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Search Results: 1 - 10 of 18694 matches for " U. Erb "
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Influence of Weather Conditions on the Surface Morphology and Wetting Behaviour of Superhydrophobic Quaking Aspen Leaves  [PDF]
J. J. Victor, U. Erb
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.45A010

The effects of different environmental conditions on the wetting properties and surface morphology of surperhydrophobic quaking aspen leaves harvested during the 2011 growth season are examined. During this particular season quaking aspen leaves were not able to retain their superhydrophobic properties and associated surface structure features as they have usually been able to do in other years. Representative scanning electron microscopy images and wetting property measurements of quaking aspen leaf surfaces harvested throughout this season are presented and discussed with the objective of linking weather induced environmental stresses that occurred in 2011 to the sudden and unusual reduction in non-wetting properties and drastic changes in leaf surface structure. Erosion and regeneration rates of leaf wax crystals and the impact that environmental factors can have on these are considered and used to explain the occurrence of these unexpected changes.

An orthogonal polynomial analogue of the Landau-Pollak-Slepian time-frequency analysis
Wolfgang Erb
Mathematics , 2011,
Abstract: The aim of this article is to present a time-frequency theory for orthogonal polynomials on the interval [-1,1] that runs parallel to the time-frequency analysis of bandlimited functions developed by Landau, Pollak and Slepian. For this purpose, the spectral decomposition of a particular compact time-frequency-operator is studied. This decomposition and its eigenvalues are closely related to the theory of orthogonal polynomials. Results from both theories, the theory of orthogonal polynomials and the Landau-Pollak-Slepian theory, can be used to prove localization and approximation properties of the corresponding eigenfunctions. Finally, an uncertainty principle is proven that reflects the limitation of coupled time and frequency locatability.
Bivariate Lagrange interpolation at the node points of Lissajous curves - the degenerate case
Wolfgang Erb
Mathematics , 2015,
Abstract: In this article, we study bivariate polynomial interpolation on the node points of degenerate Lissajous figures. These node points form Chebyshev lattices of rank $1$ and are generalizations of the well-known Padua points. We show that these node points allow unique interpolation in appropriately defined spaces of polynomials and give explicit formulas for the Lagrange basis polynomials. Further, we prove mean and uniform convergence of the interpolating schemes. For the uniform convergence the growth of the Lebesgue constant has to be taken into consideration. It turns out that this growth is of logarithmic nature.
Accelerated Landweber methods based on co-dilated orthogonal polynomials
Wolfgang Erb
Mathematics , 2012,
Abstract: In this article, we introduce and study accelerated Landweber methods for linear ill-posed problems obtained by an alteration of the coefficients in the three-term recurrence relation of the \nu-methods. The residual polynomials of the semi-iterative methods under consideration are linked to a family of co-dilated ultraspherical polynomials. This connection makes it possible to increase the decay of the residual polynomials at the origin by means of a dilation parameter. This increased decay has advantages when solving linear ill-posed equations in which the spectrum of the involved operators is clustered at the origin. The convergence order of the new semi-iterative methods turns out to be the same as the convergence order of the original \nu-methods. The new algorithms are tested numerically and a simple adaptive scheme is developed in which an optimal dilation parameter is computed.
Optimally space localized polynomials with applications in signal processing
Wolfgang Erb
Mathematics , 2010,
Abstract: For the filtering of peaks in periodic signals, we specify polynomial filters that are optimally localized in space. The space localization of functions having an expansion in terms of orthogonal polynomials is thereby measured by a generalized mean value. Solving an optimization problem including this mean value, we determine those polynomials out of a polynomial space that are optimally localized. We give explicit formulas for these optimally space localized polynomials and determine in the case of the Jacobi polynomials the relation of the generalized mean value to the position variance of a well-known uncertainty principle. Further, we will consider the Hermite polynomials as an example on how to get optimally space localized polynomials in a non-compact setting. Finally, we investigate how the obtained optimal polynomials can be applied as filters in signal processing.
Dropwise condensation on gold
Robert A. Erb
Gold Bulletin , 1973, DOI: 10.1007/BF03215172
Abstract: A new and potentially large-scale use of gold is in coalings to cause steam to condense in the form of drops instead of in the usual form of continuous films. The consequent increase in heat transfer that could be achieved could lead to reductions in both the size and the cost of equipment for desalination and for power generation.
Lucr?ri ?tiin?ifice : Management Agricol , 2009,
Abstract: In the present economic conditions, the correct and fast interpretation of information in a company often makes the difference between success and failure, due to the market competition. Thus, Business Intelligence(BI) tools have spread over the Romanian business environment. On the increasingly competitive market of the travel agencies, the mere travel offers are not enough to ensure the success. Productivity, increased efficiency, quick response and the services offered are important elements in attracting customers
Lucr?ri ?tiin?ifice : Management Agricol , 2009,
Abstract: The purpose of this paper is to present the theoretical and practical foundations at the basis of the development of a virtual business, and in particular an application for online orders that facilitates the process of ordering products to suppliers that provide home delivery. In this paper, starting from the presentation of the basic theoretical elements in the domain of economic and information technology, I elaborated a new economic and information model for virtual business, adjustable to the Romanian business environment and not only. Projecting an electronic business is a natural consequence, set both by the economic environment and by the technological one.
A Cause and Effect Analysis of University – Business Cooperation for Regional Innovation in Romania
Cristina ?ERB?NIC?
Theoretical and Applied Economics , 2011,
Abstract: This paper underlines the main roles of universities in regional innovation systems, as well as the barriers to university – business cooperation for regional innovation. At the same time, the study proposes a qualitative content analysis of Regional Innovation Strategies (RIS) that were drafted for six of the eight Romanian NUT 2 regions, in order to identify the causes of the weak university – business cooperation. Results are then shyntethised in a cause and effect map that can be a useful diagnosis and control tool in regional planning.
Knowledge Circulation between Universities, Public Research Organizations and Business in the EU 27. Drivers, Barriers, Actions to be put Forward
Cristina ?ERB?NIC?
European Journal of Interdisciplinary Studies , 2011,
Abstract: The purpose of this study is to explore different patterns of knowledge circulation between universities, public research organizations (PROs) and businesses in the EU27. To this end, a Knowledge circulation index was created based on funding flows (business funded R&D in higher education and government sectors), co-operation-based innovation indicators, bibliometric data and patent statistics. The results have confirmed a leading position for Finland, Netherlands, Denmark, Belgium, the UK and Slovenia, countries with a long tradition in knowledge transfer, but with a sustainable base for networks and links between all innovation actors. The paper advances some future paths to action, such as rising up SMEs’ profile in knowledge circulation, finding the best coordination matrix for already existent support network or finding solutions to reduce the strong dependence on public and EU funding.
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