Growth processes in a cascade of bioreactors: Mathematical models

Mathematical modeling of continuous multiple bioreactors is complicated by two factors. First, the chemical environments differ in different reactors, so biomass receives an environmental shock when it is transferred between reactors. Second, biomass occurs as discrete cells, which of course are and remain segregated from one another, so an element of biomass that enters a reactor does not mix with the biomass already present. This differs from the behavior of an element of liquid which enters a reactor in that such an element quickly mixes with the liquid already present. The biomass in a bioreactor receiving biomass from an external source is therefore heterogeneous with respect to the history of environmental conditions and composition. This article shows how to construct a mathematical model of multiple bioreactor apparatus that accounts for these complications. It also describes simpler models that do not account for both of them.     

Atomic force microscopy study on structure and properties of irradiation grafted silica particles in polypropylene‐based nanocomposites

Nanosilica particles treated by irradiation grafting polymerization can effectively improve the strength and toughness of a thermoplastic polymer at a rather low filler content. A detailed investigation on the modified nanoparticles in the absence and presence of a polypropylene matrix is carried out by using atomic force microscopy. The results indicate that the loosen agglomerates of the untreated SiO₂ became more compact due to the linkage between the nanoparticles offered by the grafting polymer. In addition, the molecules of the polypropylene matrix are able to diffuse into the modified nanoparticle agglomerates during the melt processing. Entanglement between the molecules of the grafting polymer and the matrix is thus available, which in turn facilitates a strong particle–matrix interfacial interaction. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2218–2227, 2001     

Erinnerung an Max Carstanjen (1856–1934) – Brückenbauer,Werksleiter, Begründer des Großwehrbaues in Gustavsburg

In remembrance of Max Carstanjen (1856–1934) – bridge builder, factory manager, founder of the large weir construction in Gustavsburg. In the year of 1860 the Nuremberg engine Comp. Klett & Co. arranged for the building of a railway bridge over the Rhine above Mainz a building site on the “Mainspitze”, made of which in the following years the bridge construction workshop Gustavsburg developed. After Heinrich Gerber (1832–1912) and Anton Rieppel (1852–1926) Max Carstanjen was from 1901 to 1923 director of this important company, which later belonged to the MAN. In planning and building preparation of bridges and steel structures he carried protruding out there at home and abroad (e.g. Suspension railway in Wuppertal, road bridge in Worms, festival hall in Frankfurt/M.). His special interest applied however for the theoretical and practical treatment of questions of the water movement and the pilot adjustment of rivers, for which he developed the roller drum gate, as well as different designs of ship lifts.     

Beton‐Beton Verbindungssystem in einer Festen Hochgeschwindigkeits‐Fahrbahn

Concrete Connection System for a High Speed Rail Track The concrete‐concrete connections for HSRT's have to perform not only the requirements in terms of the “fatigue load capacity” but also of the maximum deformation. In normal case the proof of deformation is controlling the design. Because of the complex task a structural analysis cannot be performed at the moment. Therefore a design based on experimental methods is necessary. During the development of a practical application the deformations increased super proportional with an increasing load range and is connected to a multiplicity of parameters. The load history is a parameter with a special importance. This report describes how the task can be solved constructive and how to proceed to get reliable results.     

Projekt Steel Earthquake Design (SEQD) – Erdbebenresistentes Stahlbausystem für Wohnhäuser

The SEQD – Steel Earthquake Design – project for earthquake‐resistant residential buildings. The construction material steel is currently mostly applied in highly‐engineered structures like bridges, industrial halls or high‐rise buildings. The SEQD – Steel Earthquake Design – project had the aim of developing a safe and economic solution for small residential buildings in earthquake regions. The basic idea of the system is to combine an engineered steel frame as primary structure with non load‐bearing infill walls from local materials. The new design includes innovative connections between frame elements and special uniaxial couplings between walls and steel frame. Reinforcement of the infill walls is achieved by applying grids from synthetic materials. In October 2004 experimental tests on a prototype structure were carried out in an assembly hall of the Rudolstädter Stahlbau GmbH.     

Code Parallelization for Multi-Core Software Defined Radio Platforms with OpenMP

Since the number of processing cores in a General Purpose Processor (GPP) increases steadily, parallelization of algorithms is a well known topic in computer science. Algorithms have to be adapted to this new processor architecture to fully exploit the available processing power. This development equally affects the Software Defined Radio (SDR) technology because the GPP has become an important processor for SDR platforms. To make use of the entire processing power of a multi-core GPP and hence to avoid system inefficiency, this work provides an approach to parallelize C/C+ + code using OpenMP. This application programming interface provides a rapid way to parallelize code using compiler directives inserted at appropriate positions in the code. The processing load can be shared between all available cores. We use Matlab Simulink as a framework for a model-based design and evaluate the processing gain of embedded handwritten C-code blocks with OpenMP support.We will show that with OpenMP the core utilization is increased. Compared to a single-core GPP, we will present the increase of the processing speed depending on the number of cores. We will also highlight the limitations of code parallelization. In our results, we will show that a straightforward implementation of algorithms without multi-core consideration will cause an underutilized system.     

Designing of Copper Nanoparticle Size Formed via Aerosol Pyrolysis

In this article, the synthesis and structural design of spherical, nonagglomerated particles of copper powder, synthesized by ultrasonic atomization of copper sulfate solutions in hydrogen atmosphere at 1173?K (900?°C), was investigated. Well-controlled particle sizes of Cu powders were obtained from precursor solutions of various concentrations. The mean particle diameters and the ranges of particle size distribution were investigated by scanning electron microscopy (SEM). The diameter values of Cu particles obtained experimentally and estimated theoretically, using the most frequently applied atomization models, were compared. Special attention was paid to our break up capillary waves model, described elsewhere and significantly advanced by Jokanovi???s theoretical approach, which was applied for the first time to a copper metal system as described in this article. The best agreement between the calculated and the experimentally obtained values was found using this model.