Recycling von marinen Sekundärrohstoffen

As a waste product, oyster shells pose a major environmental pollution problem and the reuse of the material is becoming increasingly important. Since the comminution process in the recycling of secondary raw materials defines the properties of the material, oyster shells were grinded using a planetary ball mill and an impact mill and the fractions obtained were analyzed in terms of size and shape and compared with each other. A comminuted material from the impact mill was used for a series of wetting experiments, which helped to demonstrate the surface free energy of the material.     

Mo–Si–B alloys for ultra-high-temperature space and ground applications: liquid-assisted fabrication under various temperature and time conditions

Journal of Materials Science - Boron-doped molybdenum silicides have been already recognized as attractive candidates for space and ground ultra-high-temperature applications far beyond limits of...     

Neuro-semantic prediction of user decisions to contribute content to online social networks

Neural Computing and Applications - Understanding at microscopic level the generation of contents in an online social network (OSN) is highly desirable for an improved management of the OSN and the...     

Pairwise testing for software product lines: comparison of two approaches

Software Product Lines (SPL) are difficult to validate due to combinatorics induced by variability, which in turn leads to combinatorial explosion of the number of derivable products. Exhaustive testing in such a large products space is hardly feasible. Hence, one possible option is to test SPLs by generating test configurations that cover all possible t feature interactions (t-wise). It dramatically reduces the number of test products while ensuring reasonable SPL coverage. In this paper, we report our experience on applying t-wise techniques for SPL with two independent toolsets developed by the authors. One focuses on generality and splits the generation problem according to strategies. The other emphasizes providing efficient generation. To evaluate the respective merits of the approaches, measures such as the number of generated test configurations and the similarity between them are provided. By applying these measures, we were able to derive useful insights for pairwise and t-wise testing of product lines.     

Cycle time-oriented mid-term production planning for semiconductor wafer fabrication

Wafers are produced in an environment with uncertain demand and failure-prone machines. Production planners have to react to changes of both machine availability and target output, and revise plans appropriately. The scientific community mostly proposes WIP-oriented mid-term production planning to solve this problem. In such approaches, production is planned by defining targets for throughput rates and buffer levels of selected operations. In industrial practice, however, cycle time-oriented planning is often preferred over WIP-oriented planning. We therefore propose a new linear programming formulation, which facilitates cycle time-oriented mid-term production planning in wafer fabrication. This approach plans production by defining release quantities and target cycle times up to selected operations. It allows a seamless integration with the subordinate scheduling level. Here, least slack first scheduling translates target cycle times into lot priorities. We evaluate our new methodology in a comprehensive simulation study. The results suggest that cycle time-oriented mid-term production planning can both increase service level and reduce cycle time compared to WIP-oriented planning. Further, it requires less modelling effort and generates plans, which are easier to comprehend by human planners.     

A New Stable Splitting for the Isentropic Euler Equations

In this work, we propose a new way of splitting the flux function of the isentropic compressible Euler equations at low Mach number into stiff and non-stiff parts. Following the IMEX methodology, the latter ones are treated explicitly, while the first ones are treated implicitly. The splitting is based on the incompressible limit solution, which we call reference solution. An analysis concerning the asymptotic consistency and numerical results demonstrate the advantages of this splitting.