cycles every 30?min improve the stability of the sensor further. With this kind of advanced signal processing the influence of sensor drift and cross sensitivity to ambient gases can be reduced effectively. Measurements have proven that different concentrations of NO x can be detected even in a changing mixture of other typical exhaust gases under dry and humid conditions. In addition to that, unknown concentrations of NO x can be detected based on a small set of training data. It can be concluded that the performance of GasFETs for NO x determination can be enhanced considerably with temperature cycling and appropriate signal processing. 相似文献
23.
Housing privatisation is commonly understood in political economic terms. The proponents of privatisation argue that the provision of ownership enables households to have security of tenure, which in turn leads to increased housing investment, the development of a secondary housing market and a source of income for the local authority by means of land tax. On the other hand, critics of housing privatisation suggest that such processes lead to landlordism and an increased dependence on mortgage finance. This paper uses historical methodology to trace the historical lack of secure tenure for urban black South Africans. The data consists of 395 structured questionnaires conducted in the case study area of Mangaung, the former black township of Bloemfontein. The results suggest that housing privatisation processes in South Africa cannot be viewed only through a political economic lens. 相似文献
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Violeta Ivanova Marina Stefova Trajče Stafilov Borimir Vojnoski Ildiko Bíró Anita Bufa Ferenc Kilár 《Food Analytical Methods》2012,5(6):1427-1434
An analytical method for determination of volatile composition of wines using sample preparation by liquid–liquid extraction and gas chromatography coupled to mass spectrometry for separation and detection has been developed and validated. Extraction of volatile compounds was performed in dichloromethane, and 1-octanol was added as an internal standard. Kékfrankos red wine produced in Villány wine region in Hungary was used as a model wine for testing and validation of the method. The developed method allowed satisfactory determination of 33 volatile compounds in the wines. Compounds analyzed include alcohols, esters, lactones, fatty acids, furans, and nitrogen compounds. The calibration curves of the four reference compounds used (2-phenyl ethanol, ethyl nonanoate, butyrolactone, and tyrosol) were linear in all cases with correlation coefficients (R 2) ranging from 0.9951 to 0.9992. The accuracy of the method was checked with a standard addition method (recovery 92.2–103 %), showing good repeatability and reproducibility (RSD?<?10 %). 相似文献
26.
Urszula Krupa-Kozak Natalia Drabińska Cristina M. Rosell Costantino Fadda Andrzej Anders Tomasz Jeliński Anita Ostaszyk 《International Journal of Food Science & Technology》2019,54(4):1121-1129
Broccoli by-products, in particular leaves, are rich sources of nutritional and bioactive components thus could constitute a valuable food additive. Although an upsurge in quantity of gluten-free products is observed further studies are required on improvement of their nutritional quality and palatability. This study aimed to investigate the influence of broccoli leaf powder (BLP) on dough behaviour, and technological characteristics and sensory quality of gluten-free mini sponge cake (GFS). Broccoli leaf powder replaced an equivalent amount (2.5%, 5%, 7.5%; w/w) of corn and potato starches in GFS formulation. Applied BLP increased the instrumental firmness of GFS but sensorial attributes (elasticity, crustiness, mastication and adhesiveness) were similar to the control. All broccoli GFS were vividly green, had small size pores properly distributed. Among them, sample with 2.5% BLP was distinguished for its desirable sensory quality, despite a slightly perceived cabbage aroma and taste. Moderate amount of BLP allows to preserve a good quality GFS improving its attractiveness and palatability. 相似文献
27.
Martti Heinonen Miltiadis Anagnostou Stephanie Bell Mark Stevens Robert Benyon Reidun Anita Bergerud Jovan Bojkovski Rien Bosma Jan Nielsen Norbert B?se Plunkett Cromwell Aliye Kartal Dogan Seda Aytekin Ali Uytun Vito Fernicola Krzysztof Flakiewicz Bertrand Blanquart Domen Hudoklin Per Jacobson Anders Kentved Isabel Lóio George Mamontov Alexandra Masarykova Helmut Mitter Regina Mnguni Jan Otych Anton Steiner Nagyné Szilágyi Zsófia Davor Zvizdic 《International Journal of Thermophysics》2012,33(8-9):1422-1437
In the field of humidity quantities, the first CIPM key comparison, CCT-K6 is at its end. The corresponding European regional key comparison, EUROMET.T-K6, was completed in early 2008, about 4?years after the starting initial measurements in the project. In total, 24 NMIs from different countries took part in the comparison. This number includes 22 EURAMET countries, and Russia and South Africa. The comparison covered the dew-point temperature range from ?50?°C to +20?°C. It was carried out in three parallel loops, each with two chilled mirror hygrometers as transfer standards in each loop. The comparison scheme was designed to ensure high quality results with evenly spread workload for the participants. It is shown that the standard uncertainty due to the long-term instability was smaller than 0.008?°C in all loops. The standard uncertainties due to links between the loops were found to be smaller than 0.025?°C at ?50?°C and 0.010?°C elsewhere. Conclusions on the equivalence of the dew-point temperature standards are drawn on the basis of calculated bilateral degrees of equivalence and deviations from the EURAMET comparison reference values (ERV). Taking into account 16 different primary dew-point realizations and 8 secondary realizations, the results demonstrate the equivalence of a large number of laboratories at an uncertainty level that is better than achieved in other multilateral comparisons so far in the humidity field. 相似文献
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29.
A few studies suggest that drivers with Parkinson's disease (PD) may self-regulate or modify their driving behavior more than drivers without neurological disorders; however findings are limited to self-report. The purpose of this study was to objectively examine whether drivers with PD show more restrictive driving practices (exposure and patterns). Electronic devices were installed in the vehicles of 27 drivers with PD (71.6 ± 6.6; 78% men) and 20 matched controls (70.6 ± 7.9; 80% men) for two weeks and driving data were matched with aerial maps, weather and daylight archives and trip logs to examine driving context. Compared to controls, the PD group drove significantly less overall (number of trips, kilometres, duration), and proportionately less at night and on days with bad weather suggesting more restricted driving practices, congruent with lower ratings of driving comfort and abilities. However, they may not necessarily drive more cautiously or safely as they drove significantly faster (and over the speed limit) on highways and freeways and 19% reported driving problems over the two weeks. These preliminary findings need to be replicated and longitudinal studies using objective indicators are needed to examine changes in driving practices, as well as crash outcomes, as disease severity progresses. 相似文献
30.
Anita Valmarska Dragana Miljkovic Nada Lavrač Marko Robnik-Šikonja 《Journal of Intelligent Information Systems》2018,51(2):301-337
Parkinson’s disease is a neurodegenerative disorder that affects people worldwide. Careful management of patient’s condition is crucial to ensure the patient’s independence and quality of life. This is achieved by personalized treatment based on individual patient’s symptoms and medical history. The aim of this study is to determine patient groups with similar disease progression patterns coupled with patterns of medications change that lead to the improvement or decline of patients’ quality of life symptoms. To this end, this paper proposes a new methodology for clustering of short time series of patients’ symptoms and prescribed medications data, and time sequence data analysis using skip-grams to monitor disease progression. The results demonstrate that motor and autonomic symptoms are the most informative for evaluating the quality of life of Parkinson’s disease patients. We show that Parkinson’s disease patients can be divided into clusters ordered in accordance with the severity of their symptoms. By following the evolution of symptoms for each patient separately, we were able to determine patterns of medications change which can lead to the improvement or worsening of the patients’ quality of life. 相似文献