Fractional derivatives and recurrent neural networks in rheological modelling – part I: theory

The aim of this paper was to develop a general approach based on fractional time derivatives and recurrent neural networks to model the rheological behaviour of asphalt materials. The paper focuses on elastic and viscoelastic material characteristics. It consists of two parts. In this first part, the theoretical aspects of modelling are discussed. A brief introduction into the theory of rheological elements based on fractional time derivatives is provided. The fractional differential equation of a general rheological element (base element) is developed from which a huge variety of other rheological elements can be derived, e.g. fractional Newton, Kelvin and standard solid elements. A new approach is presented for solving the fractional differential equations. Artificial neural networks are developed to compute the stress–strain–time behaviour of fractional rheological elements in a numerical efficient way. The approach is tested and verified. The second part of this work will appear later. It will be focused on applications of the new theoretical work to pavement engineering problems.     

Comments on solid state hydrogen storage systems design for fuel cell vehicles

In recent years, significant research and development efforts were spent on hydrogen storage technologies with the goal of realizing a breakthrough for fuel cell vehicle applications. This article scrutinizes design targets and material screening criteria for solid state hydrogen storage. Adopting an automotive engineering point of view, four important, but often neglected, issues are discussed: 1) volumetric storage capacity, 2) heat transfer for desorption, 3) recharging at low temperatures and 4) cold start of the vehicle. The article shall help to understand the requirements and support the research community when screening new materials.     

Public acceptance for environmental taxes: Self-interest,environmental and distributional concerns

While strongly recommended by economists, it has often been politically difficult to impose taxes on externalities. There is a substantial literature on public attitudes towards environmental taxes. There has, however, been few comprehensive attempts to understand attitudes towards environmental taxes.     

Parameter-study on the influence of steel fibers and coarse aggregate content on the fresh properties of self-compacting concrete

Self-compacting concrete (SCC) offers several economic and technical benefits; the use of steel fibers extends its possibilities. Steel fibers bridge cracks, retard their propagation, and improve several characteristics and properties of the concrete. Fibers are known to significantly affect the workability of concrete. Therefore, an investigation was performed to compare the properties of plain SCC and SCC reinforced with steel fibers. Two mixtures of SCC with different aggregate contents were used as reference. Each of the concretes was tested with four types of steel fibers at different contents in order to answer the question to what extent the workability of SCC is influenced. The slump flow, a fiber funnel and the J-ring test were used to evaluate the material characteristics of the fresh concrete. This paper discusses the suitability of the applied test methods and the effect of the coarse aggregate content, the content and type of steel fibers on the workability of SCC.     

A highly sensitive method to determine the washing resistance of artificial hair colours

Citation: IFSCC Magazine, 11 (2008) (2) 139–142 Abstract: Due to the improved performance of modern hair colorants, the high natural variability in hair qualities and the individual influences of manual product applications, colour care effects of cosmetic treatments are very difficult to detect. A new, highly sensitive test method to study the colour fading behaviour of human hair was established for a large variety of cosmetic treatments. This method is based on an automatic multistage application of standard wool tissues combined with automatic colour evaluation by means of CIE L × a × b × measurements (DIN 5033). The delta E values are the main interest because they include all information regarding the L (black vs. white), a (red‐green) and b (blue‐yellow) axes defined in the Hunter Lab colour space. For validation of this new method, different permanent and non‐permanent hair colour shades were applied to undamaged light brown Caucasian hair strands. The hair strands were washed manually stepwise 30 times and the colour loss compared with the results obtained on wool tissues using an automatic application system. For most of the investigated hair colours, a coefficient of determination of r2 > 0.99 was achieved. Modern permanent hair colours show a high resistance to cosmetic treatments. Over 90% of the initial colour result was retained after 30 product applications. Shampoo and conditioner formulations induce different degrees of colour loss in hair. In basic formulas significant influences of single surfactants could be detected. The new method using wool tissues correlates very well with that using manually washed Caucasian hair strands. This automatic method is very time‐effective and offers an excellent reproducibility with a high sensitivity for assessing product influences on artificial hair colours. Keywords: Color fading, color protection, color retention, hair color resistance, hair wash simulation Paper presented at the IFSCC Conference 2007, Amsterdam, The Netherlands     

Continuous Model-Driven Engineering

CMDE has been successfully applied in several industrial projects, including telecommunication services, supply-chain management, bioinformatics, logistics, and healthcare. In all these cases, agility at the customer, user, and application level proved key to aligning and linking business and IT. We now expect an additional boost when integrating this approach into a processor project-management environment that oversees development and evolution. This environment will include deadline management and progress reports, automatically informing all relevant parties when certain actions are required, managing different versions and product lines, and automatically steering the build and quality-management process. Perhaps not surprisingly, the development of this management environment proved to be a prime application of CMDE.     

Factorial interlaboratory tests for microbiological measurement methods

This paper presents a validation approach for microbiological methods based on a combination of interlaboratory tests and factorial experiments. It requires not more than 4 participants but is achieving comparable statistical confidence as in method validation studies with 8–12 participants, if properly designed. The approach is illustrated by a comprehensive validation of the Arxula adeninivorans yeast estrogen screen (A-YES) assay for the detection of estrogenic activity in mineral water.     

Accelerated Visualization of Dynamic Molecular Surfaces

Molecular surfaces play an important role in studying the interactions between molecules. Visualizing the dynamic behavior of molecules is particularly interesting to gain insights into a molecular system. Only recently it has become possible to interactively visualize dynamic molecular surfaces using ray casting techniques. In this paper, we show how to further accelerate the construction and the rendering of the solvent excluded surface (SES) and the molecular skin surface (MSS). We propose several improvements to reduce the update times for displaying these molecular surfaces. First, we adopt a parallel approximate Voronoi diagram algorithm to compute the MSS. This accelerates the MSS computation by more than one order of magnitude on a single core. Second, we demonstrate that the contour‐buildup algorithm is ideally suited for computing the SES due to its inherently parallel structure. For both parallel algorithms, we observe good scalability up to 8 cores and, thus, obtain interactive frame rates for molecular dynamics trajectories of up to twenty thousand atoms for the SES and up to a few thousand atoms for the MSS. Third, we reduce the rendering time for the SES using tight‐fitting bounding quadrangles as rasterization primitives. These primitives also accelerate the rendering of the MSS. With these improvements, the interactive visualization of the MSS of dynamic trajectories of a few thousand atoms becomes for the first time possible. Nevertheless, the SES remains a few times faster than the MSS.     

Zutrittskontrolle mit Gesichtserkennung

Firmen&ProdukteDehn Austria

überspannungs-schutz in der Telekommunikation     

Service Engineering: Linking Business and IT

With its strong emphasis on modularization, service-oriented computing radically alters the way business processes are modeled, realized, and maintained. Domain-specific services virtualize complex functions of the underlying business applications so that they can be loosely coupled to form transorganizational processes. This level of abstraction fosters agility and lessens traditional provider dependence. Service-oriented design has long driven the development of the telecommunications infrastructure and applications, especially intelligent network services. Applying the same principles of domain specificity, visualization, loose coupling, and seamless vertical integration to business processes has the potential to lead to a new generation of personalized, secure, and highly available Web services