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  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK : Munksgaard International Publishers
    Indoor air 6 (1996), S. 0 
    ISSN: 1600-0668
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Architektur, Bauingenieurwesen, Vermessung , Medizin
    Notizen: Abstract A European project started at the end of 1992, in which, in addition to current methods, trained sensory panels were used to investigate office buildings all over Europe. The main aim of this EC-Audit was to develop assessment procedures and guidance on ventilation and source control, to help optimize energy use in buildings while assuring good indoor air quality.In each of nine countries, six or more office buildings were selected. Measurements were performed at five selected locations in each building. The buildings were studied while normally occupied and ventilated to identify the pollution sources in the spaces and to quantify the total pollution load caused by the occupants and their activities, as well as the ventilation systems. The investigation included physical and chemical measurements, assessment of the perceived air quality in the spaces by a trained sensory panel, and measurement of the outdoor air supply to the spaces. A questionnaire for evaluating retrospective and immediate symptoms and perceptions was given to the occupants of the buildings. The building characteristics were described by use of a check-list. The annual energy consumption of the buildings and the weather conditions were registered.This paper presents results and conclusions of the audit in 56 buildings in Europe. However, the analysis and discussions of the results are a summary of the work done, and are focused mainly on comparison between sensory assessments and the other measurements performed.Furthermore, this paper brings the results of the study based on a two-factor analysis. A paper dealing with results on a multifactorial analysis is in preparation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    ISSN: 1432-0495
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie
    Notizen: Abstract The area studied is part of the “Ried Central” of the Ill river (Middle Alsatian plain in northeastern France). This area is located mainly in the present floodplain of the Ill. The closeness of the water table to the surface results in quasi general soil hydromorphism. The economic constraints of the last two decades led to deep changes in agricultural activities in the study area. These have essentially involved a marked extension of intensive cultivation of grain corn at the expense of grasslands. The study of the influence of this change on the parallel increase in the concentration of nitrate in groundwater is only feasible when a multidisciplinary approach is adopted. The analyses carried out in the field and in the laboratory show that nitrate reduction occurs in gleyed or peaty horizons of hydromorphic soils. The aptitude and efficiency of the permanent ambient vegetation (alluvial forests and grasslands) in retaining nitrate must be emphasized. The amount of nitrate eliminated from the aquifer by rivers fed by this aquifer is considerable. This evacuation of nitrate into the Ill is a fine example of waste and illustrates the absurdity of the economic situation responsible for excessive nitrogen fertilization of farmlands. In determining hazard zones, this study also proposes practical solutions to the problem of nitrate pollution: diminution of land area under cultivation, reintroduction of grasslands, and a more judicious use of nitrogen manure.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Pharmaceutical research 12 (1995), S. 1354-1360 
    ISSN: 1573-904X
    Schlagwort(e): transdermal drug delivery ; prediction of percutaneous absorption ; permeability ; maximum flux ; sunscreens
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Purpose. The goal of this study was to quantify the transdermally absorbed amounts of the sunscreens octyl dimethyl p-aminobenzoic acid, oxybenzone, 4-isopropyl-dibenzoylmethane, 3-(4-methylben-zylidene)-camphor, isoamyl-4-methoxycinnamate, the repellent and plasticizer dibutyl phthalate, the antioxidant 3.5-di-t-butyl-4-hydroxyanisol, and the antimicrobial compounds butyl-4-hydroxybenzoate, biphenyl-2-ol, and 2,4,4′-tri-chlor-2′-hydroxydiphenylether (tri-closane). Permeabilities P B and maximum fluxes J max should be correlated with relevant physicochemical properties. Methods. Saturated solutions of the above-mentioned compounds in a propylene glycol/water mixture were applied to the skin using glass chambers which were fixed to the upper arms of volunteers. Maximum fluxes were calculated from concentration decreases in the vehicle. Results. A linear relationship between the logarithms of permeabilities P B of the penetrants (0.02–0.28 cm h−l) and the corresponding octanol/vehicle partition coefficients PC Oct/v (166–186,208) was found. Consequently, the influence of aqueous boundary layers could be neglected. However, the slope of the resulting straight line of 0.38 is considerably smaller than unity indicating that PC Oct/v does not represent the lipophilicity of the stratum corneum adequately. Maximum fluxes range from 0.5 to 130 µg cm−2 h−1. A general equation for the calculation of J max was derived based on experimental data taking into account the PC Oct/v and the solubilities c sV of the respective penetrants in the vehicle.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Pharmaceutical research 12 (1995), S. 1781-1785 
    ISSN: 1573-904X
    Schlagwort(e): hydrocolloid embeddings ; √t kinetics ; zero-order release ; hydrodynamic stress ; diffusion control ; erosion control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Purpose. The subject of the study was the influence of hydrodynamic stress on the drug release from direct compressed hydrocolloid embeddings. Additionally a correlation between the release kinetics and different polymer characterising parameters was attempted. Methods. The drug release was fitted to an expanded Korsmeyer equation to describe the release kinetics. The influence of the stirring rate of the paddle in the USP paddle apparatus on the Mean Dissolution Time (MDT) was expressed as quotient of the MDT's at the stirring rate of 200 and 100 min−1. Results. If the drug release followed the square root of time kinetics, nearly no effect of the agitation speed on the release rate was observed. To achieve this diffusion controlled drug release the developing gel layer had to be hydrated very well and resistant against erosion (viscosity of at least 4000 mPa · s of the 2% polymer solution and a small expansion of the swelling gel especially at the beginning of the release). The erosion controlled zero order release was generally much affected by the hydrodynamic stress except for some hydrocolloids with incomplete swelling. Thus, it was possible to define a new release mechanism, the polymer particle erosion. The drug release was controlled by the attrition of partially swollen polymer particles and not by the polymer dissolution or drug diffusion. Conclusions. Polymer particle erosion or diffusion control should be the release controlling mechanisms for negligible influence of hydrodynamic stress.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Journal of low temperature physics 117 (1999), S. 823-830 
    ISSN: 1573-7357
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The transport, magnetic and thermodynamic properties of RuSr 2 GdCu 2 O 8 and related compounds are reviewed. These indicate uniform coexistence of superconductivity (T c =46K) and ferromagnetism (T M =132K) in which the former arises in the CuO 2 planes and the latter in the RuO 2 planes. The earliest data indicated a typical underdoped cuprate with local Ru moment ferromagnetism, the absence of pairbreaking and transport properties dominated by the CuO 2 planes. However, recent results suggest a more complex scenario of itinerant ferromagnetism and exchange coupling between the CuO 2 and RuO 2 layers.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    ISSN: 1573-7357
    Schlagwort(e): 74.25.Fy ; 74.25.Ha ; 74.50.+r ; 74.72.Gr
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We show from muon spin relaxation (μSR) studies on mercury HTS superconductors that a 50-fold increase in irreversibility field obtained by partial substitution of Re for Hg is due to metallisation of the Hg/Re layer. Induced superconductivity on this metallic layer doubles the overall superfluid density. This suggests a new approach to the design of high performance HTS materials: metallising one of the non-CuO2 interlayers and thereby greatly enhancing the superconducting properties.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    ISSN: 1572-9605
    Schlagwort(e): Muon spin rotation ; magnetic penetration depth ; Tl2Ba2CuO6+δ ; overdoped ; pair breaking
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Physik
    Notizen: Abstract We report transverse-field muon-spin-rotation experiments carried out on Tl2Ba2CuO6+δ . This system spans the whole overdoped regime, andT c is reduced by excess oxygen doping, which increases the normal-state carrier concentration. In the heavily overdoped regimeσ(0) is found to scale linearly with the superconducting critical temperatureT c , similar to the behavior previously observed for other cuprates in the underdoped regime. However, for the overdoped region one has to explain the reduction ofσ 0, thus the increase of the magnetic penetration depthλ, in spite of an increasing normal-state carrier concentration. We discuss some possible explanations for this behavior.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    ISSN: 1572-9540
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We present an extensive study on the parallel reduction of Tc and the condensate density in ceramic YBCO samples, upon substitution of Cu by Zn. Strong evidence is collected in support of non magnetic pair breaking in a d‐wave pairing state.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Hyperfine interactions 105 (1997), S. 131-137 
    ISSN: 1572-9540
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We have studied the magnetic phase diagram for the bilayer compound Y1-x Cax Ba2 Cu3 O6 in the regime of low doping (hole concentration within a CuO2 plane, psh 〈 0.1). For psh 〈 0.03, the data demonstrate the freezing of the spin degrees of freedom associated with the doped holes into a spin‐glass‐like state which is superimposed on the preexisting long range order of the Cu2+ spins. Only a single spin‐glass like transition at a temperature Tg is observed for samples in the hole concentration range 0.03 〈 psh 〈 0.1. While the threshold for the occurrence of superconductivity is almost the same (psh 〉 0.06) for the Y1-x Cax Ba2 Cu3 O6 and the La2-x Srx CuO4 systems, the magnetic correlations that coexist with superconductivity are considerably stronger in the bilayer Y1-x Cax Ba2 Cu3 O6 system as indicated by significantly increased transition temperatures Tg.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    ISSN: 1572-9540
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Muon‐spin‐rotation studies on a variety of polycrystalline cuprate high‐T_ c superconductors reveal a generic dependence of the superconducting transition temperature T_ c upon condensate density throughout the entire range of hole doping. Upon full oxygenation the CuO chains in YBa2Cu3O7-\delta become metallic and superconducting and the condensate density is dramatically enhanced. The very rapid suppression of the condensate density n_ s upon Zn substitution in YBa2(Cu1-xZnx)3O6+\delta is inconsistent with s‐wave pairing and magnetic scattering but points towards a d‐wave pairing state with non‐magnetic scattering in the unitarity limit.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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