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  • 1
    Electronic Resource
    Electronic Resource
    The European Union EIAS, EMAS and audits (1998)
    Bingley : Emerald
    Environmental management and health 9 (1998), S. 106-123 
    Details
    ISSN: 0956-6163
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Medicine , Economics
    Notes: Although EU directives were issued quite some time ago, implementation progresses slowly and at an unequal pace in Union member states. Certification of assessors, auditors and verifiers differs widely and is sometimes inordinately complicated; in some instances accountants have stepped into the "vacuum", in others "certification" documents are issued by private organizations. Uniformity is far from being the rule. This paper takes Belgium as a case study. In opposition to what has developed in the USA where federal authority can be completed, even toughened by US regulations, but remained national (viz. federal), in our example responsibility has nearly entirely been devolved to the next (regional) level of authority. A survey was conducted of EMAS implementation in 11 European States: its results are disclosed and commented on.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/09566169810222184
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  • 2
    Electronic Resource
    Electronic Resource
    The range of mobility of the non-cellulosic polysaccharides is similar in primary cell walls with different polysaccharide compositions (1998)
    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 103 (1998), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The molecular mobility of the non-cellulosic polysaccharides in hydrated primary cell walls of three monocotyledons (Italian ryegrass, pineapple and onion) and one dicotyledon (cabbage) was studied using solid-state 13C NMR spectroscopy. These cell walls were chosen as they have different non-cellulosic polysaccharide compositions. By exploiting proton rotating-frame and spin-spin relaxation time constants three different cell wall domains which responded to cross-polarization experiments were identified. Most of the non-cellulosic polysaccharides occupied a mobile domain (C), but some occupied a partly rigid domain (B). Crystalline cellulose occupied a highly rigid domain (A). In the cell walls of Italian ryegrass and pineapple, domain C contained mainly glucuronoarabinoxylans and small amounts of rhamnogalacturonans; domain B contained small amounts of xyloglucans and galacturonans. However, in the cell walls of onion and cabbage, domain C contained mainly rhamnogalacturonans with galactans (in onion) or arabinans (in cabbage) as side chains; domain B contained galacturonans and xyloglucans. Single-pulse excitation was used on Italian ryegrass and cabbage cell walls to reveal signals from a highly mobile fourth domain (D). In Italian ryegrass cell walls domain D contained glucuronoarabinoxylans and small amounts of rhamnogalacturonan, whereas in cabbage cell walls it contained arabinan side chains of rhamnogalacturonans. A novel feature of the research was the use of solid-state 13C NMR spectroscopy to examine the molecular mobilities of the polysaccharides in monocotyledon cell walls that contain glucuronoarabinoxylans.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1399-3054.1998.1030211.x
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  • 3
    Electronic Resource
    Electronic Resource
    Light-Scattering Properties of Representative, Morphological Rutile Titania Particles Studied Using a Finite-Element Method (1998)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 81 (1998), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The light-scattering performance of TiO2 pigment depends intimately upon particle size, size distribution, shape and dispersion quality. TiO2 particles exhibit complex shapes and have anisotropic optical constants, and particulate dispersions of TiO2 are characterized by complicated microstructures such as aggregates and agglomerates. Despite this complexity, the theoretical understanding of light scattering by white pigment has been based upon Mie theory, which is restricted to the case of a single, optically isotropic sphere. We utilize a finite-element method which produces rigorous solutions to Maxwell's equations to determine computationally the light-scattering properties of complex particulate microstructures. This represents a significant step beyond the restrictions of Mie theory, providing a method to determine quantitatively the effects of particle shape, optical anisotropy, and interactions between neighboring particles upon the light-scattering properties of white pigments in coatings. In the present study, we use the finite-element method first to compute the light-scattering properties of a single, morphological rutile particle with a representative size and shape. These results are compared to the light-scattering properties of the optically isotropic, equivalent volume sphere using Mie theory. Neither the average index nor the weighted sum approximation offers clear advantages in this case. Second, the far-field light-scattering properties of two such particles interacting at near field are determined as a function of the interparticle separation. The agglomerated pair of particles exhibits a 20% decrease relative to the single particle in the scattering parameter associated with the hiding power of a paint film. The basis for this decrease is the same as for the crowding effect observed in extensive paint films. The results of both sets of computations are compared to Mie theory to determine the sizes of spherical particles with equivalent scattering cross sections. These comparisons highlight the inherent difficulties in using Mie theory to evaluate particle size by light-scattering methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1998.tb02364.x
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  • 4
    Electronic Resource
    Electronic Resource
    Optical Properties of Aluminum Oxide: Determined from Vacuum Ultraviolet and Electron Energy-Loss Spectroscopies (1998)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 81 (1998), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The optical properties of alpha-Al2O3 have been determined by two independent methods, vacuum ultraviolet (VUV) spectroscopy and electron energy-loss spectroscopy (EELS) over the energy range from 6 to 142 eV. For each experimental method two sets of high-quality data have been measured and analyzed from alpha-Al2O3. The evolution of the differences between the data for each experimental method and its associated analytical method indicate the reliability of the results, and the comparison between the methods emphasizes the relative advantages of each. VUV spectroscopy offers a higher energy resolution, resolving sharper features in the spectra, whereas EELS significantly extends the energy range, which has been exploited here to 140 eV but can be extended even further. Good overall consistency is found, but there are pronounced differences in the valence region from 10 to 30 eV, where strong absorptions are present, increasing the relative variability of the analysis. This demonstrates that accuracy estimates of the optical properties are meaningful only when supplied as a function of energy, because both strong intrinsic absorptions and weak experimental signals make accurate determinations difficult. Moreover, variations in the optical properties are observed most easily in the interband transition strength, Jcv, and are less evident when the optical properties are represented as the complex index of refraction. Because the optical properties can change with specimen origin and preparation and because of the details of data acquisition and numerical analysis procedures, assessing the contributions of each of these methods to our accurate knowledge of the optical constants is essential.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1998.tb02660.x
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  • 5
    Electronic Resource
    Electronic Resource
    Large-Eddy Simulation of Windbreak Flow (1998)
    Springer
    Boundary layer meteorology 87 (1998), S. 275-307 
    Details
    ISSN: 1573-1472
    Keywords: Canopy ; Large-eddy simulation ; Windbreak ; Wind tunnel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract A large-eddy simulation has been performed of turbulent flow around multiple windbreaks set within a wheat canopy under neutral stability conditions. The simulation is validated against a wind tunnel data set taken under similar conditions. Velocity profiles and second-order statistics are presented and compared to those found in the wind tunnel. From the numerical simulation, we discuss spatial distributions of instantaneous velocity fields and pressure statistics, which are important and telling features of the flow that are difficult to measure experimentally. We present a discussion of the momentum balance at various locations with respect to the windbreak, and similarly, we introduce the budget of a passive scalar. These discussions show the importance of the terms in each budget equation as they vary upstream and downstream of the windbreak.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1000945626163
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  • 6
    Electronic Resource
    Electronic Resource
    Turbulent Statistics of Neutrally Stratified Flow Within and Above a Sparse Forest from Large-Eddy Simulation and Field Observations (1998)
    Springer
    Boundary layer meteorology 88 (1998), S. 363-397 
    Details
    ISSN: 1573-1472
    Keywords: Coherent structure ; Field observation ; Forest ; Large-eddy simulation (LES) ; Neutrally stratified shear-driven flow ; Turbulent statistics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Turbulent statistics of neutrally stratified shear-driven flow within and above a sparse forest canopy are presented from a large-eddy simulation (LES) and compared with those from observations within and above a deciduous forest with similar height and foliage density. First- and second-order moments from the LES agree with observations quite well. Third-order moments from the LES have the same sign and similar vertical patterns as those from the observations, but the LES yields smaller magnitudes of such higher-order moments. Turbulent spectra and cospectra from the LES agree well with observations above the forest. However, at the highest frequencies, the LES spectra have steeper slopes than observations. Quadrant and conditional analyses of the LES resolved-scale flow fields also agree with observations. For example, both LES and observation find that sweeps are more important than ejections for the transport of momentum within the forest, while inward and outward interaction contributions are both small, except near the forest floor. The intermittency of the transport of momentum and scalar increases with depth into the forest. Finally, ramp structures in the time series of a passive scalar at multiple levels within and above the forest show similar features to those measured from field towers. Two-dimensional (height-time cross-section) contours of the passive scalar and wind vectors show sweeps and ejections, and the characteristics of the static pressure perturbation near the ground resemble those deduced from field tower-based measurements. In spite of the limited grid resolution (2 m × 2 m × 2 m) and domain size (192 m × 192 m × 60 m) used in this LES, we demonstrate that the LES is capable of resolving the most important characteristics of the turbulent flow within and above a forest canopy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1001108411184
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  • 7
    Electronic Resource
    Electronic Resource
    History and Physics (1998)
    Springer
    Science & education 7 (1998), S. 13-30 
    Details
    ISSN: 1573-1901
    Source: Springer Online Journal Archives 1860-2000
    Topics: Natural Sciences in General
    Notes: Abstract This paper argues that research and teaching in physics and in the history of physics are complementary in nature, and it explores some of the implications of this point of view.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008688309198
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  • 8
    Electronic Resource
    Electronic Resource
    Mouse Chromosome 16 (1998)
    Springer
    Mammalian genome 8 (1998), S. S307 
    Details
    ISSN: 1432-1777
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003359900661
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