Flockungsmittel zur Entfernung von Mikroplastik aus industriellen Abwässern

Microplastic particles can enter natural bodies of water via wastewater streams. These environmentally hazardous plastic particles are found in more and more bodies of water as well as in food and aquatic life. As part of the research project EmiStop, flocculants for the removal of microplastics from industrial wastewater have been developed. The flocculation of polyethylene, polyvinyl chloride, and polyamide was investigated for nine different combinations of inorganic and organic coagulants and flocculants both in pure water and in industrial wastewater matrices.     

Investigation of the Neuroprotective Impact of Nimodipine on Neuro2a Cells by Means of a Surgery-Like Stress Model

Nimodipine is well characterized for the management of SAH (subarachnoid hemorrhage) and has been shown to promote a better outcome and less DIND (delayed ischemic neurological deficits). In rat experiments, enhanced axonal sprouting and higher survival of motoneurons was demonstrated after cutting or crushing the facial nerve by nimodipine. These results were confirmed in clinical trials following vestibular Schwannoma surgery. The mechanism of the protective competence of nimodipine is unknown. Therefore, in this study, we established an in vitro model to examine the survival of Neuro2a cells after different stress stimuli occurring during surgery with or without nimodipine. Nimodipine significantly decreased ethanol-induced cell death of cells up to approximately 9% in all tested concentrations. Heat-induced cell death was diminished by approximately 2.5% by nimodipine. Cell death induced by mechanical treatment was reduced up to 15% by nimodipine. Our findings indicate that nimodipine rescues Neuro2a cells faintly, but significantly, from ethanol-, heat- and mechanically-induced cell death to different extents in a dosage-dependent manner. This model seems suitable for further investigation of the molecular mechanisms involved in the neuroprotective signal pathways influenced by nimodipine.     

Low-Temperature Aging of Zirconia Ferrules for Optical Connectors

Zirconia ferrules for optical connectors were examined after aging at 85°C and 95% relative humidity. Two degradation mechanisms were the roughening and the deformation of the zirconia ferrule surface. Raman microscopy revealed that this relatively low-temperature degradation of zirconia ferrules is caused by the tetragonal to monoclinic transformation of zirconia, and is accelerated by stress relief during polishing. The surface upheavals associated with low-temperature aging may significantly degrade the performance of optical connectors over time.     

Study of several impinging jets

IntroductionIn the aeronautics field, engine manufacturers arecontinually confronted with the cooling problemsassociated with walls being in contact with overheatinggases. In such situations, the film-cooling technique iscommonly used to protect the first stage of a gas tllrbinerotor or stator from the ever-increasing temperatUre ofthe combustion products. In some critical cases, a moreeffective cooling can be achieved by the presence of anarray of cold air jets impinging on the other side of …     

Restricted second order information for the solution of optimal control problems using control vector parameterization

A new scheme using a Truncated Newton algorithm with and exact Hessian-search direction vector product is presented for the solution of optimal control problems. The derivation of formulae for second order parametric sensitivity analysis of differential-algebraic equations is presented, following earlier published work [V.S. Vassiliadis, E. Balsa-Canto, J.R. Banga, Second order sensitivities of general dynamic systems with application to optimal control problems. Chem. Eng. Sci. 54 (17) (1999) 3851–3860]. An original result in this work is the derivation of Hessian matrix-vector product forms which are shown to have the same computational complexity as the evaluation of first order sensitivities. This result for optimal control Hessian-vector products using control vector parameterization is shown to be a very effective way to solve optimal control problems. It is also noted that this work introduces the use of suitable Truncated Newton solvers which can exploit the exact vector products in using conjugate gradient iterations to converge the Newton equations. Such a solver is the TN algorithm of Nash [(S.G. Nash-Newton type minimization via the Lanczos method. SIAM J. Num. Anal. 21, (1984) 770–778)]. Because no full Hessian update is necessary it is demonstrated that the resulting optimal control solver performs very well for a very large number of degrees of freedom, limited only by the necessity for many right-hand-side calculations in the first and second order sensitivity equations (the Hessian vector product). It is also demonstrated by several case studies that the scheme is capable of starting far from the solution and yet arrive there in almost invariant performance.     

Die Fokker‐Planck‐Gleichung zur Beschreibung von axialen Transport‐ und Mischvorgängen in Rohrreaktoren

One way to explain the mechanism of powder mixing is the Fokker‐Planck equation. The equation comprises two decisive parameters, the transport coefficient U that depends on the active transport of the mixing device and the dispersion coefficient D which describes the mobility of the single particles. The idea is to calculate the dispersion and transport coefficient by using the powder characteristics. To verify this assumption, measurements with different components and different rotation speeds were made.