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121 results on '"TAPPER, U."'

10. Nanocomposite packaging materials from polysaccharides and montmorillonite

Author

Vartiainen, J., Tekla Tammelin, Tuominen, M., Pere, J., Tapper, U., Nättinen, K., and Harlin, A.

Subjects
nanoclay, pectin, barrier, coating, chitosan, film
Abstract

In recent years a lot of effort has been aimed at developing new bio-hybrid nanocomposite barrier packaging materials for foods. Nanocomposite films and coatings with improved properties were produced from nanoclay and polysaccharides such as ultrasonic dispersed chitosan and high pressure fluidized pectin. The intercalation of chitosan in the silicate layers was confirmed by the decrease of diffraction angles while the chitosan/nanoclay ratio increased. Nanocomposite films and multilayer coatings had improved barrier properties against oxygen, water vapor, grease and UV-light transmission. Oxygen transmission was significantly reduced under all humidity conditions. In dry conditions, over 99% reduction and at 80% relative humidity almost 75% reduction in oxygen transmission rates was obtained. All chitosan coating raw materials were "generally recognized as safe" (GRAS) and the calculated total migration was in all cases

Published
2011

11. Ruthenium transport experiments in air ingress accident conditions

Author

Kärkelä, T., Backman, U., Auvinen, A., Zilliacus, R., Lipponen, M., Kekki, T., Tapper, U., and Jorma Jokiniemi

Abstract

In this study the release, transport and speciation of ruthenium in conditions simulating an air ingress accident was studied. Ruthenium dioxide was exposed to oxidising environment at high temperature (1100 -1700 K) in a tubular flow furnace. At these conditions volatile ruthenium species were formed. A large fraction of the released ruthenium was deposited in the tube as RuO2. Depending on the experimental conditions ~1 – 26 wt-% of the released ruthenium was trapped in the outlet filter as RuO2 particles. In stainless steel tube ~0 - 8.8 wt-% of the released ruthenium reached the trapping bottle as gaseous RuO4. A few experiments were carried out, in which revaporisation of ruthenium deposited on the tube walls was studied. In these experiments oxidation of RuO2 took place at a lower temperature. During revaporisation experiments 35 - 65% of ruthenium transported as gaseous RuO4. In order to close mass balance and achieve better time resolution four experiments were carried out using a radioactive tracer.

Published
2007

19. Water-Based Carbon-Coated Copper Nanoparticle Fluid—Formation of Conductive Layers at Low Temperature by Spin Coating and Inkjet Deposition

Author

Eiroma, K., primary, Forsman, J., additional, Hult, E.-L., additional, Auvinen, A., additional, Sipiläinen-Malm, T., additional, Alastalo, A., additional, Tapper, U., additional, Leppäniemi, J., additional, Mattila, P., additional, Lyyränen, J., additional, Sarlin, J., additional, Jokiniemi, J., additional, and Mössmer, S., additional

Published
2012
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24. Colloid cysts of the third ventricle: correlation of MR and CT findings with histology and chemical analysis

Author

Maeder, P P, Holtås, S L, Basibüyük, L N, Salford, L G, Tapper, U A, and Brun, A

Subjects
Adult, Male, Brain Diseases, Cysts, Middle Aged, Magnetic Resonance Imaging, Cerebral Ventricles, Trace Elements, Cholesterol, Journal Article, Humans, Female, Cerebral Ventriculography, Tomography, X-Ray Computed, Aged
Abstract

Eight patients with colloid cysts of the third ventricle were examined with CT and MR. In six, surgical resection was performed and the material was subjected to histologic evaluation; the concentrations of trace elements were determined by particle-induced X-ray emission. Stereotaxic aspiration was performed in two. The investigation showed that colloid cysts are often iso- or hypodense relative to brain on CT (5/8), but sometimes have a center of increased density. Increased density did not correlate with increased concentration of calcium or other metals but did not correlate with high cholesterol content. Colloid cysts appear more heterogeneous on MR (6/8) than on CT (3/8), despite a homogeneous appearance at histology. High signal on short TR/TE sequences is correlated with a high cholesterol content. A marked shortening of the T2 relaxation time is often noticed in the central part of the cyst. Analysis of trace elements showed that this phenomenon is not related to the presence of metals with paramagnetic effects. Our analysis of the contents of colloid cysts does not support the theory that differing metallic concentrations are responsible for differences in MR signal intensity or CT density. We did find that increased CT density and high MR signal correlated with high cholesterol content.

Published
1990

44. Development of a highly controlled gasphase nanoparticle generator for inhalation exposure studies.

Author

Miettinen, M., Riikonen, J., Tapper, U., Backman, U., Joutsensaari, J., Auvinen, A., Lehto, V. P., and Jokiniemi, J.

Subjects
NANOPARTICLES, NANOCRYSTALS, AEROSOLS, AERODYNAMICS, GAS dynamics
Abstract

We have developed a gas-phase nanoparticle generator that produces stable and well-defined size distributions for TiO2. The online analyses of the gas-phase compounds and total number concentration of the generated particles as well as the off-line analysis of the filter samples confirmed the stability of the production. The major advantage of this reactor is that the test substance is directly in the aerosol phase, and thus no preprocessing is needed. This eliminates the physicochemical changes between bulk and administrated material during storing or processing. This system is easy to adjust to different experimental setups and precursors. As a result, wellcharacterized nanomaterials for inhalation exposure studies can be produced. At mass concentration of 30 mg/Nm³, the count mean diameter was 126 nm (geometric SD 1.6), mass mean diameter was 161 nm (2.0), mass median aerodynamic diameter was 125 nm, and the concentrations of harmful gas-phase by-products remained low. The produced powder consisted of crystals of anatase (77 vol%) and brookite (23 vol%), and its specific surface area was 69 m²/g. [ABSTRACT FROM AUTHOR]

Published
2009
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49. Implementing a strategy-driven performance measurement system for an applied research group.

Author

Loch, Christopher H. and Tapper, U. A. Staffan

Subjects
PERFORMANCE, PERFORMANCE evaluation, MILITARY strategy, RESEARCH, MANAGEMENT, ASSOCIATIONS, institutions, etc.
Abstract

Although most companies recognize the importance of R&D for future competitiveness, they often struggle to assess its contribution to the organization. Performance measurement in R&D is particularly difficult because (1) effort levels may not be observable, (2) project success is uncertain, influenced by uncontrollable factors, and (3) success can be assessed only after long delays, or it accrues to other units of the organization. Based on existing literature on the problem, we developed a performance measurement system for the process technology research group of an industrial company. This measurement system systematically supported the business strategy. Moreover, the measures were adjusted for different project profiles: short- versus long term, hardware versus software, routine support services versus breakthrough ideas and knowledge development. The contribution of this article is a description of the process of developing and implementing a comprehensive performance measurement system in a company, based on previous performance management research, and supporting the company's strategy. It is noteworthy that the system was implemented in a research group, where the measurement problems are the most severe. [ABSTRACT FROM AUTHOR]

Published
2002
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