Modeling the effect of a superabsorbent polymer material as desiccant in maize drying using CFD

Maize is an important foodstuff in many countries, and one of most susceptible crops to mold and aflatoxin contamination, which results in considerable postharvest losses and is a burden to consumers’ health, especially in developing countries. The timely drying of harvested maize is essential to halt mold development, ensuring safe storage. The effect of the incorporation of a superabsorbent polymer (SAP) as desiccant in a maize dryer was studied using computational fluid dynamics simulations which accounted for heat and mass transfer between maize, SAP and air. The adsorption capacity and adsorption rate of a commercial SAP material were experimentally determined at different temperature and relative humidity levels, which served as basis for the adsorption model required in the simulations. A maize bulk with SAP packages distributed in it was modeled. Results showed that the SAP material increases the drying rate substantially, particularly in the upper bulk zone where the air reaching it is dehumidified the most. The maize closer to the upper bulk surface starts drying from the beginning of the process instead of lagging for hours or days before the drying front reaches it. An inconvenience of the SAP material is the tendency of granules to swell and stick together as moisture reaches a threshold, which may reduce its performance. Thus, provided this issue is resolved or minimized, SAP materials could successfully assist the rapid drying of maize and other crops. They may also be used during storage to avoid rewetting of the crops during periods of high relative humidity.     

Adhesion of a rigid punch to a confined elastic layer revisited

The adhesion of a punch to a linear elastic, confined layer is investigated. Numerical analysis is performed to determine the equivalent elastic modulus in terms of layer confinement. The size of the layer relative to the punch radius and its Poisson’s ratio are found to affect the layer stiffness. The results reveal that the equivalent modulus of a highly confined layer depends on its Poisson’s ratio, whereas, in contrast, an unconfined layer is only sensitive to the extent of the elastic film. The solutions of the equivalent modulus obtained from the simulations are fitted by an analytical function that, subsequently, is utilized to deduce the energy release rate for detachment of the punch via linear elastic fracture mechanics. The energy release rate strongly varies with layer confinement. Regimes for stable and unstable crack growth can be identified that, in turn, are correlated to interfacial stress distributions to distinguish between different detachment mechanisms.     

Die Vorratsdatenspeicherung aus datenschutzrechtlicher Sicht

Mit dem „Gesetz zur Neuregelung der Telekommunikationsüberwachung und anderer verdeckter Ermittlungsma?nahmen sowie zur Umsetzung der Richtlinie 2006/24/EG“ wurde zum 1.1.2008 die Vorratsdatenspeicherung von Telekommunikationsverbindungsdaten eingeführt. Gegen diese gesetzliche Regelung führt der vorliegende Beitrag nicht nur erhebliche verfassungsrechtliche Bedenken, sondern auch Vorbehalte gegen bestehende Regelungsdefizite ins Feld.     

Design of a Microstructured System for the Homogenization of Dairy Products at High Fat Content Part II: Influence of Process Parameters

Partial homogenization using a microstructured SHM (Simultaneous Homogenizing and Mixing) valve significantly reduces aggregation of fat globules within their homogenization by feeding the continuous phase directly into the droplet disruption zone (as discussed in part I of this work). It allows homogenization of cream containing up to at least 42 vol.‐% fat, and thus, significantly reduces processing costs without loss in product quality, i.e., overall process intensification. The present article details current results on the influence of material parameters, i.e., emulsifier system and fat content, and process parameters, i.e., homogenizing pressure and the temperature of both streams, on the fat globule size distribution. In contrast to conventional technology, SHM valve technology generates decreasing droplet sizes with increasing pressure or with increasing temperature of the homogenizing stream. This novel technique breaks new ground in dairy product design.     

Sheet metal forming of piezoceramic-metal-laminar structures—Simulation and experimental analysis

Adaptive systems with piezoelectric components offer significant opportunities for the active control of dynamic behaviour. Vibration and acoustics control as well as structural health monitoring are also possible. However ineffective production technologies prevent industrial applications. The authors are therefore proposing the integration of piezo-modules inside a double-layer sheet. The use of semi-cured adhesive avoids shear-forces being transferred to the piezo-modules during forming. After forming the adhesive will cure and the transfer of piezoelectric strain to the sheet is made possible. A detailed finite-element-model incorporating the electro-mechanical characteristics of the piezo-modules has been developed. The simulation results were validated experimentally.     

Polarisation transformer on Ti:LiNbO3 with reset-free optical operation for heterodyne/homodyne receivers

Experimental results for an integrated-optical state-of-polarisation (SOP) controller device on Ti:LiNbO3 for continuous broadband optical operation, with small temperature sensitivity and the possibility of integration with polarisation- insensitive directional couplers, are presented.